CN115576101A - Optical equipment for eliminating ghost image diffraction - Google Patents

Abstract

The invention discloses an optical device for eliminating ghost image diffraction, which comprises a micro-optical machine, wherein a polarizing device is arranged in the micro-optical machine, and an optical waveguide mechanism is positioned on the light emergent side of the micro-optical machine. The first polarization direction light emitted by the micro-optical machine is sequentially divided into a light ray, a light ray and a light ray by utilizing the zero-order diffraction order, the first diffraction order and the first diffraction order secondary diffraction of the incident coupler, the light ray b is diffracted into the waveguide plate to be transmitted in a total reflection manner and coupled out to the eye socket, the light ray a and the light ray c penetrate through the waveguide plate, the light ray a and the light ray c in the first polarization direction light are converted into a second polarization direction by arranging the reflective quarter-wave plate, the polarization direction of the light ray a and the polarization direction of the light ray c in the second polarization direction are orthogonal to the polarization direction of the polarization device, the light ray a and the light ray c in the second polarization direction are absorbed when passing through the polarization device, and then the light ray a is prevented from entering the optical waveguide mechanism again and being coupled out, so that ghost images are eliminated, and the imaging quality of images in the eye socket can be effectively improved.

Description

A diffractive optical device for eliminating ghost images

technical field

The invention belongs to the field of optics, and in particular relates to a diffraction optical device for eliminating ghost images.

Background technique

AR (augmented reality), MR (mixed reality), and HMD (head-mounted display) are wearable transparent or translucent optical devices that can be used in many fields such as game entertainment, consumption, education, and medical treatment. The optical device at least includes a micro-optical machine, an incident coupler, a waveguide plate and an output coupler, wherein, as shown in Figure 1, the micro-optical machine generally includes a light source, a polarization beam splitter, a micro display screen and an imaging lens, wherein the light source emits The ray passes through a prism (the prism is a polarizing beam splitter, which transmits light in the P polarization direction and reflects light in the S polarization direction) and is reflected to the microdisplay in the S polarization state. A high-quality image with a certain size is then coupled into the waveguide plate with the first diffraction order through the incident coupler for total reflection transmission, and finally the image is copied and coupled out to the orbit through the output coupler, so that the orbit can be The expected image is received.

However, when the output light of the micro-optical machine in the prior art passes through the incident coupler, as shown in Figure 2, its first diffraction order (solid line) will interact with the incident coupler again after being reflected by the waveguide plate, and the The second diffraction of the first diffraction order (dotted line), the generated light will be coupled out from the incident coupler and enter the micro-display, after being reflected by the micro-display, its polarization state will be converted from P to S, and then coupled with the incident again After entering into the waveguide plate, it is transmitted by total reflection, copied by the output coupler and finally coupled out to the eye socket, forming the first ghost image and affecting the imaging quality of the desired image;

In addition, as shown in Figure 3, when the output light of the micro-optical machine passes through the incident coupler, since the incident coupler generally uses a diffractive optical element, such as a surface relief grating (SRG) or a holographic grating, it cannot achieve the first The efficiency of the diffraction order reaches 100%. Therefore, in addition to producing the desired first diffraction order, there is also a highly efficient zero-order non-diffraction light, which will not change direction after passing through the incident coupler, and passes through the waveguide After plate reflection (specular reflection), it will pass through the incident coupler again and reach the microdisplay (dotted line). After being reflected by the microdisplay, the deflection conversion occurs, from P polarization state to S polarization state, and is diffracted again by the incident coupler. The generated first diffraction order (dotted line) is transmitted by total reflection of the waveguide plate, and then copied by the output coupler and coupled out to the human eye to form the second ghost image, the first ghost image, the second ghost image, and the desired Image stacking reduces image quality in the orbit.

Contents of the invention

The object of the present invention is to propose a diffractive optical device for eliminating ghost images in order to solve the problems raised in the background technology.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A diffraction optical device for eliminating ghost images proposed by the present invention includes a micro-optical machine with a built-in polarization device and an optical waveguide mechanism located on the light output side of the micro-optic machine, wherein:

The optical waveguide mechanism includes an incident coupler, a waveguide plate, a reflective quarter-wave plate and an output coupler. The incident coupler, reflective quarter-wave plate and output coupler are all attached to the waveguide plate, and the incident The coupler and the reflective quarter-wave plate are arranged oppositely, the incident coupler and the output coupler are located on the same side of the waveguide plate, and the output coupler is used for incident the light transmitted by the waveguide plate to the orbit.

