TW201227942A - Light emitting unit array and projection system - Google Patents

Abstract

A light emitting unit array including a plurality of micro-light emitting diodes (μ -LEDs) is provided. The μ -LEDs are arranged in an array on a substrate. Each of the μ -LEDs includes a reflector layer, a light emitting layer, and a light collimation structure. The light emitting structure is disposed on the reflector layer and includes a first type doped semiconductor layer, an active layer, and a second type doped semiconductor layer, while the first type doped semiconductor layer, the active layer, and the second type doped semiconductor layer are sequentially stacked. The first type doped semiconductor layer, the active layer, and at least a portion of the second type doped semiconductor layer are sandwiched between the reflector layer and the light collimation structure.

Description

201227942 VI. Description of the Invention: [Technical Field] The present disclosure relates to an array of light-emitting units and a display device, and more particularly to a micro-light emitting diode array (μ-LED) and using the same A light emitting diode array is used as a projection device for a projection imaging source. [Prior Art] The characteristics of the LEDs with high efficiency, long life, etc. make the current LED light source widely used. Among them, led micro projection system makes revolutionary changes in projection and display products. At present, the micro projection system is divided into two types: Stand alone and Embedded. Intended type refers to the built-in micro-projection system in the original device, such as: mobile phones, digital cameras, handheld game consoles, etc. However, the problem that must be overcome before embedding the projector in a mobile electronic product is the problem of miniaturization. The current micro-projection technology, regardless of digital light processing (DLP) projectors, liquid crystal projector (LCP) and reflective liquid crystal (LCOS) projection display devices A light machine engine must be provided. Therefore, such a product must take into consideration both the projection brightness and the reduced volume, such as the formation of a super-small (<3 ec) projection system, which has its design limitations and difficulties. In view of this, the micro-projection system developed by the μ-LED array display type light source has been born. The μ-LED array display type light source is the projection imaging source, 201227942. Therefore, this type of micro-projection system does not require a optomechanical engine. In general, a μ-LED array display source can be combined with a projection lens to form a high-efficiency, ultra-small projection system with a total potential of less than 3 cc. Overall, this type of projection system can achieve the purpose of embedded micro-projection, which is the door-to-air that all micro-projection technologies cannot currently achieve. Figure 1 illustrates a known projection system using a miniature light emitting diode array display type light source. As can be seen from Fig. 1, the projection system 1 includes a miniature light emitting diode array 110, a microlens array 12A, and a projection lens 130 disposed on the substrate 10. The miniature light-emitting diode array ι10 is an array structure composed of a plurality of micro-light-emitting diodes, and each of the micro-light-emitting diodes can be regarded as a single element for display. The microlens array 120 is disposed on the miniature light emitting diode array 110 and includes a plurality of microlenses. Each microlens can be placed corresponding to a single element (i.e., a miniature light emitting diode). The projection lens 130 is disposed on the optical path of the light emitted by the micro LED array 110. 2 is a ray tracing diagram of a miniature illuminating diode array in the projection system of FIG. 1 and FIG. 3 is a far field ray of a micro illuminating diode array in the projection system of FIG. Intensity distribution. Referring to FIG. 2 and FIG. 3 simultaneously, the arrangement of the microlens array 120 on the micro LED array 110 causes the light emitted by the micro LED array 11 to be roughly divided into three groups A, B, and C. When the miniature light emitting diode array 110 displays an image, the adjacent two miniature light emitting diodes can display different degrees of acceptance and/or color to form a desired display image. However, as can be seen from FIG. 2 and FIG. 3, the portion of the light emitted by each of the micro-light-emitting diodes 201227942 belonging to the group B and the group C is obliquely emitted' while the light emitted by the adjacent miniature light-emitting diodes is mutually Interference, this phenomenon is often referred to as optical cross talk. At this time, the projection system 100 will cause poor image quality due to such an optical crosstalk phenomenon, such as a decrease in image contrast and a decrease in projection brightness. Therefore, how to make the light of the miniature light-emitting diode array 110 more collimated is a problem that must be overcome when the miniature light-emitting diode array display type light source is used in a projection system. SUMMARY OF THE INVENTION The present disclosure provides an array of light emitting cells including a plurality of miniature light emitting diodes. The miniature light emitting diodes are arranged in an array on the substrate, and each of the micro LEDs comprises a reflective layer, a light emitting structure and a light collimating structure. The light emitting structure is disposed on the reflective layer, and the light emitting structure comprises a first type doped semiconductor layer, an active layer and a second type doped semiconductor layer which are sequentially stacked. The first type doped semiconductor layer, the active layer, and at least a portion of the second type doped semiconductor layer are sandwiched between the reflective layer and the light collimating structure. The present disclosure further provides an array of light emitting cells comprising a plurality of miniature light emitting diodes arranged in an array on a substrate. Each of the micro-light emitting diodes includes a reflective layer, a light emitting structure, and a first photonic crystal structure layer. The light emitting structure is disposed on the reflective layer, and the light emitting structure comprises a first type doped semiconductor layer, an active layer, and a second type doped semiconductor layer which are sequentially stacked. The first type of doped semiconductor layer, the line layer, and the second type doped semiconductor layer are sandwiched between the reflective layer and the first photonic crystal structure layer. 