CN115016213B

CN115016213B - Optical engine for realizing Micro-LED colorized projection

Info

Publication number: CN115016213B
Application number: CN202210837911.4A
Authority: CN
Inventors: 陈恩果; 严银菓; 黎垚; 江昊男; 叶芸; 徐胜; 郭太良
Original assignee: Fuzhou University
Current assignee: Fuzhou University
Priority date: 2022-07-16
Filing date: 2022-07-16
Publication date: 2023-09-29
Anticipated expiration: 2042-07-16
Also published as: CN115016213A

Abstract

The application provides an optical engine for realizing Micro-LED colorized projection, which comprises a Micro-LED chip, a driving circuit substrate, a Micro lens array, a quantum dot color conversion film, a color combining prism and a projection objective. The Micro-LED chip array is arranged on the driving circuit substrate, the quantum dot color conversion film is tightly attached to the upper part of the Micro-LED chip array, and the Micro-lens array is arranged on the quantum dot color conversion film and corresponds to the Micro-LED chip array one by one. The application can realize full-color projection of Micro-LED single chip by combining colors at any angle, reduces the cost of projection colorization, and has larger flexibility and smaller volume.

Description

Optical engine for realizing Micro-LED colorized projection

Technical Field

The application relates to the technical field of semiconductor light-emitting devices, in particular to an optical engine for realizing Micro-LED colorized projection.

Background

The projection technology is changed in three generations, the first generation adopts a cathode ray tube as an imaging device, fluorescent powder in the device is amplified and converged by a light emitting system under the action of high voltage, and a color image is displayed on a screen. The second generation projection technology adopts a liquid crystal light plate to carry out image modulation, and the image is transmitted and displayed through a projection system. With the improvement of the comfort requirements of people on products, the projection technology has been developed to the aspects of high brightness, high quality, microminiature and the like on the basis of the second generation technology. Among them, the miniature projector is the main development direction of the third generation projector, it has small, display size big, light energy utilization rate high grade characteristic. The most widely used projection systems today are liquid crystal on silicon (Liquid Crystal on Silicon, LCOS) and digital light processing (Digital Light Processing, DLP) systems. Because the display units of the two systems are not actively luminous, the utilization rate of light is low, the production cost of the DMD is high, and LCOS is difficult to perform good heat dissipation. In recent years, micro-LED technology, which is regarded as a new generation of display panel technology, has received attention. Micro-LED displays are mainly based on inorganic gallium nitride based (GaN) light emitting diodes, and compared with Liquid Crystal Displays (LCDs) and Organic Light Emitting Diode (OLED) displays, micro-LED displays have many advantages of self-luminescence, high contrast, high resolution, high reliability, long life, low power consumption, etc., compared with other display technologies. Micro-LED display is considered to be a new generation display technology that will subvert the traditional. As a novel display technology, the Micro-LED has the characteristics of ns-level response performance, stable material performance, high reliability, good luminous efficiency, high color purity and the like. Micro-LEDs are superior to OLEDs in various indexes of light efficiency and contrast, have a complete opportunity to replace the OLEDs only in terms of technology, and are expected to become a third-generation display technology for promoting display quality improvement after the OLEDs. The Micro-LED projection has the characteristics of high resolution, high brightness under the chip size, and can be miniaturized, so that great convenience is brought to daily entertainment and work of people, and the development of the Micro-LED projection becomes the development trend of projection technology.

In the prior art, three Micro-LED screens are adopted to independently display three colors of red, green and blue, then the colors are realized through a color combining prism, and the colors are realized through laminated Micro-LEDs, but the luminous effect is not very good, or the backlight technology is adopted, and then the projection is realized through a color filter. At present, the Micro-LED chip is high in price due to the fact that the Micro-LED technology is high in difficulty. The method of realizing colorization by utilizing three Micro-LED screens has the defect of high price, and the problem of wide spectrum bandwidth exists by utilizing a color filter, so that the color gamut of projection equipment is not high enough due to the low color purity of the filtered three primary color light, and the problems of poor flexibility, large volume and the like exist in a light engine in the traditional design.

Disclosure of Invention

In view of the above, the present application is directed to an optical engine for realizing Micro-LED colorized projection, which improves color accuracy and flexibility of the device, and has a small volume.

