CN115016213A

CN115016213A - Optical engine for realizing Micro-LED colorized projection

Info

Publication number: CN115016213A
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: 2022-09-06
Anticipated expiration: 2042-07-16
Also published as: CN115016213B

Abstract

The invention 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-combination 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 portion 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 invention can realize full-color projection of the Micro-LED single chip by combining colors at any angle, reduce the cost of projection colorization, and has higher flexibility and smaller volume.

Description

Optical engine for realizing Micro-LED colorized projection

Technical Field

The invention 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 subject to the third generation of revolution, the first generation of projection technology adopts a cathode ray tube as an imaging device, and fluorescent powder in the device is amplified and converged by a light-emitting system under the action of high voltage to display a color image on a screen. The second generation of projection technology uses liquid crystal optical panels for image modulation, and the images are transmitted and displayed by a projection system. With the improvement of the requirement of people on the comfort level of products, the projection technology has developed to the aspects of high brightness, high quality, microminiature and the like on the basis of the second generation technology. The micro projector is the main development direction of the third generation projector, and has the characteristics of small volume, large display size, high light energy utilization rate and the like. The most widely used projection systems are currently Liquid Crystal On Silicon (LCOS) and Digital Light Processing (DLP) systems. Since the display units of both systems are not actively emitting light, the utilization rate of light is low, the production cost of the DMD is high, and the 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 much attention. Micro-LED displays are mainly based on inorganic gallium nitride based (GaN) light emitting diodes, and compared to 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 lifetime, low power consumption, etc. compared to other display technologies. Micro-LED display is considered to be a new generation of 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. The Micro-LED is superior to OLED in various indexes of light efficiency and contrast, and has a complete opportunity to replace OLED only in the technical view, and is expected to become a third generation display technology which promotes the display quality after OLED. The Micro-LED projection technology has the advantages that the Micro-LED projection technology can be more miniaturized by utilizing the characteristics of high resolution and high brightness of the Micro-LED under the size of a chip, great convenience is brought to daily entertainment and work of people, and the development of the Micro-LED projection technology becomes the development trend of the projection technology.

At present, in order to realize colorization in a projection technology, three Micro-LED screens are adopted to independently display three colors of red, green and blue, and then colorization is realized through a color combination prism, and also colorization is realized through laminated Micro-LEDs, but the light-emitting effect is not good, and the full-color projection is realized through a backlight technology and a color filter. At present, the Micro-LED chip is expensive due to the high difficulty of the Micro-LED process. The mode of realizing colorization by utilizing three Micro-LED screens has the defect of high price, the problem of wide spectral bandwidth exists by using a color filter, the color purity of filtered tricolor light is not high, the color gamut of projection equipment is not high enough, and the problems of poor flexibility, large volume and the like exist in the traditional designed light engine.

Disclosure of Invention

In view of the above, an object of the present invention is to provide an optical engine for realizing Micro-LED color projection, which has improved color accuracy and flexibility, and is small in size.

In order to achieve the purpose, the invention adopts the following technical scheme: an optical engine for realizing Micro-LED colorized projection, comprising: the flexible blue light Micro-LED Micro display chip provides a self-luminous image source, the blue light Micro-LED Micro display chip comprises at least one independent display area, each independent display area is used for displaying image sources of different colors, each independent area is provided with Micro-LED pixel points with the same number and arrangement intervals, and each adjacent area can be folded or bent at an angle of 0-180 degrees; the optical engine also comprises a color combination device and a projection lens, wherein the color combination device is used for combining the images of 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 Micro-LED Micro-display chip is embodied as a high-density Micro-display chip with a single pixel size within 50 microns, each pixel is an independent Micro-LED light emitting unit, and each Micro-LED pixel is addressable and 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 at an alpha angle and keeps the Micro-LED chip in a stable state of bending and folding at the alpha angle; the hinge structure is provided with two fixing pieces which are respectively positioned at two sides of a crease, the fixing pieces are fixed on the back of a blue light Micro-LED Micro display chip through an adhesive, the fixing piece close to one end of the crease is a driving rod with a gear, and the two fixing pieces are connected in a transmission combination mode through a set of gear; the pixel points with the crease as the central line do not participate in image display luminescence.