201227942 discloses another type of feeding system, including display single staggered column and projection lens. The display unit array includes a plurality of micro-light emitting diodes arranged in an array on a substrate. Each of the miniature light-emitting diodes includes a reflective layer, a light-emitting structure, and a light collimating structure. The light emitting structure is disposed on the reflective layer, and the light emitting structure comprises sequentially stacking the (four)-type doped semiconductor layer, the line layer and the first-type semiconductor layer. The 苐-type doped semiconductor layer, the active layer, and at least a portion of the second-type semiconductor layer between the reflective layer and the glazed straight structure. The projection = lens group is located on the optical path of the display light of the display unit array. The above described features and advantages of the present invention will become more apparent from the following description. [Embodiment] In order to reduce the total volume of the projection system and to have an ideal imaging quality, in the micro-light emitting diode array for displaying the pupil surface, each of the micro-light-emitting diodes must provide a collimated light-emitting effect. That is to say, in the direction of the zero angle of the normal direction of the display surface, the light emitted by the miniature light-emitting diode is ideally emitted along a zero angle or a small light exit angle (for example, a ±3 degree). However, in the known design, as shown in Figs. 2 and 3, even with the microlens array, the light emitted by the micro-light emitting diode has oblique rays of the group B and the group c. Therefore, to achieve the collimated light-emitting effect <the light-emitting unit array formed by the political light-emitting body is still necessary for improvement. The design of several types of light-emitting unit arrays will be exemplified below, so that the miniature light-emitting diodes in the light-emitting unit array have a collimated light-emitting effect and an ideal luminous efficiency. Applying these arrays of illumination units to the projection system helps to achieve the imaging quality of the 201227 42U projection system. Of course, the illumination unit described in the following embodiments is described by taking the image as an example, but the invention is not particularly limited thereto. That is, everything that needs to have

The illuminating element array of the present invention can be applied to a product or design that collimates the light-emitting effect. FIG. 4a to FIG. 4i illustrate a method of fabricating an array of light emitting cells according to a first embodiment of the present disclosure. Referring to FIG. 4a, a thin layer 222a of doped semiconductor material and a plurality of light collimating structures 224 are formed on the substrate 22A. In the present embodiment, the substrate 220 is, for example, a blue stone substrate or other substrate suitable for use in a process for insect crystals. The array of light collimating structures 224 is arranged on the doped semiconducting material layer 222a and the adjacent two light collimating structures 224 are separated by a gap G. Each of the light collimating structures 224 is fabricated, for example, on a thin layer 222a of doped semiconductor material by an optical thin film process. In the present embodiment, the light collimating structure 224 may be a distributed Bragg reflector (DBR). In other words, the light collimation structure 224 is a multilayer film composed of a material layer having different refractive indices, such as a multilayer film of TaA/SiO2, a multilayer film of Nb2〇5/Si〇2, a multilayer film of Ti02/Si〇2, A multilayer film of Al203/Si〇2, a multilayer film of iT〇/si〇2. The reflectivity of the light collimating structure 224 can be determined by the number of laminations of the multilayer film and the thickness of each material layer. In addition, the light collimating structure 224 may also be an omni-directional reflector (ODR), which is, for example, a multilayer film composed of a metal material layer and an oxide material layer, such as a multilayer film of Al/Si〇2, Ag. /Si02 multilayer film, etc. Then, please refer to Figure 4b to Figure 4d, using the lateral stray crystal technology,

S 201227942 The portion of the doped semiconductor material thin layer 222a exposed by the gap G grows the semiconductor material SM, and continuously increases the thickness of the semiconductor material SM to form the thin layer 22 of the doped semiconductor material shown in FIG. 4d. Here, the doped semiconductor material thin layer 222a and the doped semiconductor material thin layer 22 are, for example, composed of the same doped type semiconductor material SM to define the first type doped semiconductor layer 222. As can be seen from Figure 4d, the light collimating structure 224 is embedded in the first doped semiconductor layer 222. Referring to FIG. 4e, an active layer 226 and a second type doped semiconductor layer 228 are formed on the first type doped semiconductor layer 222, wherein the active layer 226 is located in the first type doped semiconductor layer 222 and the second type. The semiconductor layers 228 are doped to form a light emitting structure layer 230. The active layer 226 is, for example, a multiple quantum well (MQW) layer, but is not limited thereto. Further, the materials of the first type doped semiconductor layer 222 and the second type doped semiconductor layer 228 