In order to achieve the above purpose, the application adopts the following technical scheme: an optical engine for implementing Micro-LED colorized projection, comprising: the flexible blue light Micro-LED Micro-display chip provides a self-luminous image source and comprises at least one independent display area, wherein each independent display area is used for displaying different color image sources, each independent area is provided with Micro-LED pixel points with the same number and arrangement interval, and each adjacent area can be folded or bent at an angle of 0-180 degrees; the optical engine is also provided with a color combining device and a projection lens, wherein the color combining device is used for combining the images of all the independent display areas into a light path in the same direction to form a color image, and the color image is projected onto a screen through the projection lens.

In a preferred embodiment, the blue light Micro-LED Micro-display chip is specifically a high-density Micro-display chip with a single pixel size within 50 micrometers, each pixel is a separate Micro-LED light emitting unit, and each Micro-LED pixel is addressable and individually driven to light; at least one hinge structure is arranged between adjacent independent display areas of the blue light Micro-LED Micro display chip, and the hinge structure enables the Micro-LED chip to be bent and folded for an alpha angle and keeps a stable state of bending and folding the alpha angle; the hinge structure is provided with two fixing sheets which are respectively positioned at two sides of a crease, the fixing sheets are fixed at the back of a blue light Micro-LED Micro-display chip through an adhesive, the fixing sheet close to one end of the crease is a driving rod with a gear, and the two fixing sheets are connected through a set of gear transmission combination; the pixels taking the crease as the central line do not participate in the image display luminescence.

In a preferred embodiment, the bending or folding angle range between the display areas is alpha, and 0.ltoreq.alpha.ltoreq.90 DEG is satisfied; when alpha=0°, the Micro-LED screen is a flat planar screen; when alpha=90°, two adjacent display areas of the Micro-LED screen are perpendicular to each other.

In a preferred embodiment, the light emitting colors of the Micro-LED chips in each independent display area are different, namely, a Micro-LED chip pixel array emitting a certain color is prepared in each independent area; the quantum dot color conversion scheme is adopted, namely at least one region of the display regions is attached with a quantum dot color conversion pixel film which is used for converting blue light into images of other primary colors, and pixel arrangement on the quantum dot color conversion pixel film is in one-to-one correspondence with Micro-LED pixel arrangement.

In a preferred embodiment, the Micro-LED chip pixel or the quantum dot color conversion pixel film is provided with a collimating microlens array for collimating the pixel light beams emitted by the quantum dot color conversion film, and the collimating microlens array and the pixel form a one-to-one or many-to-one spatial correspondence, and the collimating microlens array is firmly connected with the Micro-LED chip or the quantum dot color conversion film through a certain adhesive.

In a preferred embodiment, when the Micro-LED is blue light, the full-color projection is realized by selecting red and green quantum dot color conversion pixel films between the blue light Micro-LED and the collimating lens array, and the pixel films are clung to the blue light Micro-LED Micro-display chip or the collimating lens array; the quantum dot color conversion film can be pixelated and aligned with blue light Micro-LED pixels and separated by a black matrix, and is prepared by adopting II-VI or III-V semiconductor quantum dot materials, performing sputtering, pad printing or spin coating deposition, annealing treatment, and performing patterning preparation processes such as photoetching, printing, screen printing and the like; the conversion wavelength of the quantum dot color conversion pixel film is 495-780 nm, the half-peak width is less than or equal to 40nm, and the film thickness is less than 15 microns.

In a preferred embodiment, the color combining device is used to achieve color combination of the light emitted from the independent display area, when the Micro-LED Micro-display chip is unfolded or not bent, i.e. α=0° or 0< α <90°, at least three prism combinations are needed to achieve color combination of three primary colors of light, and then: a first prism for totally reflecting the first primary color light image light; the second prism is used for completely transmitting the second primary color light image light, the total reflection first primary color light image light and the third primary color light image light, and the typical form of the second prism is a square X prism formed by splicing four isosceles right angle prisms; a third prism for totally reflecting the third primary color light image light; when the Micro-LED Micro display chip is in the condition that alpha=90 degrees, the first primary color light image light and the third primary color light image light only need to be totally reflected by the second prism; the typical form of the first prism and the third prism is an isosceles right triangle reflecting prism; the isosceles triangle total reflection prism and the X prism are firmly connected through an adhesive among the first prism, the second prism and the third prism.

