CN118112810A - Display assembly and AR equipment - Google Patents

Abstract

The application discloses a display component and AR equipment, which relate to the technical field of optical display, and the display component comprises a light machine, a dispersion element arranged on the light emitting side of the light machine and an optical waveguide arranged on the light emitting side of the dispersion element, wherein the light emitting side of the optical waveguide is provided with the dispersion compensation element, the light machine emits mixed light beams, the dispersion element deflects the light beams with different wavelengths in the mixed light beams to different degrees, so that the light beams with different wavelengths are incident into the coupling-in area of the optical waveguide at different angles and are coupled out to the dispersion compensation element by the coupling-out area of the optical waveguide, and the dispersion compensation element deflects the light beams with different wavelengths in the opposite direction to the deflection direction of the dispersion element and emits the light beams to form the emergent light beams of the display component. The display component and the AR equipment provided by the application can improve the uniformity of light emitted by the display component.

Description

Display assembly and AR equipment

Technical Field

The application relates to the technical field of optical display, in particular to a display component and AR equipment.

Background

Augmented reality (Augmented Reality, AR) technology is a technology that smartly merges virtual information with the real world, and such a head-mounted display using the augmented reality technology allows people to view the surrounding environment while projecting virtual images to the eyes of the people. Among them, the diffractive optical waveguide is a display scheme of the mainstream AR device, and many AR devices adopt such a display scheme, and since the diffractive optical waveguide has the advantages of light weight, large viewing angle, large eye movement range, and low mass production cost, it is generally considered as a mainstream display technical route in the AR industry.

If the light beam emitted by the optical machine is to be guided into human eyes by the diffraction optical waveguide, the light beam emitted by the optical machine needs to be coupled into the optical waveguide through the coupling-in area through the coupling-out process, and is emitted into the human eyes through the coupling-out area after being transmitted by total reflection for multiple times. Specifically, as shown in fig. 1, the coupling-in area and the coupling-out area of the diffractive optical waveguide are provided with diffraction elements, and the diffraction elements realize coupling-in and coupling-out of the light beam by utilizing the diffraction effect of the light. When the optical machine emits the color light beam, the diffraction angles of the light beams with different wavelengths are different due to the light splitting phenomenon of the diffraction element, so that the step sizes of the light beams with different colors for completing twice total reflection at the same interface are different, the times of the light beams with different wavelengths for generating total reflection in the optical waveguide are different, the times of the light beams with different wavelengths for contacting the diffraction element in the coupling-out area are different, and the uniformity of the light beams output by the diffraction optical waveguide is poor.

Disclosure of Invention

The application aims to provide a display component and AR equipment, which can improve the uniformity of light emitted by the display component.

In one aspect, an embodiment of the present application provides a display assembly, including an optical engine, a dispersive element disposed on an optical-engine light-emitting side, and an optical waveguide disposed on the optical-dispersion element light-emitting side, where the optical-engine light-emitting side is provided with a dispersion compensation element, the optical engine emits a mixed light beam, the dispersive element deflects light beams of different wavelengths in the mixed light beam to different extents, so that light beams of different wavelengths in the same field of view enter an optical waveguide coupling-in area at different angles, and are coupled to the dispersion compensation element by an optical waveguide coupling-out area, and the dispersion compensation element deflects light beams of different wavelengths in a direction opposite to the direction of the deflection of the dispersive element and emits an outgoing light beam forming the display assembly.

As an embodiment, the dispersive element comprises a transmissive diffraction grating arranged between the light machine and the light guide coupling-in region, the transmissive diffraction grating deflecting the blue light, the green light and the red light of the mixed light beam to different extents to reduce diffraction angle differences formed between the red light, the green light and the blue light in the light guide coupling-in region.

As an implementation manner, the zero-field mixed beam emitted by the optical machine has a preset included angle with the normal direction of the transmission type diffraction grating so as to make the green light vertically enter the coupling-in area.

As an implementation manner, the dispersive element includes a blazed grating, the optical machine and the optical waveguide are disposed on the same side of the blazed grating, and the blazed grating reflects the mixed light beam and deflects blue light, green light and red light in the mixed light beam to different degrees so as to reduce diffraction angle differences formed between the red light, the green light and the blue light in the coupling-in area of the optical waveguide.