In a preferred embodiment, the range of the bending or folding angle between each display area is alpha, and alpha is more than or equal to 0 and less than or equal to 90 degrees; when alpha is 0 degrees, the Micro-LED screen is a flat plane screen; when alpha is 90 degrees, 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 pixel array of the Micro-LED chips emitting a certain color is prepared in each independent area; and a quantum dot color conversion scheme is adopted, namely at least one of the display regions is attached with a quantum dot color conversion pixel film for converting blue light into images of other primary color light, and the pixel arrangement on the quantum dot color conversion pixel film is in one-to-one correspondence with the Micro-LED pixel arrangement.

In a preferred embodiment, the Micro-LED chip pixels or the quantum dot color conversion pixel film are provided with an array of collimating microlenses for collimating the pixel beams emitted from the quantum dot color conversion film to form one-to-one or many-to-one spatial correspondence with the pixels, the collimating microlenses being firmly connected to the Micro-LED chip or the quantum dot color conversion film by an adhesive.

In a preferred embodiment, when the Micro-LED is blue light, a red and green quantum dot color conversion pixel film is selected to realize full-color projection and is positioned between the blue light Micro-LED and the collimating lens array, and is tightly attached to the blue light Micro-LED Micro display chip or the collimating lens array; the quantum dot color conversion film can be aligned with blue light Micro-LED pixels in a pixelization mode and is separated by a black matrix, the quantum dot color conversion film is made of II-VI or III-V group semiconductor quantum dot materials, is subjected to annealing treatment after sputtering, transfer printing or spin coating deposition, and is obtained by patterning preparation processes such as photoetching, printing, silk-screen printing and the like; the conversion wavelength of the quantum dot color conversion pixel thin 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 combine the light emitted from the independent display regions, and when the Micro-LED Micro-display chip is unfolded or not bent, i.e. α is 0 ° or 0< α <90 °, a combination of at least three prisms is required to combine the three primary colors, then: the first prism is used for totally reflecting the first primary color light image light; the second prism is used for totally transmitting the second primary color light image light and totally reflecting the 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 a condition that alpha is 90 degrees, the first primary color light image light and the third primary color light image light only need to be totally reflected through the second prism; the first prism and the third prism are typically reflective prisms in the form of isosceles right triangles; the first prism, the second prism and the third prism are firmly connected through an adhesive.

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

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

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

s3: and (3) heat treatment, namely, putting the substrate into 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 vertical direction of the incident end surface of the second prism is β, the optical axis deflection direction should be deflected by β to coincide with the vertical direction of the incident end surface by the design of the first prism and the third prism.

In a preferred embodiment, the projection imaging lens is composed of a conventional lens set, or a lens set combining a polarization element and a super surface.

Compared with the prior art, the invention has the following beneficial effects: quantum dots are adopted as a color conversion layer, the quantum dots have the characteristics of wide absorption and narrow emission, and the color conversion film of the quantum dots is purer in color, can bring higher color accuracy, and has higher flexibility and smaller volume; the invention is characterized in that only one flexible blue light Micro-LED chip is adopted, the red, green and blue images are independently displayed by being divided into three regions, the three regions are an integral body, and each Micro-LED chip can be independently controlled by a driving circuit substrate, so that the division of the three regions can be realized to solve the colorization problem by using one Micro-LED, and the cost of the projection system is reduced; because flexible Micro-LED chips are adopted, bending and folding at a certain angle can be realized among the three areas, and a more compact projection system is realized.