are, for example, an n-type doped semiconductor material and a p-type doped semiconductor material, respectively, or vice versa. The n-type doped semiconductor material and the p-type doped semiconductor material used in the present embodiment are, for example, n-type gallium nitride and germanium-type gallium nitride, respectively. However, in other embodiments, the n-type doped semiconductor material and the germanium-type semiconductor material may be other semiconductor materials of different types, such as GaN (GaAIN), indium gallium nitride (GalnN). Other melon-V family nitrogen compounds. Then, referring to FIG. 4f', the contact layer 232 and the reflective layer 234 are sequentially formed on the light-emitting structure layer 230, and the stack of the light-emitting structure layer 230, the contact layer 232, and the reflective layer 234 is patterned into a plurality of arrays. Miniature LED 236. Here, the material of the reflective layer 234 may be 201227942 aluminum, silver, gold or a combination of the above materials, and the contact layer 232 may be made of nickel/gold, nickel/aluminum/silver, nickel/silver or the like. Accordingly, a protective layer 238 is formed to cover the side surfaces of the micro-light-emitting diodes 236, and electrodes 24 are formed on the reflective layer 234 of each of the micro-light-emitting diodes 236. In the present embodiment, the contact layer 232 is, for example, an ohmic contact layer, and the reflective layer 234 is, for example, a metal reflective layer. Therefore, in addition to providing reflection, the reflective layer 34 can also provide electrical conduction. In addition, the contact layer 232 is disposed between the reflective layer 234 and the second type doped semiconductor layer 228, so that the doping pattern of the contact layer can be the same as that of the second type doped semiconductor layer 228. In particular, the first type doped semiconductor layers 222 of these miniature light emitting diodes 236 are, for example, partially connected together. That is, the first type doped semiconductor layer 222 is not completely broken during the patterning process but is a continuous film layer. Therefore, the protective layer 238 covers only a portion of the side surface of the first type doped semiconductor layer 222, the side surface of the active layer 226, the side surface of the second type doped semiconductor layer 228, the side surface of the contact layer 232, and the reflection The side surface of layer 234 and the reflective layer 234 are remote from a portion of the upper surface of the contact layer. Then, referring to FIG. 4g, a bonding process is performed to bond the electrodes 240 on each of the micro LEDs 236 to another substrate 242, wherein the electrodes 240 are bonded to the substrate 242, for example, by metal contacts 244, and the metal contacts 244 may be Metals such as gold, copper, tin, indium, or stacked combinations or alloys thereof. In the present embodiment, the substrate 242 is, for example, a germanium substrate provided with circuit elements (e.g., metal oxide semiconductor elements, transistors, etc.). 201227942 Next, in FIG. 4h, the substrate 220 is removed from the micro-light-emitting diode 236, and the method of removing the substrate 22〇 may be a laser stripping method. After the substrate 220 is removed from the micro-light-emitting diode 236, the surface of the first-type doped semiconductor layer 222 away from the active layer 226 is exposed, for example. Subsequently, referring to Fig. 4i, a transparent conductive layer 246 is formed on the exposed first type doped semiconductor layer 222 to constitute an array of light emitting cells. The material of the transparent conductive layer 246 includes indium tin oxide (Indium Zinc®, ιτ〇), indium zinc oxide (Indium Zinc 0xide, ΙΖΟ), aluminum zinc oxide (Aluminium Zinc Oxide, AZO), doped gallium Zinc oxide (Gallium d〇ped zinc Oxide, GZO), nickel/gold, and the like. The light-emitting unit array 200 is composed of a plurality of micro-light-emitting diodes 236 disposed on the substrate 242, that is, each of the micro-light-emitting diodes 236 is a light-emitting unit. In the present embodiment, the substrate 242 Circuit elements are disposed thereon, so that each of the micro-light-emitting diodes 236 can be independently driven to emit light of different brightness and/or color, so that the light-emitting unit array 200 can directly display images. In other words, the light emitting unit array 200 can be directly used as a display panel instead of only providing a light source. In this embodiment, a portion of the first type doped semiconductor layer 222 , the active layer 226 , and the second type doped semiconductor layer 228 of each of the micro LEDs 236 are sandwiched between the reflective layer 234 and the light collimating structure 224 . . The light line collimating structure 224 has the property of reflecting light, and the active layer 226 that emits light is located between the reflective layer 234 and the light collimating structure 224. Therefore, the thickness of the miniature light-emitting diode 236 is designed under suitable conditions, and the reflective layer 234 and the light collimating structure 224 can form a resonant cavity such that the light emitted by the active layer 2012 226 226 is reflected by the reflective layer 234 and the light collimating structure 224. Resonance occurs and collimates. In one embodiment, the thickness L of the micro-light-emitting diode 236 between the reflective layer 234 and the light collimating structure 224 is consistent with the emission wavelength λ of the active layer 226: L=n/2X, n is a positive integer and 3< η < 20. At this time, the light emitted by the active layer 226 can collimate the micro-light-emitting diode 236. Specifically, Fig. 5a and Fig. 5b are respectively a far field distribution map of a conventional micro light emitting diode and a far field distribution diagram of the micro light emitting diode of the present embodiment. 