The polarizing device is located on the side of the incident coupler away from the waveguide plate, and is used to pass the light of the first polarization direction emitted by the micro-optical machine to the incident coupler. The incident coupler uses the zero-order diffraction order, the first diffraction order and Secondary diffraction of the first diffraction order divides light in the first polarization direction into a ray, b ray, and c ray in turn, and the polarization directions of a ray, b ray, and c ray are consistent with the first polarization direction, and the incident coupler utilizes the first polarization direction The first diffraction order diffracts light b into the waveguide plate for total reflection and transmission, and is coupled out to the human eye by the output coupler. The first incident coupler uses the zero-order diffraction order and the first diffraction order to diffract the a The ray and c ray pass through the waveguide plate to reach the reflective quarter-wave plate, and the reflective quarter-wave plate converts the first polarization direction of the a ray and c ray into the second polarization direction and reflects it to the polarizing device, and the second The second polarization direction is orthogonal to the first polarization direction, so that the a-ray and c-ray in the second polarization direction are absorbed by the polarizing device, preventing the a-ray and c-ray from re-entering the optical waveguide mechanism and being coupled out to human eyes, thereby eliminating ghost images.

Preferably, the micro-optical machine also includes a light-emitting light source, a lighting assembly, a micro-display, a prism and an imaging lens, the imaging lens, prism and the micro-display are distributed in sequence, and the imaging lens is arranged close to the optical waveguide mechanism, and the polarizing device is located at the incident Between any two of the coupler, the imaging lens and the prism, the light source is located on one side of the prism, and the optical axis is perpendicular to the optical axis of the micro-display, and the lighting assembly is located between the light source and the prism.

Preferably, the lighting assembly includes a collimating optical element, a uniform optical element and a relay optical element arranged side by side in sequence from the light source to the prism.

Preferably, the micro display screen is an LCOS display screen, the prism is a polarization beam splitter prism, the polarizing device is located between the prism and the imaging lens, and the polarizing device is an analyzer.

Preferably, the micro display screen is a DLP display screen, the prism is composed of two right-angle triangular prisms, and the slopes of the two right-angle triangular prisms are attached, and the polarizing device is located between the incident coupler and the imaging lens or between the imaging lens and the prism Between, the polarizing device is a polarizer.

Preferably, the micro-display is a Micro-LEDs or Micro-OLEDs display, the prisms are X prisms, and the X prisms are composed of four triangular prisms, and each contacted two triangular prisms are plated with light transmission or The reflective film layer, the polarizing device is located between the incident coupler and the imaging lens or between the imaging lens and the prism, and the polarizing device is an analyzer or a polarizer.

Preferably, the included angle between the fast axis of the reflective quarter-wave plate and the first polarization direction is 45°.

Preferably, the reflective quarter-wave plate is an achromatic reflective quarter-wave plate.

Preferably, the light source is an LEDs light source, Micro-LEDs light source, laser light source or OLEDs light source.

Compared with prior art, the beneficial effect of the present invention is:

This optical device uses the zero-order diffraction order, the first diffraction order and the second diffraction of the first diffraction order of the incident coupler to divide the first polarization direction light emitted by the micro-optical machine into a ray, b ray and c ray in sequence , and light b is diffracted into the waveguide plate for total reflection transmission and coupled out to the eye socket, light a and light c pass through the waveguide plate, and set a reflective quarter-wave plate, so that a in the light of the first polarization direction The light and c light are converted to the second polarization direction, and the light in the second polarization direction is perpendicular to the polarization direction of the polarizing device, so that the a and c light rays in the second polarization direction are absorbed when passing through the polarizing device, thereby preventing re-entry into the The optical waveguide mechanism is coupled out to eliminate ghost images, thereby effectively improving the imaging quality of images in the orbit.

Description of drawings

Fig. 1 is the first schematic diagram of the optical device structure in the prior art;

Fig. 2 is the second schematic diagram of the optical device structure in the prior art;

FIG. 3 is a third schematic diagram of the optical device structure in the prior art;

Fig. 4 is a structural schematic diagram of the ghost image elimination diffraction optical device of the present invention;

Fig. 5 is a kind of situation of the polarization state conversion of reflective quarter-wave plate among the present invention;

Fig. 6 is another situation of the polarization state conversion of reflective quarter-wave plate among the present invention;

Fig. 7 is a schematic diagram of an X prism in the present invention.