In a preferred embodiment, the films used for turning the light path of the first prism and the third prism are reflective films made of Ta2O5 and SiO2 materials by adopting an ion-assisted evaporation method; the process mainly comprises the following steps:

s1: washing the coated substrate with absolute ethyl alcohol, and drying with hot air;

s2: controlling the temperature of the substrate to be 200 ℃, controlling the oxygen flow to be 18sccm and the deposition rate to be 0.5-1.5nm/s, and coating the substrate with a film;

s3: and (3) heat treatment, namely placing the substrate in a muffle furnace, heating to 500 ℃, preserving heat for 2 hours, and cooling the substrate along with the furnace.

In a preferred embodiment, if the included angle between the light-emitting optical axis direction of the Micro-LED Micro-display chip and the perpendicular direction of the incident end face of the second prism is β, the optical axis deflection direction should be deflected by β to coincide with the perpendicular direction of the incident end face by the shape design of the first prism and the third prism.

In a preferred embodiment, the projection imaging lens is composed of a conventional lens group or a lens group fused with a polarizing element and a super surface.

Compared with the prior art, the application has the following beneficial effects: the quantum dots are used as the color conversion layer, the quantum dots have the characteristics of wide absorption and narrow emission, the color of the quantum dot color conversion film is purer, higher color accuracy can be brought, and the quantum dot color conversion film has greater flexibility and smaller volume; the application has the greatest characteristics that only one flexible blue light Micro-LED chip is adopted, the independent display of red, green and blue images is realized by dividing the blue light Micro-LED chip into three areas, and the three areas are integrated, and each Micro-LED chip can be independently controlled through a driving circuit substrate, so that the three areas can be divided to realize the problem of colorization by using one Micro-LED, thereby reducing the cost of a projection system; because a flexible Micro-LED chip is used, a curved fold of a certain angle between the three areas can be achieved to achieve a more compact projection system.

Drawings

FIG. 1 is a schematic view of a light engine for realizing Micro-LED color projection when a Micro-LED Micro-display chip is folded or bent at 0 DEG in a preferred embodiment of the present application;

FIG. 2 is a schematic view of a light engine for implementing Micro-LED color projection when the Micro-LED Micro-display chip is folded or bent at 0-90 DEG in a preferred embodiment of the present application;

FIG. 3 is a schematic view of a light engine for implementing Micro-LED color projection when the Micro-LED Micro-display chip is folded or bent at 90 DEG in a preferred embodiment of the present application;

fig. 4 is a schematic diagram of an active addressing driving circuit used in a Micro-LED chip according to a preferred embodiment of the present application.

Reference numerals

The LED light source comprises a 1-driving circuit substrate, a 2-blue light Micro-LED chip array, a 15-projection imaging lens, a 16-red quantum dot color conversion film, a 17-Micro collimation array, an 18-green quantum dot color conversion film, a 101-first primary color total reflection film, a 102-third primary color total reflection film, a 141-X color combining prism, a 142-right triangle total reflection prism and a 143-right triangle total reflection prism.

Detailed Description

The application will be further described with reference to the accompanying drawings and examples.

It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the application. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application; as used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

The advent of Micro light emitting diode (Micro-LED) display technology has enabled projection display devices to become smaller. In other words, each LED pixel in the Micro-LED array can self-emit light, and the image display is realized by precisely controlling the luminous intensity of each LED, namely, the Micro-LED array can directly emit image light. Secondly, besides the characteristics of high brightness, ultrahigh resolution, high color saturation and high luminous efficiency, the Micro-LED is not influenced by water vapor, oxygen or high temperature, so that the Micro-LED has obvious advantages in the aspects of stability, service life, working temperature and the like.