As an implementation manner, the zero-field mixed beam emitted by the optical machine is perpendicular to the grating plane of the blazed grating method so that green light is perpendicularly incident into the coupling-in area.

As an embodiment, the dispersion compensating element is a transmissive diffraction element, the period of the transmissive diffraction element is the same as that of the transmissive diffraction grating, and the diffraction orders are opposite; the blazed grating has the same period as the transmission diffraction element and has opposite diffraction orders.

As an embodiment, the dispersion compensation element and the light-emitting side of the transmission diffraction grating are bonded to each other with an angle selective transmission film so as to prevent transmission of the zero-order diffracted light beam.

As an implementation manner, the dispersion element includes a first dispersion prism, the first dispersion prism is disposed between the optical machine and the optical waveguide coupling region, the first dispersion prism deflects the blue light, the green light and the red light in the mixed light beam to different degrees so as to reduce diffraction angle differences formed between the red light, the green light and the blue light in the optical waveguide coupling region, and the dispersion compensation element includes a second dispersion prism, and the deflection directions of the first dispersion prism and the second dispersion prism to the light beam are opposite.

As an implementation manner, the zero-field mixed beam emitted by the optical machine has a preset included angle with the incident surface of the dispersion prism so as to make the green light vertically enter the coupling-in area.

Another aspect of an embodiment of the present application provides an AR device including the display assembly described above.

The beneficial effects of the embodiment of the application include:

The application provides a display component, which comprises a light machine, a dispersion element arranged on the light emitting side of the light machine and an optical waveguide arranged on the light emitting side of the dispersion element, wherein the light emitting side of the optical waveguide is provided with a dispersion compensation element, the light machine emits mixed light beams, the dispersion element deflects the light beams with different wavelengths in the mixed light beams to different degrees, so that the light beams with different wavelengths in the same view field are incident into a coupling-in area of the optical waveguide at different angles, the diffraction angle difference formed by the light beams with different wavelengths in the coupling-in area is reduced, and compared with the prior art, the diffraction angle difference of the light beams with different wavelengths in the same view field diffracted by the coupling-in area is reduced, the diffraction order difference of the light with different wavelengths in the exit pupil area is reduced, and the uniformity of the optical waveguide display is improved. Each light beam is subjected to multiple total reflections in the optical waveguide and is coupled out to the dispersion compensation element by the coupling-out region of the optical waveguide, and the dispersion compensation element deflects the light beams with different wavelengths in the opposite direction to the deflection direction of the dispersion element and emits the light beams to form an emergent light beam of the display assembly, so that the light with different wavelengths in the same view field enters the eyes of a viewer at the same angle. Therefore, the display component provided by the application can improve the uniformity of light emitted by the display component.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a prior art display assembly;

FIG. 2 is a schematic diagram of a display device according to an embodiment of the present application;

FIG. 3 is a schematic diagram of a dispersive element according to an embodiment of the present application;

FIG. 4 is a second schematic diagram of a display device according to an embodiment of the present application;

FIG. 5 is a third schematic diagram of a display device according to an embodiment of the present application;

FIG. 6 is a second schematic diagram of a dispersive element according to an embodiment of the present application;

FIG. 7 is a schematic diagram of a display device according to an embodiment of the present application;

FIG. 8 is a schematic diagram of a display device according to an embodiment of the present application;

FIG. 9 is a third schematic diagram of a dispersive element according to an embodiment of the present application;

FIG. 10 is a schematic diagram of a display device according to an embodiment of the present application;

Fig. 11 is a schematic diagram of a dispersion element and a dispersion compensation element according to an embodiment of the present application.

Icon: 100-a display assembly; 110-ray machine; a 120-dispersion element; 121-a transmissive diffraction grating; 122-blazed gratings; 123-a first dispersion prism; 130-an optical waveguide; 131-a coupling-in region; 132-a coupling-out region; a 140-dispersion compensating element; 141-a transmissive diffraction element; 142-a second dispersion prism; 151-angle selective permeable membrane; 152-antireflection film.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.

It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.