Explanation of reference numerals: 1. micro-optical machine; 11. luminescent light source; 12. micro display screen; 13. prism; 14. imaging lens; 15. lighting assembly; 2. optical waveguide mechanism; 21. incident coupler; 22. waveguide plate; 23, reflective quarter-wave plate; 24, output coupler; 3, eye socket; 4, polarizing device.

detailed description

The following will clearly and completely describe the technical solutions in the embodiments of the application with reference to the drawings in the embodiments of the application. Apparently, the described embodiments are only some, not all, embodiments of the application. Based on the embodiments in this application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of this application.

It should be noted that when a component is said to be "connected" to another component, it may be directly connected to the other component or intervening components may also exist. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used herein in the description of the application are only for the purpose of describing specific embodiments, and are not intended to limit the application.

As shown in Figure 4-7, a diffraction optical device for eliminating ghost images includes a micro-optical machine 1, a polarizer 4 built in the micro-optical machine 1, and an optical waveguide mechanism 2 located on the light output side of the micro-optical machine 1, wherein:

The optical waveguide mechanism 2 includes an incident coupler 21, a waveguide plate 22, a reflective quarter-wave plate 23 and an output coupler 24, and the incident coupler 21, the reflective quarter-wave plate 23 and the output coupler 24 are all The waveguide plate 22 is attached, and the incident coupler 21 and the reflective quarter-wave plate 23 are arranged oppositely. The incident coupler 21 and the output coupler 24 are located on the same side of the waveguide plate 22. The output coupler 24 is used to connect the waveguide The light transmitted by the plate 22 is incident on the orbit 3 .

The polarizing device 4 is located on the side of the incident coupler 21 away from the waveguide plate 22, and is used to pass the light of the first polarization direction emitted by the micro-optical machine 1 to the incident coupler 21. The incident coupler 21 utilizes the zero-order diffraction order, The first diffraction order and the second diffraction of the first diffraction order divide the light in the first polarization direction into a ray, b ray and c ray in turn, and the polarization directions of a ray, b ray and c ray are consistent with the first polarization direction , the incident coupler 21 uses the first diffraction order to diffract light b into the waveguide plate 22 for total reflection transmission, and is coupled out to the orbit 3 by the output coupler 24, the first incident coupler 21 uses the zero-order diffraction order and the second Secondary diffraction of the first order of diffraction passes light a and light c through waveguide plate 22 to reflective quarter-wave plate 23, and reflective quarter-wave plate 23 converts the first polarization direction of light a and light c to Converted to the second polarization direction and reflected to the polarization device 4, and the second polarization direction is orthogonal to the first polarization direction, so that the a-ray and c-ray of the second polarization direction are absorbed by the polarization device 4, preventing the a-ray and c-ray from re-entering The optical waveguide mechanism 2 is coupled out to the eye socket 3, thereby eliminating ghost images.

Specifically, taking FIG. 4 as an example, the incident coupler 21 is glued on the lower surface of the waveguide plate 22, the reflective quarter-wave plate 23 is glued on the upper surface of the waveguide plate 22, and the incident coupler 21 and the reflective quarter-wave plate One wave plate 23 is located at the left end of the micro-optic machine 1, the output coupler 24 is glued on the lower surface of the waveguide plate 22, and is close to the right end of the waveguide plate 22, the micro-optic machine 1 is located under the incident coupler 21, and the polarizer 4 is located at Below the input coupler 21 (one of the cases shown in FIG. 4 ), the orbit 3 is located below the output coupler 24 . The above orientations are for convenience of description only and are not specifically limited. The first polarization direction light can be P polarization direction light, also can be S polarization direction light, if the first polarization direction light is P polarization direction light, then the second polarization direction is S polarization direction; if the first polarization direction light is S polarization direction If the polarization direction is light, the second polarization direction is the P polarization direction. The dotted arrow in FIG. 4 indicates the second polarization direction.

In one embodiment, the micro-optical machine 1 also includes a light source 11, a lighting assembly 15, a micro-display 12, a prism 13 and an imaging lens 14, the imaging lens 14, the prism 13 and the micro-display 12 are distributed in sequence, and the imaging lens 14 Set close to the optical waveguide mechanism 2, the polarizing device 4 is located between any two of the incident coupler 21, the imaging lens 14 and the prism 13, the light source 11 is located on one side of the prism 13, and the optical axis is in line with the micro The optical axis of the display screen 12 is vertical, and the lighting assembly 15 is located between the light source 11 and the prism 13 .