In order to solve the colorization problem of projection display, the application provides a light engine for realizing Micro-LED colorization projection, which can project a colored image. In particular, as shown in fig. 1 to 4, a light engine for implementing Micro-LED colorization projection according to an embodiment of the present application is illustrated, wherein the light engine for implementing Micro-LED colorization projection includes: a blue light Micro-LED chip array 2 and a driving circuit substrate 1, the blue light Micro-LED chip array 2 being electrically integrated on the driving circuit substrate 1 so as to control address lighting of the blue light Micro-LED chip array 2. A red quantum dot color conversion film 16 for converting blue light into red light and green light, a green quantum dot color conversion film 18, and a micro-collimator array 17 for collimating light emitted through the quantum dot color conversion film such that the X-color combining prism 141 receives the collimated light. The right-angled triangle total reflection prism 142 is used for totally reflecting the collimated first primary color light into the X color combining prism 141, and the right-angled triangle total reflection prism 143 is used for totally reflecting the collimated third primary color light into the X color combining prism 141. The first primary color total reflection film 101 is for totally reflecting the first primary color collimated light, and the third primary color total reflection film 102 is for totally reflecting the second primary color collimated light. The X-color combining prism 141 is used for combining the first, second and third primary colors into color image light, reflecting the color image light to the projection imaging lens 15, and then the projection imaging lens 15 performs projection imaging on the color image light.

The Micro-collimating elements of the Micro-collimating array 17 are in one-to-one correspondence with the Micro-LEDs of the blue light Micro-LED chip array 2, that is, one Micro-collimating element in the Micro-collimating array 17 corresponds to one Micro-LED of the blue light Micro-LED chip array 2, so that only one Micro-collimating element exists in the light emitting path of each Micro-LED. The light emitting angle of the Micro-LED chips is overlarge, after the Micro-LED chips are arrayed, light crosstalk interference can be generated by improper chip spacing, or a light emitting dark area among the chips is caused, and by adopting the embodiment, the light source of the Micro-LED chips is controlled in a small angle range by the Micro-collimation element after passing through the quantum dot color conversion film, so that serious crosstalk interference can not be caused among the light sources of the Micro-LED chips, and the defect that the dark area is caused by low edge brightness can be overcome when the middle brightness of the light beam of a single chip is high.

The micro-collimating element of the micro-collimating array 17 is one of a micro-collimating lens, a conical rod, a fresnel lens and a TIR lens. The microcollimator element is firmly connected to the quantum dot color conversion film by some kind of adhesive.

The quantum dot color conversion films (16, 18) are high-performance quantum dots with high water resistance and oxygen characteristics and core-shell structures, the quantum dots are mixed with polymers, scattering particles and the like, and a magnetic stirrer or an ultrasonic machine is adopted to uniformly mix the quantum dots. Next, the glass substrate was cleaned, respectively sonicated with acetone, isopropyl alcohol, and deionized water for 15 minutes, and then blow-dried with nitrogen. And finally, coating a layer of quantum dot slurry with uniform thickness and controllable thickness on a clean glass substrate by using an automatic film coating machine, and heating at 120 ℃ for 30 minutes for curing to form the quantum dot color conversion film.

The Micro-LED chip adopted in the embodiment is a Micro-LED flip chip, the flip structure is realized by adopting a flip technology, and the flip technology is a future development trend. The flip chip structure comprises a sapphire substrate, an N-type semiconductor layer, a light-emitting layer, a P-type semiconductor layer and an electrode from top to bottom, compared with the normal structure, the flip chip structure has the advantages that heat generated at a PN junction in the structure can be directly conducted to a heat sink without passing through the substrate, so that the heat dissipation performance is good, and the luminous efficiency and the reliability of the chip are higher; in the flip structure, the p electrode and the n electrode are both arranged on the bottom surface, so that shielding of emergent light is avoided, and the light-emitting efficiency of the chip is high; in addition, the distance between the electrodes of the flip chip is far, so that the short circuit risk caused by electrode metal migration can be reduced. The packaging density is greatly increased, which is ten times of that of the normal chip, the packaging volume is rapidly reduced, and only 20% -30% of the normal chip is required; the sapphire substrate is peeled off, and the light extraction efficiency is increased.

In the active addressing driving circuit, as shown in fig. 3, each Micro-LED pixel has a corresponding independent driving circuit, and the driving current is provided by a driving transistor.