5a and 5b, the far-field distribution of the conventional micro-light-emitting diode is approximately circular (the light-emitting half-angle is in the range of < ± 60 ◦), and the food-substance light-emitting body of the present embodiment The far field distribution of 236 is relatively narrow (the exit half angle can be in the range of < soil 30°). It can be seen that the light-emitting diode 236 of the present embodiment has a relatively large light-emitting angle, that is, a better degree of collimation. In addition, FIG. 6 illustrates the distribution of the far-field light intensity exhibited by the miniature light-emitting diodes in the light-emitting unit array according to the first embodiment of the present invention at different viewing angles. As can be seen from Fig. 6, the light emitted from the micro-light-emitting diode 236 of the present embodiment is concentrated near the 0-degree angle of view under the condition of being equipped with a microlens. Compared to the conventional design illustrated in Fig. 3, the design of this embodiment substantially reduces the intensity of the light of group B and group C in Fig. 3. That is, the micro-light-emitting diode 236 of the present embodiment clearly has a relatively collimated light-emitting effect' and greatly reduces the intensity of the obliquely emitted light. Further, Table 1 shows the light-emitting efficiency of the light-emitting unit array constituted by the micro-light-emitting diode of the present embodiment and the conventional micro-light-emitting diode. 11 201227942 Pitch between miniature light-emitting diodes Size of miniature light-emitting diodes - Light beam shape - '丨 with microlens array----_ Light-emitting rate 30μιη 15μπι Conventional miniature light-emitting diode ( Divergence angle 120〇) 丨丨丨丨—No 6.2% The miniature light-emitting diode of this embodiment (diverging angle 60°) No 8-6% Conventional miniature light-emitting diode (diverging angle 120°) 21.7% This implementation The miniature light-emitting diode (diffusion angle 60°) is 38.9%. As can be seen from Table 1, the true miniature light-emitting diode 236 has better light output than the conventional design regardless of whether it is matched with the microlens array. 7 is a schematic diagram of the light emitting unit array of the first embodiment applied to the projection system. Referring to Fig. 7, the projection system 3 includes a light emitting unit array 200, a microlens array 3〇2, and a projection lens 3〇4. The micro mirror array 302 is disposed, for example, on the light emitting unit array 2A, wherein the microlens array 302 is composed of a plurality of micro lenses 3〇2A, and each of the micro lenses 302A corresponds to one micro light emitting diode 236. The projection lens 3〇4 is disposed on the optical path of the display light of the light-emitting unit array 200 (display unit array). The micro-light-emitting diodes 236 in the light-emitting unit array 200 can independently emit light of different colors and/or intensities as the pixels for displaying the pupils, so that the light-emitting unit array 2 can be regarded as a display cell array. 12 201227942 Therefore, in this embodiment, the projection system and system need to include an additional display panel to contribute to the overall volume. Further, as is apparent from Figs. 5a, 5b, 6 and Table 1, the light-emitting unit array has a light-collecting effect of high collimation and high efficiency, so that the projection system _ does not easily have an optical crosstalk phenomenon and has an ideal image quality. In other words, applying the actual light-emitting unit array 200 to the projection pattern can provide a more desirable image quality. Tian Ran does not limit the design of the light-emitting unit array 200 to the projection system 300. The light-emitting unit array 2 can also be applied to other products or other design towels that need to be collimated. In addition, the design of the present embodiment is such that the light collimating structure 224 of the micro LED 236 is buried in the first-type doped semiconductor layer 222, but in other embodiments, the light collimating structure 224 may have other configurations. the way. 8a to 8e are schematic diagrams showing a manufacturing process of an array of light emitting units according to a second embodiment of the present disclosure. It is to be noted that the materials used in the components of the embodiment and the method of fabricating the same can be referred to the contents of the first embodiment, and will not be described again. Referring to Fig. 8a, a plurality of light emitting structures 420, a plurality of contact layers 428, a plurality of reflective layers 43A, a plurality of first electrodes 440, a plurality of second electrodes 45A, and a protective layer 46A are formed on the substrate 41A. Each of the light emitting structures 42A includes a first type doped semiconductor layer 422, an active layer 424, and a second type doped semiconductor layer 426 which are sequentially stacked outwardly from the substrate 410, and the contact layer 428 is disposed on the second type doped semiconductor layer. At 426, the first type doped semiconductor layers 422 of the light emitting structures 420 are partially joined together to form a continuous film layer. Each of the reflective layers 430 is disposed on one of the contact layers 428. Each of the first electrodes 440 is disposed on one of the reflective layers 430, and each of the 13 201227942 second electrodes 450 is in contact with the first type doped semiconductor layer 422 of one of the light emitting structures 42A. The protective layer 460 covers the side = face of the light emitting structure, the side surface of the contact layer 428, and the side surface of the reflective layer 43A. In the present embodiment, substrate 410 is, for example, a sapphire substrate or other suitable epitaxial substrate. Next, referring to Fig. 8b, a bonding process is performed such that the first electrode 44A and the second electrode 450 are bonded to the substrate 470. Further, the gap between the light emitting structures 42A may be filled with the filling layer 480. The substrate 470 is, for example, a germanium substrate on which a circuit component 472 is disposed, and the circuit