Drawings

FIG. 1 is a schematic diagram of a light engine structure for realizing Micro-LED color projection when a Micro-LED Micro display chip is folded or bent at 0 degree according to a preferred embodiment of the present invention;

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

FIG. 3 is a schematic view of a light engine structure for realizing Micro-LED color projection when a Micro-LED Micro display chip is folded or bent at 90 degrees according to a preferred embodiment of the present invention;

fig. 4 is a schematic diagram of an active addressing driving circuit adopted by the Micro-LED chip in the preferred embodiment of the present invention.

Reference numerals

1-a 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 combination prism, a 142-right triangle total reflection prism and a 143-right triangle total reflection prism.

Detailed Description

The invention is further explained below with reference to the drawings and the embodiments.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. 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 example embodiments according to the present application; as used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The advent of Micro light emitting diode (Micro-LED) display technology has allowed projection display devices to become smaller. In other words, each LED pixel in the Micro-LED array can be self-luminous, and image display is realized by accurately controlling the luminous intensity of each LED, namely the Micro-LED array can directly emit image light. 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 invention provides a light engine for realizing Micro-LED colorization projection, which can project colorful images. Specifically, as shown in fig. 1 to 4, a light engine for realizing Micro-LED color projection according to an embodiment of the present invention is illustrated, wherein the light engine for realizing Micro-LED color projection comprises: the LED chip comprises a blue light Micro-LED chip array 2 and a driving circuit substrate 1, wherein the blue light Micro-LED chip array 2 is electrically integrated on the driving circuit substrate 1 so as to control the addressing lighting of the blue light Micro-LED chip array 2. The red light source comprises a red quantum dot color conversion film 16, a green quantum dot color conversion film 18 and a micro-collimation array 17, wherein the quantum dot color conversion film is used for converting blue light into red light and green light, and the micro-collimation array 17 is used for collimating light emitted by the quantum dot color conversion film, so that collimated light is received by the X color combination prism 141. The right-angle triangular total reflection prism 142 is used for totally reflecting the collimated first primary color light to the X color-combination prism 141, and the right-angle triangular total reflection prism 143 is used for totally reflecting the collimated third primary color light to the X color-combination prism 141. The first primary color total reflection film 101 is used for totally reflecting the first primary color collimated light, and the third primary color total reflection film 102 is used 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, and reflecting the color image light to the projection imaging lens 15, and the projection imaging lens 15 performs projection imaging on the color image light.

The Micro-collimating elements of the Micro-collimating array 17 correspond to the Micro-LEDs of the blue light Micro-LED chip array 2 one to one, that is, one Micro-collimating element in the Micro-collimating array 17 corresponds to one Micro-LED in the blue light Micro-LED chip array 2, so that only one Micro-collimating element exists in a light emitting path of each Micro-LED. The light emitting angle of the Micro-LED chip is too large, and after the Micro-LED chip is arrayed, light ray crosstalk interference can be generated at improper chip intervals, or light emitting dark areas among the chips are caused.

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 micro-collimating element is firmly attached to the quantum dot color converting film by some adhesive.

The quantum dot color conversion films (16,18) adopt high-performance quantum dots with high water resistance and oxygen resistance and a core-shell structure, 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, sonicated with acetone, isopropanol, and deionized water for 15 minutes, respectively, and then blown dry with nitrogen. And finally, coating a layer of uniform quantum dot slurry with controllable thickness on a clean glass substrate by using an automatic coating machine, and heating for 30 minutes at 120 ℃ for curing to form the quantum dot color conversion film.

The Micro-LED chip adopted by the embodiment is a Micro-LED flip chip, the flip structure is realized by using a flip process, and the flip process is a future development trend. Compared with a forward mounting structure, 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 in sequence from top to bottom, and 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 light-emitting efficiency and the reliability of the chip are high; in the flip structure, the p electrode and the n electrode are both positioned on the bottom surface, so that the shielding of emergent light is avoided, and the light emitting efficiency of the chip is higher; in addition, the distance between the electrodes of the flip chip is long, so that the short circuit risk caused by the migration of the metal of the electrodes can be reduced. The packaging density is greatly increased and is dozens of times of that of the normally-installed chip, the packaging volume is sharply reduced and is only 20% -30% of that of the normally-installed chip; the sapphire substrate is peeled off, and the light extraction efficiency is increased.