The full-color projection can be realized by selecting red and green quantum dot color conversion pixel films to be positioned between the blue light Micro-LED chip array 2 and the Micro-collimation array 17, and can be clung to the blue light Micro-LED chip array 2 or the Micro-collimation array 17. The quantum dot film can also assist in collimating light passing through the quantum dot color conversion film by adding a surface microstructure, the microstructure on the surface of the quantum dot color conversion film can be manufactured by an imprinting technology, the imprinting technology is a common method for manufacturing the microstructure, the method has the advantages of simple manufacturing process, short processing time, low cost and the like, and the manufactured microstructure can achieve higher resolution and good consistency.

FIG. 1 is a schematic diagram of a light engine for achieving Micro-LED colorized projection when a blue light Micro-LED Micro-display chip is folded or bent to 0 deg.. The blue Micro-LED chip array 2 is now divided into three areas. Blue light emitted by the blue light Micro-LED chip array is converted into red light and green light by the red and green quantum dot color conversion layers above the first area and the third area which are divided. The second region emits blue light without adding a color conversion layer. The emitted red and green light are reflected into the X-color combining prism 141 under the action of the right-angle triangle total reflection prism 142 and the right-angle triangle total reflection prism 143, and then emitted to the projection imaging lens 15 under the action of the first primary color total reflection film 101 and the third primary color total reflection film 102. Fig. 2 and 3 show two variant embodiments of the light engine architecture for implementing Micro-LED colorized projection according to fig. 1. Specifically, as shown in fig. 2, compared with the light engine structure of fig. 1 for implementing Micro-LED colorization projection, the difference from the blue light Micro-LED chip array 2 in the embodiment of the present application is that: the flexible blue light Micro-LED chip array 2 in the embodiment is divided into at least three independent display areas, each for displaying an image of a different primary color. Each adjacent display area can be folded or bent at an angle of 0-180 degrees, and fig. 2 shows that the Micro-LED Micro display chip of the adjacent display area is folded or bent at an angle of 0-90 degrees, and at this time, the light passing through the quantum dot color conversion film directly enters the X color combining prism 141 through the Micro-collimating array 2. The Micro-collimation array 17 is a collimation array with beta angle beam collimation, is matched with an angle alpha between folded or bent Micro-LED Micro-display chips, alpha and beta are complementary angles, the bending or folding angle range between display areas is alpha and is more than or equal to 0 and less than or equal to 90 degrees, and the alpha is more than or equal to 0 and less than or equal to 90 degrees. The collimating array can enable the first and the third single-primary-color light beams to vertically enter the color combining prism along the normal direction of the prism surface. The acute angle of the right angle triangular total reflection prisms (142, 143) is matched with the bending angle alpha between the blue light Micro-LED Micro display chips, so that the theta angle of the right angle triangular total reflection prisms is equal to the alpha angle. Fig. 3 shows that the Micro-LED Micro display chip in the adjacent display area is folded or bent to 90 °, unlike the adjacent display area which is not folded or bent, the right-angled triangle total reflection prism 142 and the right-angled triangle total reflection prism 143 are not required in fig. 3, and at this time, the light passing through the quantum dot color conversion layer directly enters the X color combining prism 141 through the Micro-collimator array 2.

Claims

1. An optical engine for implementing Micro-LED colorized projection, comprising: the flexible blue light Micro-LED Micro-display chip provides a self-luminous image source and comprises at least one independent display area, wherein each independent display area is used for displaying different color image sources, each independent area is provided with Micro-LED pixel points with the same number and arrangement interval, and each adjacent area can be folded or bent at an angle of 0-180 degrees; the optical engine is also provided with a color combining device and a projection lens, wherein the color combining device is used for combining the images of all the independent display areas into a light path in the same direction to form a color image, and the color image is projected onto a screen through the projection lens;

the blue light Micro-LED Micro display chip is specifically a high-density Micro display chip with a single pixel size within 50 micrometers, each pixel is an independent Micro-LED light-emitting unit, and each Micro-LED pixel is addressable and is driven to light independently; at least one hinge structure is arranged between adjacent independent display areas of the blue light Micro-LED Micro display chip, and the hinge structure enables the Micro-LED chip to be bent and folded for an alpha angle and keeps a stable state of bending and folding the alpha angle; the hinge structure is provided with two fixing sheets which are respectively positioned at two sides of a crease, the fixing sheets are fixed at the back of a blue light Micro-LED Micro-display chip through an adhesive, the fixing sheet close to one end of the crease is a driving rod with a gear, and the two fixing sheets are connected through a set of gear transmission combination; the pixel points taking the crease as the central line do not participate in image display luminescence;