Specifically, the light source 11 , the lighting assembly 15 and the prism 13 are sequentially arranged from left to right, the microdisplay 12 is located below the prism 13 , and the imaging lens 14 is located above the prism 13 and below the incident coupler 21 . The imaging lens 14 includes a plurality of lenses, and each lens may be a plane mirror, an aspheric lens or a spherical lens. According to different types of micro-display screens 12, the positions of the polarizers 4 are different.

In one embodiment, the lighting assembly 15 includes collimating optical elements, uniform light optical elements and relay optical elements distributed in sequence from the light source 11 to the prism 13 .

Specifically, the collimating optical element, homogenizing optical element and relay optical element are arranged sequentially from left to right. The collimating optical element is used to collimate the light, which can be composed of a single or multiple spherical lenses, or can be a single or a plurality of aspheric lenses, the homogenizing optical element is used to homogenize the light, which can be a microlens array or a diffuser, and the relay optical element is used to modulate the light, which can be composed of a plurality of spherical lenses or a plurality of composed of aspheric lenses.

In one embodiment, the micro display screen 12 is an LCOS display screen, the prism 13 is a polarizing beam splitter, the polarizing device 4 is located between the prism 13 and the imaging lens 14, and the polarizing device 4 is an analyzer.

Specifically, the polarization beam splitter prism is generally made of two right-angle prisms with hypotenuse glued together or optical glue, and a polarization beam splitter film is coated on the slope. The light in the first polarization direction output by the micro-optical machine 1 can be the light in the P polarization direction or the light in the S polarization direction. Assuming it is the light in the P polarization direction, the analyzer positioned between the prism 13 and the imaging lens 14 uses P polarization direction light. The analyzer in the polarization direction allows the light in the P polarization direction to pass through, and the polarization directions of a ray, b ray, and c ray are also in the P polarization direction, and the incident coupler 21 uses the first diffraction order to diffract the b ray to the waveguide plate 22 It is transmitted by total reflection in the center and is coupled out to the orbit 3 by the output coupler 24. The first incident coupler 21 uses the zero-order diffraction order and the second order diffraction of the first diffraction order to respectively pass the a-ray and c-ray through the waveguide plate 22 Reach the reflective quarter-wave plate 23, the reflective quarter-wave plate 23 converts the P polarization direction of the a light and the c light into the S polarization direction and reflects it to the polarizing device 4, and the S polarization direction is the same as that of the analyzer. The P polarization direction is orthogonal, so that the a-ray and c-ray of the second polarization direction are absorbed by the polarizing device 4, preventing the a-ray and c-ray from re-entering the optical waveguide mechanism 2 and being coupled out to the eye socket 3, thereby eliminating ghost images.

In one embodiment, the micro-display screen 12 is a DLP display screen, the prism 13 is composed of two right-angle triangular prisms, and the slopes of the two right-angle triangular prisms are attached, and the polarizing device 4 is located between the incident coupler 21 and the imaging lens 14 Sometimes or between the imaging lens 14 and the prism 13, the polarizing device 4 is a polarizer.

Specifically, in addition to being composed of two right-angle triangular prisms, the prism 13 may also be a non-right-angle triangular prism, and there is no coating between the two triangular prisms. The polarizing device 4 may be located anywhere between the incident coupler 21 and the imaging lens 14 or between the imaging lens 14 and the prism 13 . Assuming that the light in the first polarization direction output by the micro-optical machine 1 is the light in the S polarization direction, the polarizer is a polarizer in the S polarization direction, so that the light in the S polarization direction passes through, and the polarization directions of a ray, b ray, and c ray It is also the S polarization direction. The incident coupler 21 uses the first diffraction order to diffract b rays into the waveguide plate 22 for total reflection and transmission, and is coupled out to the orbit 3 by the output coupler 24. The first incident coupler 21 uses the zero order Diffraction order and first diffraction order secondary diffraction pass light a and light c through waveguide plate 22 to reflective quarter-wave plate 23 respectively, and reflective quarter-wave plate 23 passes light a and light c The S polarization direction of the P polarization direction is converted to the P polarization direction and reflected to the polarizing device 4, and the P polarization direction is orthogonal to the S polarization direction of the polarizer, so that the a light and the c light of the P polarization direction are absorbed by the polarizing device 4, preventing the a light and the c The light enters the optical waveguide mechanism 2 again and is coupled out to the eye socket 3, thereby eliminating ghost images.