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

The red and green quantum dot color conversion pixel film can be selected to be positioned between the blue light Micro-LED chip array 2 and the Micro-collimation array 17 for realizing full-color projection, and can be tightly attached 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 but not limited to an embossing technology, the embossing 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 structural diagram of a light engine for realizing Micro-LED colorized projection when a blue light Micro-LED Micro-display chip is in a condition of being folded or bent to 0 degrees. The blue Micro-LED chip array 2 is now divided into three regions. 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 divided first and third areas. The second area emits blue light without adding a color conversion layer. The emitted red and green light is reflected into the X color-combination prism 141 under the action of the right-angled triangular total reflection prism 142 and the right-angled triangular 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 colour projection according to fig. 1. Specifically, as shown in fig. 2, compared to the light engine structure of fig. 1 for implementing Micro-LED colorized projection, the difference from the blue light Micro-LED chip array 2 in the embodiment of the present invention is as follows: the flexible blue light Micro-LED chip array 2 in the embodiment is divided into at least three independent display areas, and each independent display area is used for displaying images with different primary colors. Every adjacent display area can be folded or bent at an angle of 0-180 degrees, fig. 2 shows that the Micro-LED Micro display chip in the adjacent display area is folded or bent at an angle of 0-90 degrees, and at this time, light passing through the quantum dot color conversion film directly enters the X color-combining prism 141 through the Micro-collimation array 2. The Micro-collimation array 17 is a collimation array with beta-angle light beam collimation, and is matched with an angle alpha between folded or bent Micro-LED Micro-display chips, the alpha and the beta are complementary angles, the bending or folding angle range between display areas of beta being more than or equal to 0 and less than or equal to 90 degrees is alpha, and the alpha is more than or equal to 0 and less than or equal to 90 degrees. The collimation array can make the first and third monochromatic light beams vertically enter the color-combination prism along the normal direction of the prism surface. Acute angles of the right-angle triangular total reflection prisms (142, 143) are matched with a bending angle alpha between the blue light Micro-LED Micro display chips, so that a theta angle of the right-angle triangular total reflection prisms is equal to an alpha angle. Fig. 3 shows a case where the Micro-LED Micro display chips in adjacent display regions are folded or bent at 90 °, and unlike the case where there is no folding or bending between adjacent display regions, the Micro-LED Micro display chips in fig. 3 do not need the right-angle triangular total reflection prism 142 and the right-angle triangular total reflection prism 143, and at this time, light passing through the quantum dot color conversion layer directly enters the X color combining prism 141 through the Micro-collimating array 2.

Claims

1. An optical engine for realizing Micro-LED colorized projection is characterized by comprising: the flexible blue light Micro-LED Micro display chip provides a self-luminous image source, the blue light Micro-LED Micro display chip comprises at least one independent display area, each independent display area is used for displaying image sources of different colors, each independent area is provided with Micro-LED pixel points with the same number and arrangement intervals, and each adjacent area can be folded or bent at an angle of 0-180 degrees; the optical engine also comprises a color combination device and a projection lens, wherein the color combination device is used for combining the images of 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.

2. The optical engine for realizing Micro-LED colored projection of claim 1, wherein the blue light Micro-LED Micro-display chip is embodied as a high density Micro-display chip with a single pixel size within 50 microns, each pixel is an independent Micro-LED light emitting unit, each Micro-LED pixel is addressable and 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 at an alpha angle and keeps the Micro-LED chip in a stable state of bending and folding at the alpha angle; the hinge structure is provided with two fixing pieces which are respectively positioned at two sides of a crease, the fixing pieces are fixed on the back of a blue light Micro-LED Micro display chip through an adhesive, the fixing piece close to one end of the crease is a driving rod with a gear, and the two fixing pieces are connected in a transmission combination mode through a set of gear; the pixel points with the crease as the central line do not participate in image display luminescence.