the bending or folding angle range between the display areas is alpha, and the alpha is more than or equal to 0 and less than or equal to 90 degrees; when alpha=0°, the Micro-LED screen is a flat planar screen; when alpha=90°, two adjacent display areas of the Micro-LED screen are perpendicular to each other;

the light-emitting colors of the Micro-LED chips in the independent display areas are different, namely, micro-LED chip pixel arrays emitting a certain color are prepared in each independent area; the quantum dot color conversion scheme is adopted, namely at least one region of the display regions is attached with a quantum dot color conversion pixel film which is used for converting blue light into images of other primary colors, and pixel arrangement on the quantum dot color conversion pixel film is in one-to-one correspondence with Micro-LED pixel arrangement;

the Micro-LED chip pixel or the quantum dot color conversion pixel film is provided with a collimating Micro lens array which is used for collimating pixel light beams emitted by the quantum dot color conversion film, forming a one-to-one or many-to-one space corresponding relation with the pixels, and the collimating Micro lens is firmly connected with the Micro-LED chip or the quantum dot color conversion film through a certain adhesive;

the Micro-collimation array is a collimation array with beta angle beam collimation, is matched with an angle alpha between folded or bent Micro-LED Micro-display chips, alpha and beta are complementary angles, the bending or folding angle range between display areas is alpha and is more than or equal to 0 and less than or equal to 90 degrees, and the alpha is more than or equal to 0 and less than or equal to 90 degrees.

2. The optical engine for realizing Micro-LED colorized projection according to claim 1, wherein when the Micro-LED is blue light, the full-color projection is realized by selecting red and green quantum dot color conversion pixel films to be positioned between the blue light Micro-LED and the collimating lens array, and the pixel films are clung to a blue light Micro-LED Micro-display chip or a collimating lens array; the quantum dot color conversion film can be pixelated and aligned with blue light Micro-LED pixels and separated by a black matrix, and is prepared by adopting II-VI or III-V semiconductor quantum dot materials, performing sputtering, pad printing or spin coating deposition, annealing treatment, and performing patterning preparation processes such as photoetching, printing, screen printing and the like; the conversion wavelength of the quantum dot color conversion pixel film is 495-780 nm, the half-peak width is less than or equal to 40nm, and the film thickness is less than 15 microns.

3. The optical engine for implementing Micro-LED colorized projection according to claim 2, wherein the color combining means is configured to implement color combination of light emitted from the independent display area, and when the Micro-LED Micro-display chip is unfolded or unbent, i.e. α=0° or 0< α <90°, at least three prisms are required to implement color combination of three primary colors of light, then: a first prism for totally reflecting the first primary color light image light; the second prism is used for completely transmitting the second primary color light image light, the total reflection first primary color light image light and the third primary color light image light, and the typical form of the second prism is a square X prism formed by splicing four isosceles right angle prisms; a third prism for totally reflecting the third primary color light image light; when the Micro-LED Micro display chip is in the condition that alpha=90 degrees, the first primary color light image light and the third primary color light image light only need to be totally reflected by the second prism; the typical form of the first prism and the third prism is an isosceles right triangle reflecting prism; the isosceles triangle total reflection prism and the X prism are firmly connected through an adhesive among the first prism, the second prism and the third prism.

4. The optical engine for realizing Micro-LED colorized projection according to claim 3, wherein the films for turning the light path of the first prism and the third prism are reflective films made of Ta2O5 and SiO2 materials by an ion-assisted evaporation method; the process mainly comprises the following steps:

5. The optical engine for realizing Micro-LED colorized projection according to claim 4, wherein an included angle between the direction of the light-emitting optical axis of the Micro-LED Micro-display chip and the direction perpendicular to the incident end face of the second prism is beta, and the optical axis deflection direction is deflected by beta to coincide with the direction perpendicular to the incident end face by the appearance design of the first prism and the third prism.

6. The optical engine for realizing Micro-LED color projection according to claim 5, wherein the projection imaging lens consists of a conventional lens group or a lens group combined with a polarizing element and a super surface.