In one embodiment, the micro-display screen 12 is a Micro-LEDs or Micro-OLEDs display screen, the prism 13 is an X prism, and the X prism is composed of four triangular prisms, and each contacted two triangular prisms are plated with A film layer for transmitting or reflecting light of different wavelengths. The polarizing device 4 is located between the incident coupler 21 and the imaging lens 14 or between the imaging lens 14 and the prism 13. The polarizing device 4 is an analyzer or a polarizer.

Specifically, as shown in Figure 7, it is an X prism, where A, B, C, and D represent the film layers coated between the two contacting triangular prisms, for example, the A and C film layers reflect blue light, and transmit green light and red light , B and D film layers reflect red light, transmit green light and blue light, and X prisms achieve the effect of multi-color light synthesis. The polarizing device 4 can be placed separately, or can be glued to the upper surface of the prism 13 or the upper surface of one of the imaging lenses 14 with a plane surface to save space. Assuming that the light in the first polarization direction output by the micro-optical machine 1 is light in the S polarization direction, the polarizer or analyzer is a polarizer or analyzer in the S polarization direction, so that the light in the S polarization direction passes through, and the a ray, The polarization direction of light b and light c is also the S polarization direction. The incident coupler 21 uses the first diffraction order to diffract light b to the waveguide plate 22 for total reflection and transmission, and is coupled out to the orbit 3 by the output coupler 24. An incident coupler 21 uses the zero-order diffraction order and the second-order diffraction of the first diffraction order to pass the a-ray and c-ray respectively through the waveguide plate 22 to the reflective quarter-wave plate 23, and the reflective quarter-wave The sheet 23 converts the S polarization direction of the a light and the c light to the P polarization direction and reflects it to the polarizing device 4, and the P polarization direction is orthogonal to the S polarization direction of the polarizer or the analyzer, so that the a light and the Light c is absorbed by the polarizing device 4 to prevent light a and light c from re-entering the optical waveguide mechanism 2 and being coupled to the eye socket 3, thereby eliminating ghost images.

In one embodiment, the included angle between the fast axis of the reflective quarter-wave plate 23 and the light in the first polarization direction is 45°.

In one embodiment, reflective quarter wave plate 23 is an achromatic reflective quarter wave plate.

Specifically, the achromatic reflective quarter-wave plate is composed of two different birefringent crystal materials, so that in the required visible light band 400nm-700nm, the difference in phase delay can be offset by the above two materials, so that all phase retardation in the wavelength range is a quarter wavelength. As shown in Figures 5 and 6 (P represents the light in the P polarization direction, and S represents the light in the S polarization direction), if the light incident to the reflective quarter-wave plate 23 is the light in the P polarization direction, then the reflected light is in the S polarization direction Light; if the light incident on the reflective quarter-wave plate 23 is light in the S polarization direction, the reflected light is light in the P polarization direction. Meanwhile, the width of the reflective quarter-wave plate 23 along the left-right direction is greater than or equal to the width of the incident coupler 21 along the left-right direction.

In one embodiment, the light-emitting light source 11 is an LEDs light source, Micro-LEDs light source, laser light source or OLEDs light source.

This optical device uses the zero-order diffraction order, the first diffraction order and the second diffraction of the first diffraction order of the incident coupler to divide the first polarization direction light emitted by the micro-optical machine into a ray, b ray and c ray in sequence , and light b is diffracted into the waveguide plate for total reflection transmission and coupled out to the eye socket, light a and light c pass through the waveguide plate, and set a reflective quarter-wave plate, so that a in the light of the first polarization direction The light and c light are converted to the second polarization direction, and the light in the second polarization direction is perpendicular to the polarization direction of the polarizing device, so that the a and c light rays in the second polarization direction are absorbed when passing through the polarizing device, thereby preventing re-entry into the The optical waveguide mechanism is coupled out to eliminate ghost images, thereby effectively improving the imaging quality of images in the orbit.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express the more specific and detailed embodiments described in the present application, but should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of protection of the patent application should be based on the appended claims.