component 472 is electrically connected to the first electrode 440 and the second electrode 450 to drive the light emitting structure 42. Here, the light emitting structures 420 are independently driven. It can emit light of different brightness and/or color, so it can be regarded as a pixel for displaying the surface. Also, in the case of 疋δ, the array of light-emitting structures 420 can be regarded as a pixel array or a display cell array to display a facet. Then, referring to FIG. 8c, the substrate 410 is stripped to expose a continuous film layer composed of the first type doped semiconductor layer 422, and is formed on the surface of the continuous film layer sequentially with reference to FIG. 8 (1 and FIG. 8e). The transparent conductive layer 49A and the light collimating structure 492 constitute the light emitting unit array 4〇〇, wherein the light emitting structure 420, the contact layer 428, the reflective layer 430, the transparent conductive layer 490, and the light collimating structure 492 together constitute a plurality of miniature light emitting The diode 494. In this embodiment, the light collimating structure 492 is a distributed distributed Bragg reflection layer or an omnidirectional reflection layer continuously formed on the light emitting structures 420, and each of the light emitting structures 420 is sandwiched by the light collimation. Between the structure 492 and the reflective layer 430. Since the light collimation structure 492 has a reflection effect, when the thickness of the illumination structure 201227942 420 is set under suitable conditions, the light emitted by the illumination structure 42 can be in the light collimation structure 492 and the reflective layer. Resonance occurs between 430 to achieve near-minus the light-emitting effect equivalent to the collimation of the first embodiment. In other words, the light-emitting unit array 4 of the present embodiment is compared with the first embodiment. The light-emitting unit array 200 can have the same advantages (including at least a high-collimation light-emitting effect and a better light-emitting efficiency), and is advantageous for upgrading the projection system when the light-emitting unit array is applied to the projection system 3 of FIG. The imaging quality also helps to reduce the volume of the projection system. FIG. 9a to FIG. 9g are not schematic diagrams showing the manufacturing process of the light-emitting unit array according to the third embodiment. Referring to FIG. 9a, the substrate 51 is sequentially formed. The first-type doped semiconductor layer 522, the active layer-and the second-type impurity-conducting layer 526. The substrate 51G is, for example, a sapphire substrate or other substrate which can be crystallized. The first-type doped semiconductor layer 522 is, for example, a semiconductor. The layer '' and the second type semiconductor layer 526 are, for example, p, "-conductor layers. In the present embodiment, the (n) n-type doped semiconductor material type doped semiconductor material is, for example, n-type nitriding and ρ coarse L, respectively. However, in other embodiments, the n-type doped semiconductor material conductor material conductor is incident on the other half of the different states, such as gallium nitride (GaA1N), indium nitride ((ΜηΝ), etc. In addition, the active layer 524 may be a multiple quantum device. In addition to the external reference layer, the second type doped semiconductor layer 526 is on the mesh #momΓ conductive layer 530 and the metal mesh 540, wherein the metal, 祠. 540 has a plurality of openings 542.

S 15 201227942 Then 'please refer to FIG. 9 c to form a plurality of light collimating structures 550 ' in the openings 542 of the metal grid ο , wherein each of the light collimating structures 55 〇 may be a distributed Bragg reflector or an omnidirectional mirror. Next, referring to FIG. 9d, the metal mesh 540 and the light collimating structure 550 are bonded to the other substrate 57 through a filling layer 56, wherein the substrate 570 is a transparent substrate. After the bonding step, The substrate 510 is stripped of the first type doped semiconductor layer 522 as shown in Fig. %. Then, as shown in Fig. 9f, the first type doped semiconductor layer 522, the active layer 524, and the second type doped semiconductor layer 526 are patterned into The plurality of light emitting structures 52A, the protective layer 58 is formed on the side surface of the light emitting structure 520, and the electrode 582 is formed on the first type doped semiconductor layer 522 of the light emitting structure to form a plurality of miniature light emitting bodies M. The light-emitting structure 520, the transparent conductive sound, the entire network, and the light collimation are disposed between the electrode 582 of the diode M and the transparent substrate 570. The material of the second electrode 3 may be metal, so the electrode 582 may be The reflection layer and the conductive layer can be regarded as a reflection layer at the same time. The collinear structure 55 〇 is composed of a distributed Bragg reflector or an omnidirectional mirror, so that the thickness of the light-emitting structure 520 is suitable, The light emitted by the light emitting structure 52A will resonate between the electrode 582 and the light collimating structure 55. Thus, as described in the first embodiment, the miniature light emitting diode M provides a collimated light emitting effect and The light-emitting efficiency is ideal. After that, the electrodes 582 on the micro-light-emitting diodes are bonded to the substrate through a plurality of metal contacts 584 to form the light-emitting unit array 500, wherein the substrate 590 has a plurality of M 〇 s circuit 16 201227942 element 592. In addition, the gap between the miniature light-emitting diodes M may be filled with another filling layer 586. In this embodiment, each of the micro-light-emitting diodes Μ may be correspondingly The circuit component 592 is driven, so that different miniature light-emitting diodes can emit light of different brightness and/or color to provide a display function. The