In the description of the present application, it should be noted that, directions or positional relationships indicated by terms such as "center", "vertical", "horizontal", "inner", "outer", etc., are directions or positional relationships based on those shown in the drawings, or those that are conventionally put in place when the product of this application is used, are merely for convenience of describing the present application and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be construed as limiting the present application. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.

The display assembly in the prior art, as shown in fig. 1, includes a light machine and an optical waveguide disposed at a light emitting side of the light machine, wherein a coupling-in area of the optical waveguide is provided with a coupling-in grating, and a coupling-out area of the optical waveguide is provided with a coupling-out grating. The light machine comprises a micro display screen and a collimation element arranged on the light emitting side of the micro display screen, the micro display screen is regarded as a plurality of point light sources, each point light source corresponds to one pixel, spherical light beams emitted by the point light sources become plane light beams after passing through a collimation lens system, the emergent angles of the light beams of different pixel points are different, and each emergent angle corresponds to one field of view. The light emitted from each pixel point is usually mixed light containing components with different wavelengths, and the mixed light is formed by mixing three kinds of light with different wavelengths of red (r), green (g) and blue (b) according to different proportions. The coupling-in grating on the optical waveguide couples the light beam emitted by the optical engine into the optical waveguide, and due to the diffraction effect of the coupling-in grating, the diffraction angles of the light beams with the same field of view and different wavelengths in the mixed light entering the optical waveguide are different, as shown in fig. 1, the diffraction angle (theta _r) of red light (r) is maximum, the diffraction angle (theta _g) of green light (g) is twice, and the diffraction angle (theta _b) of blue light (b) is minimum.

The number of times of total reflection of light with different diffraction angles (namely, light with different wavelengths) in the optical waveguide is different, the number of times of total reflection of light with larger diffraction angle in the optical waveguide is smaller, namely, the step interval of two continuous total reflection at the same interface is larger; the smaller the diffraction angle, the more times total reflection occurs within the optical waveguide, i.e. the smaller the step size interval between successive total reflections at the same interface.

Since the number of total reflections of light at different diffraction angles in the optical waveguide is different, the number of times the light contacts the outcoupling grating in the outcoupling region is also different, which results in that the uniformity of the output distribution of light at different wavelengths in the outcoupling region is different; the red light has fewer diffraction orders than the green light in the coupling-out region and the blue light has more diffraction orders than the green light in the coupling-out region, and when the coupling-out grating structure is arranged such that the green light coupling-out distribution is uniform, the blue light is brighter near the coupling-in region and darker far from the coupling-in region, and the red light is darker near the coupling-in region and brighter far from the coupling-in region. Causing color deviations in the display of the out-coupling area.

The application provides a display assembly 100, as shown in fig. 2, 5 and 8, comprising a light machine 110, a dispersion element 120 arranged on the light emitting side of the light machine 110 and an optical waveguide 130 arranged on the light emitting side of the dispersion element 120, wherein the light emitting side of the optical waveguide 130 is provided with a dispersion compensation element 140, the light machine 110 emits mixed light beams, the dispersion element 120 deflects light beams with different wavelengths in the mixed light beams to different degrees, so that the light beams with different wavelengths enter a coupling-in area 131 at different angles and are coupled to the dispersion compensation element 140 by a coupling-out area 132 of the optical waveguide 130, and the dispersion compensation element 140 deflects the light beams with different wavelengths in the opposite direction to the deflection direction of the dispersion element 120 and emits the emitted light beams forming the display assembly 100.

In the display assembly 100 provided in the embodiment of the present application, the dispersive element 120 is disposed on the light emitting side of the light machine 110, the mixed light emitted from the light machine 110 enters the dispersive element 120, the dispersive element 120 deflects the light beams with different wavelengths in the mixed light to different degrees, so that the light beams with different wavelengths in the same field of view are separated, and the light beams with different wavelengths exit the dispersive element 120 at different angles, for example, after being dispersed by the dispersive element 120, three light beams of red (r), green (g) and blue (b) are formed, and the three light beams of red, green and blue enter the coupling region 131 at different angles, and enter the optical waveguide 130 through the coupling grating diffraction of the coupling region 131. At the coupling grating of the coupling region 131 of the optical waveguide 130, the light emitted from the dispersive element 120 enters the optical waveguide 130 through the diffraction of the coupling grating, and since the incident angles of the three light beams entering the coupling region 131 are different, compared with the prior art, the angle difference of the diffraction angles of the three light beams is reduced after the diffraction of the coupling grating, thereby reducing the diffraction order difference of the light beams with different wavelengths in the exit pupil region and improving the uniformity of the display of the optical waveguide 130. Because the dispersion effect of the dispersion element 120 causes the coupling-out angles of the light beams with different wavelengths to be different after the light beams with the same pixel are coupled out in the exit pupil area, the dispersion compensation element 140 is arranged on the light-emitting side of the optical waveguide 130 to further deflect the coupling-out light with the same pixel towards the opposite deflection direction, so that the light beams with different wavelengths with the same pixel enter the eyes of the viewer at the same angle.