Claims (9)

1. A diffraction optical device for eliminating ghost images, comprising a micro-optical machine (1), characterized in that: said micro-optical machine (1) is built with a polarizer (4), and is located at said micro-optic machine (1) to emit light The optical waveguide mechanism (2) on the side, wherein: The optical waveguide mechanism (2) includes an incident coupler (21), a waveguide plate (22), a reflective quarter-wave plate (23) and an output coupler (24), and the incident coupler (21) , reflective quarter-wave plate (23) and output coupler (24) are all attached to the waveguide plate (22) settings, and the incident coupler (21) and reflective quarter-wave plate ( 23) Relatively arranged, the incident coupler (21) and the output coupler (24) are located on the same side of the waveguide plate (22), and the output coupler (24) is used to use the waveguide plate (22) The transmitted light is incident on the orbit (3); The polarizing device (4), located on the side of the incident coupler (21) away from the waveguide plate (22), is used to pass the light of the first polarization direction emitted by the micro-optical machine (1) through to reach The incident coupler (21), the incident coupler (21) divides the light in the first polarization direction into a ray, b ray, and c ray, and the polarization directions of the a ray, b ray, and c ray are consistent with the first polarization direction, and the incident coupler (21) diffracts the b ray to Total reflection transmission in the waveguide plate (22), and coupled out to the orbit (3) by the output coupler (24), the first incident coupler (21) utilizes the zero-order diffraction order and the first diffraction Order secondary diffraction passes a ray and c ray respectively through the waveguide plate (22) to the reflective quarter-wave plate (23), and the reflective quarter-wave plate (23) will The first polarization direction of light a and light c is converted into a second polarization direction and reflected to the polarizer (4), and the second polarization direction is orthogonal to the first polarization direction, so that a of the second polarization direction The ray and c ray are absorbed by the polarizing device (4), preventing the a ray and c ray from reentering the optical waveguide mechanism (2) and being coupled to the eye socket (3), thereby eliminating ghost images. 2. The diffraction optical device for eliminating ghost images according to claim 1, characterized in that: the micro-optical machine (1) also includes a light source (11), an illumination assembly (15), a micro-display screen (12), a prism (13) and imaging lens (14), described imaging lens (14), prism (13) and microdisplay screen (12) are distributed sequentially, and described imaging lens (14) is arranged near described optical waveguide mechanism (2) , the polarizing device (4) is located between any two of the incident coupler (21), imaging lens (14) and prism (13), and the light emitting source (11) is located in the prism (13) and the optical axis is perpendicular to the optical axis of the micro display screen (12), and the lighting assembly (15) is located between the light emitting light source (11) and the prism (13). 3. The diffraction optical device for eliminating ghost images according to claim 2, characterized in that: the illumination assembly (15) includes collimating optical elements arranged side by side in sequence from the light source (11) to the prism (13) , Uniform optical components and relay optical components. 4. eliminating ghost image diffractive optical equipment as claimed in claim 2, is characterized in that: described micro-display screen (12) is LCOS display screen, and described prism (13) is polarization beam splitter prism, and described polarizer (4 ) is located between the prism (13) and the imaging lens (14), and the polarizing device (4) is an analyzer. 5. Eliminate ghost image diffraction optical equipment as claimed in claim 2, it is characterized in that: described micro-display screen (12) is DLP display screen, and described prism (13) is made up of two right-angle triangular prisms, and two The oblique planes of the right-angle triangular prism fit together, and the polarizing device (4) is positioned between the incident coupler (21) and the imaging lens (14) or between the imaging lens (14) and the prism (13), and the polarizing device (4) is a polarizer. 6. The diffraction optical device for eliminating ghost images as claimed in claim 2, characterized in that: the micro-display screen (12) is a Micro-LEDs or Micro-OLEDs display screen, and the prism (13) is an X prism, so Described X prism is made up of four triangular prisms, and between two triangular prisms of every contact is coated with the film layer that realizes the light transmission or reflection of different wavelengths, and described polarization device (4) is positioned at incident coupler (21) and imaging Between the lenses (14) or between the imaging lens (14) and the prism (13), the polarizing device (4) is an analyzer or a polarizer. 7. The diffraction optical device for eliminating ghost images according to claim 1, characterized in that: the included angle between the fast axis of the reflective quarter-wave plate (23) and the first polarization direction is 45°. 8. The diffraction optical device for eliminating ghost images according to claim 1, characterized in that: the reflective quarter-wave plate (23) is an achromatic reflective quarter-wave plate. 9. The diffractive optical device for eliminating ghost images according to claim 2, characterized in that: the light-emitting light source (11) is an LEDs light source, a Micro-LEDs light source, a laser light source or an OLEDs light source.

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