3. A optical engine for implementing Micro-LED color projection according to claim 2, wherein the range of bending or folding angles between each display area is α, and satisfies 0 ≦ α ≦ 90 °; when alpha is 0 degrees, the Micro-LED screen is a flat plane screen; when alpha is 90 degrees, two adjacent display areas of the Micro-LED screen are perpendicular to each other.

4. An optical engine for realizing Micro-LED colored projection according to claim 1, wherein the Micro-LED chips in each independent display area emit light with different colors, that is, a pixel array of the Micro-LED chips emitting a certain color is prepared in each independent area; and a quantum dot color conversion scheme is adopted, namely at least one of the display regions is attached with a quantum dot color conversion pixel film for converting blue light into images of other primary color light, and the pixel arrangement on the quantum dot color conversion pixel film is in one-to-one correspondence with the Micro-LED pixel arrangement.

5. An optical engine for implementing Micro-LED color projection as claimed in claim 4, wherein the Micro-LED chip pixels or the quantum dot color conversion pixel film are provided with collimating Micro-lens arrays for collimating the pixel beams emitted by the quantum dot color conversion film to form one-to-one or many-to-one spatial correspondence with the pixels, and the collimating Micro-lenses are firmly connected with the Micro-LED chip or the quantum dot color conversion film through a certain adhesive.

6. The optical engine for realizing Micro-LED colorized projection according to claim 5, wherein when the Micro-LED is blue light, a red and green quantum dot color conversion pixel film is selected for realizing full-color projection and is positioned between the blue light Micro-LED and the collimating lens array, and is tightly attached to the blue light Micro-LED Micro display chip or the collimating lens array; the quantum dot color conversion film can be aligned with blue light Micro-LED pixels in a pixelization mode and is separated by a black matrix, the quantum dot color conversion film is made of II-VI or III-V group semiconductor quantum dot materials, and is obtained through a patterning preparation process such as photoetching, printing, silk-screen printing and the like after being subjected to annealing treatment after sputtering, transfer printing or spin coating deposition; 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.

7. An optical engine for realizing Micro-LED color projection according to claim 6, wherein the color combining device is used to realize color combining of light emitted from independent display areas, and when the Micro-LED Micro-display chip is unfolded or not bent, i.e. α is 0 ° or 0< α <90 °, at least three prisms are required for realizing color combining of tricolor light, then: the first prism is used for totally reflecting the first primary color light image light; the second prism is used for totally transmitting the second primary color light image light and totally reflecting the 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 a condition that alpha is 90 degrees, the first primary color light image light and the third primary color light image light only need to be totally reflected through the second prism; the first prism and the third prism are typically reflective prisms in the form of isosceles right triangles; the first prism, the second prism and the third prism are firmly connected through an adhesive.

8. The optical engine for realizing Micro-LED colored projection of claim 7, wherein the films for turning the light paths of the first prism and the third prism are light reflecting films made of Ta2O5 and SiO2 materials by an ion-assisted evaporation method; the process mainly comprises the following steps:

9. An optical engine for realizing Micro-LED color projection according to claim 8, wherein if the included angle between the light emitting optical axis direction of the Micro-LED Micro-display chip and the vertical direction of the incident end surface of the second prism is β, the optical axis deflection direction should be deflected to coincide with the vertical direction of the incident end surface by the shape design of the first prism and the third prism.

10. An optical engine for realizing Micro-LED color projection according to claim 9, wherein the projection imaging lens is composed of a conventional lens set or a lens set combining a polarization element and a super surface.