miniature light-emitting diodes of the example can be regarded as pixels for displaying the pupils. Therefore, the light-emitting unit array 500 can have the same function as the light-emitting unit array 2 of the projection system 3 shown in FIG. In addition, since each of the micro-light-emitting diodes includes an electrode 582 having a reflective property and a light collimating structure 55A, the stage emitted by the micro-light-emitting diode 可以 can resonate and collimate between the two elements. For the purpose of the grounding, refer to FIG. 5a, 5b and FIG. 6H in the first embodiment. Therefore, the 'light-emitting unit array 5' may have the light-emitting unit array 2〇〇. When the luminous single (10) is applied In the projection system shown in Figure 7, 'helps to reduce the overall volume and improve image quality. The above-mentioned actual _ is based on the use of the ship, and is limited to invention. Any member that can use r if or other similar features can form a resonant cavity in a miniature light-emitting diode, and the collimation of the device after the action is in accordance with the invention is not limited to the use of resonance. The technical section of the polar body is straight out of the light effect. Accordingly, the eight embodiments further illustrate the spirit of the invention. Figure 10 is a view showing the hair of the fourth embodiment of the present disclosure

Schematic diagram of the lens barrier. Please refer to the figures ', A, and FIG. 10, in this embodiment, the microlens

S 17 201227942 = 歹 J 7〇〇 configuration, the light-emitting unit array is fine, and has a plurality of micro-transmissions. The light emitting cell array, J 600 includes a plurality of arrays arranged on the substrate 610 pole body 62. And each of the micro-light-emitting diodes 62 is electrically connected to the two U-electrode 64G and the transparent conductive layer (10), and is external. The individual electrodes _ are bonded to the circuit component 612 of the substrate 610, for example, via corresponding contacts. Specifically, each of the micro-light emitting diodes 62A includes a reflective layer 622, a contact layer 624, a light emitting structure 626, and a light collimating structure 628. The light emitting structure 626 includes a first type of doped semiconductor layer 626 eight, an active layer 626B, and a second impurity conductive layer απ, and a second-type doped semiconductor layer 626A and a second type doped semiconductor layer. 626c is an n-type semiconductor material and a germanium-doped semiconductor material, respectively, or vice versa. In the present embodiment, the (iv) n-type doped semiconductor material and the p-type doped semiconductor material are, for example, type 11 gallium nitride and germanium type gallium nitride, respectively. However, in other embodiments, the n-type doped semiconductor material and the p-type doped semiconductor material may be other semiconductor materials that are non-domain-type, such as GaN (GaAIN), indium gallium nitride (GaInN). And other m_v group nitrogen compounds. Additionally, the light collimating structure 628 has a plurality of pockets 628A. Each recess 628A may have a depth of 5 〇 nm to 25 〇 nm. In one embodiment, the recess f28A may optionally be filled with other materials, filled with a dielectric material or filled with a distributed Bragg mirror. And the refractive index of the filled material is different from the refractive index of the second type doped semiconductor layer 626C. At this time, the light collimating structure 628 can change the optical path of the light emitted by the light emitting structure 626, so that the micro light emitting diode 620 has a collimated light emitting effect. Specifically, the light-emitting unit array 600 may have the functions and advantages of the light-emitting unit array 200 of the first embodiment. In the present embodiment, the recess 628A of the light collimating structure 628 is presented as a photonic crystal structure layer. That is to say, the present embodiment can utilize the design of the photonic crystal structure to adjust the light-emitting effect of the miniature light-emitting diode 620 to achieve an ideal light-collecting collimation. In general, the arrangement of the photonic crystal structure is periodically related to the wavelength of the light emitted from the micro-light-emitting diode 62 and the angle of light to be obtained. Figure U is a dispersion diagram of a miniature light-emitting diode, which is expressed as a relationship between the ratio of the light-emitting light vector of the light emitted by the micro-light-emitting diode to the wavelength of the photonic crystal structure corresponding to the wavelength of the light. In Fig. u, Γ is expressed as the direction in which the light vector is parallel to the normal direction of the light exit surface, that is, the collimated light exit direction (zero angle). χ and Μ respectively indicate the two directions of the parallel exit surface. It can be seen from the relationship of the graph η that the light emitted by the Μ-type light-emitting diode has many nodes corresponding to the Γ in the dispersion relation diagram. When the ratio of the pitch of the photonic crystal structure corresponding to the wavelength of the light falls on these nodes, it means that the micro-light emitting diode can have a collimated light-emitting effect. Therefore, the relationship between the photonic crystal structure and the wavelength emitted by the known micro-light emitting diode is used to determine the pitch of the photonic crystal structure, so that the micro-light emitting diode has a collimated light-emitting effect. That is to say, according to the nodes in FIG. 11, the pitch of the recesses 628Α of the light collimating structure 628 in FIG. 1 can be determined to make the micro-lighting diode 620 have an ideal light-emitting effect to reduce the light-emitting unit. Optical crosstalk occurs between adjacent micro-light emitting diodes 620 in the array 6A. FIG. 12 is a schematic diagram of a light unit array according to a fifth embodiment of the present disclosure.

S 19 201227942 Schematic diagram of a microlens array. Referring to FIG. 12, the design of the embodiment is substantially the same as that of the four embodiments. Therefore, the same components in the two embodiments will be denoted by the same reference numerals, and will not be further described herein. Specifically, the main difference between the present embodiment and the fourth embodiment is that in the light-emitting unit array 8 of the present embodiment, the light collimating structure 628 in each of the micro-light-emitting diodes 820 is a photonic crystal structure layer 'and Each of the micro-light-emitting diodes 82 has a photonic crystal structure layer 810 in addition to all the components of the micro-light-emitting diode 620, and is disposed on the light-emitting structure 626 and the reflective layer of each of the micro-light-emitting diodes 82A. Between 622. That is, each of the micro-light-emitting diodes 820 of the present embodiment has two photonic crystal structure layers (the photonic crystal structure layer 81 and the light-collimation structure 628 having the photonic crystal structure layer as an embodiment), and the light-emitting structure 626 Located between the two photonic crystal structure layers. The photonic crystal structure layer 810 likewise has a plurality of recesses 81 〇 A, and the pitch of the recesses 810A can be determined with reference to the relationship presented in FIG. In addition, the recess 628A can be selectively filled with other materials or filled with a reflective material, wherein the reflective material filled in the recess 810A can be the same as the reflective layer 622. That is, the reflective material filled in the recess 810A may be integrally formed with the reflective layer 622, but the disclosure is not limited thereto. The photonic crystal structure layer 810, like the light collimation structure 628, can change the light path of the light emitted by the micro-light-emitting diode 820 to help the micro-light-emitting diode 820 have a collimated light-emitting effect. Therefore, the light-emitting unit array 8 can have the same effects and advantages as those of the light-emitting unit array 2 of the first embodiment, and can be applied to a projection system. In summary, the present disclosure is disposed in the micro-light-emitting body of the light-emitting unit_ using a tracking structure having a reflection characteristic or having a path characteristic of changing light 20 201227942. Therefore, each of the micro-light-emitting diodes of the illuminating unit array can be σο. 匕 ,, when the illuminating early-earth array of the present disclosure is in accordance with the projection (four) system, the illuminating single column can directly display the image 'no additional display panel And to achieve the effect of reducing the overall volume. At the same time, the "lighting unit" is less prone to optical crosstalk and helps to improve the imaging quality of the projection system. Further, the light-emitting unit array has a good light-emitting efficiency and also contributes to superior imaging quality of the projection system. The present disclosure has been disclosed in the above embodiments, but it is not intended to limit the disclosure, and any person skilled in the art can make some changes and refinements without departing from the spirit and scope of the disclosure. The scope of protection of this disclosure is subject to the definition of the scope of the patent application. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a known projection system using a miniature light-emitting diode array display type light source. 2 is a ray tracing diagram of a miniature light emitting diode array in the projection system of FIG. 1. 3 is a diagram showing the far field light intensity distribution of the miniature light emitting diode array in the projection system of FIG. 1. 4a to 4i illustrate a method of fabricating an array of light emitting cells according to a first embodiment of the present disclosure. 5a and 5b are respectively a far-field distribution diagram of a conventional micro-light-emitting diode and a far-field distribution diagram of the micro-light-emitting diode of the present embodiment.

S 21 201227942 FIG. 6 is a diagram showing the distribution of the far-field light intensity exhibited by the micro-light-emitting diode in combination with the micro-lens in the light-emitting unit array according to the first embodiment of the present disclosure. FIG. 7 is a schematic diagram of a light emitting unit array according to a first embodiment of the present disclosure applied to a projection system. 8a to 8e are schematic diagrams showing the manufacturing process of the array of light emitting units according to the second embodiment of the present disclosure. 9a to 9g are schematic diagrams showing a manufacturing process of an array of light emitting units according to a third embodiment of the present disclosure. FIG. 10 is a schematic diagram of a light emitting unit array and a microlens array according to a fourth embodiment of the present disclosure. η Figure 11 is a diagram showing the relationship between the light-emitting diodes of the micro-light-emitting diodes and the ratio of the wavelengths of the light-emitting light rays emitted by the micro-light-emitting diodes to the wavelengths of the photonic crystal structures. FIG. 12 is a schematic diagram of a light-emitting unit array with a microlens array according to a fifth embodiment of the present disclosure. [Main component symbol description] 10, 220, 242, 410, 470, 510, 570, 590, 610: substrate 100, 300: projection system 110: micro LED array 120, 302, 700: microlens array 130, 304: projection lens 22 201227942 200, 400, 600, 800: light emitting unit array 222, 422, 522, 626A: first type doped semiconductor layer 222a, 222b: doped semiconductor material thin layer 224, 492, 550, 628: Light collimating structure 226, 424, 524, 626B: active layer 228, 426, 526, 626C: second type doped semiconductor layer 230: light emitting structure layer 232, 428, 624: contact layer 234, 430, 622: reflective layer 236, 494, 620, 820, Μ: miniature light-emitting diodes 238, 460, 580: protective layers 240, 582, 640: electrodes 242: substrates 244, 584: metal contacts 246, 490, 530, 650: transparent conductive Layers 302Α, 702: microlenses 420, 520, 626: light emitting structure 440: first electrode 450: second electrodes 472, 592, 612: circuit elements 480, 560, 586: fill layer 540: metal grid 542: opening 628Α , 810Α: pocket

23 201227942 660 : Contact 810 : Photonic crystal structure layer A, B, C : Group G: Gap L : Thickness SM : Semiconductor material 24

Claims (1)

201227942 VII. Patent application garden: 1. An array of light-emitting units, comprising: a plurality of miniature light-emitting diodes, the array is arranged on a substrate, and each of the miniature light-emitting diodes comprises: a reflective layer; The light emitting structure includes a first type doped semiconductor layer, an active layer, and a second type doped semiconductor layer stacked in sequence; and a first light collimating structure, wherein at least A portion of the first doped semiconductor layer, the active side layer, and the second doped semiconductor layer are sandwiched between the reflective layer and the light collimating structure. 2. The array of light-emitting units according to claim 1, wherein the light collimating structure of each of the micro-light-emitting bodies comprises a distributed Bragg mirror or an omnidirectional mirror. 3. The light-emitting unit array of claim 2, wherein the light collimating structure of each of the five-type light-emitting diodes is buried in the first-type doped semiconductor layer. 4. The illuminating unit array according to claim 2, wherein a thickness L of the illuminating structure of each of the micro illuminating diodes between the ray collimating structure and the reflective layer and an illuminating wavelength of the active layer It also conforms to L = n / 2 λ, η is a positive integer and 3 < η < 2 〇. 5. The array of light-emitting units of claim 1, wherein the light collimating structures of the miniature light-emitting diodes are connected in a continuous distributed Bragg reflector layer. 6. The light-emitting unit array of claim 1, wherein the light collimating structure of each of the micro-light emitting diodes has a plurality of recesses. 7. The array of light-emitting units of claim 6, further comprising a plurality of distributed Bragg mirrors, each of the distributed Bragg mirrors being filled in one of the pockets. 8. The array of light-emitting units of claim 6, wherein the recesses of the light collimating structure are periodically arranged to form a first photonic crystal structure layer. 9. The array of light-emitting units of claim 8, wherein the recesses of the first photonic crystal structure layer are filled with a dielectric material. 10. The light-emitting unit array of claim 8, wherein each of the micro-light-emitting diodes further comprises a second photonic crystal structure layer, the light-emitting structure disposed on the micro-light-emitting diode and the reflective layer between. 11. The array of light-emitting units according to claim 1, wherein the photonic crystal structure layer has a plurality of recesses filled with a reflective material, and the reflective material and the reflective layer are of the same material. 12. A projection system, comprising: a display unit array comprising a plurality of miniature light emitting diodes arranged in an array on a substrate and each of the miniature light emitting diodes comprises: a reflective layer; a light emitting structure, configured On the reflective layer, the light emitting structure comprises a first type doped semiconductor layer, an active layer and a second type doped semiconductor layer stacked in sequence; and a first light collimating structure, wherein at least part of the first a type doped half 26 201227942 conductor layer, the active layer and the second type doped semiconductor layer are sandwiched between the reflective layer and the light collimating structure; and a projection lens group, the display light of the display unit array On the light path. 13. The projection system of claim 12, wherein the light collimating structure of each of the miniature light emitting diodes comprises a distributed Bragg reflector or an omnidirectional mirror. The projection system of claim 13, wherein the light collimating structure of each of the micro LEDs is embedded in the first type doped semiconductor layer. The projection system of claim 13, wherein the light-emitting structure of each of the micro-light-emitting diodes has a thickness L between the light collimating structure and the reflective layer and a light emission of the active layer The wavelength a corresponds to: L = n / 2 λ ' η is a positive integer and 3 < n < 2 〇. 16. The projection system of claim 12, wherein the light collimating structure of each of the micro-light emitting diodes has a plurality of recesses. 17. The projection system of claim 1 further comprising a plurality of distributed Bragg mirrors, each of the distributed Bragg mirrors being filled in one of the pockets. 18. The projection system of claim π, wherein the recesses of the s-light collimating structure are periodically arranged to form a first photonic crystal structure layer. 19. The projection system of claim 18, wherein the recesses of the first photonic crystal structure layer are filled with a dielectric material. The projection system of claim 18, wherein each of the micro-light-emitting diodes further comprises a second photonic crystal structure layer, the light-emitting structure disposed on the micro-light-emitting diode and the Between reflective layers. 21. The projection system of claim 20, wherein the second photonic crystal structure layer has a plurality of recesses filled with a reflective material, and the reflective material and the reflective layer are of the same material. 22. The projection system of claim 12, further comprising a microlens array of a plurality of microlenses, each of the lenses being disposed on one of the miniature light emitting diodes. 28