According to the display assembly 100 provided by the application, the dispersive element 120 and the dispersion compensating element 140 are respectively arranged on the light incident side and the light emergent side of the optical waveguide 130, and the dispersive element 120 deflects the light beams with different wavelengths in the mixed light beam to different extents, so that the light beams with different wavelengths are incident into the coupling-in area 131 at different angles, and further, the diffraction angle difference formed by the light beams with different wavelengths in the coupling-in area 131 is reduced, compared with the prior art, the difference of the diffraction angles of the light beams diffracted by the coupling-in area 131 is reduced, and therefore, the diffraction order difference of the light with different wavelengths in the exit pupil area is reduced, and the uniformity of the display of the optical waveguide 130 is improved. Each light beam undergoes multiple total reflections in light guide 130 and is coupled out by coupling-out region 132 of light guide 130 to dispersion compensating element 140, where dispersion compensating element 140 deflects the light beams of different wavelengths in a direction opposite to that of dispersion element 120 and outputs an output light beam forming display assembly 100 such that light of different wavelengths in the same field of view enters the viewer's eye at the same angle. Therefore, the display assembly 100 provided by the application can improve the uniformity of light emitted by the display assembly 100.

Example 1

Alternatively, as shown in fig. 2,3 and 4, the dispersive element 120 comprises a transmissive diffraction grating 121, the transmissive diffraction grating 121 being disposed between the light engine and the light guide 130 in-coupling region 131, the transmissive diffraction grating 121 deflecting the blue, green and red light in the mixed light beam to different extents so that the red, green and blue light are incident on the light guide 130 at different angles.

As shown in fig. 3 and fig. 4, when the dispersive element 120 adopts the transmissive diffraction grating 121, the optical bench 110 is disposed on one side of the transmissive diffraction grating 121 away from the optical waveguide 130, that is, the transmissive diffraction grating 121 is located between the optical bench 110 and the coupling-in region 131, the mixed light beam emitted from the optical bench 110 enters the transmissive diffraction grating 121, and the transmissive diffraction grating 121 deflects the blue light, the green light and the red light in the mixed light beam to different extents, so that the red light, the green light and the blue light enter the optical waveguide 130 at different angles, and the deflection of the transmissive diffraction grating 121 can reduce the diffraction angle difference formed between the light beams with different wavelengths in the coupling-in region 131 of the optical waveguide, thereby improving the uniformity of the display assembly 100.

In one implementation manner of the embodiment of the present application, the zero-field mixed beam emitted from the optical bench 110 has a preset included angle with the normal direction of the transmissive diffraction grating 121, so that the zero-field green light is perpendicularly incident to the plane where the coupling-in region 131 is located.

Alternatively, the dispersion compensating element 140 is a transmissive diffraction element 141, the period of the transmissive diffraction element 141 is the same as that of the transmissive diffraction grating 121, and the diffraction orders are opposite.

When the dispersion compensating element 140 is a transmissive diffraction element 141, since the diffraction orders of the diffraction element include the zero order, ±1 order … …, in which the direction of the zero order diffracted light is unchanged, the direction of the deflection of +1 and-1 orders is opposite, in order to make the direction of the deflection of the light beam by the transmissive diffraction element 141 and the transmissive diffraction grating 121 opposite. In the embodiment of the application, the period of the transmission type diffraction element 141 is the same as that of the transmission type diffraction grating 121, and the diffraction orders are opposite, namely when the transmission type diffraction grating 121 passes through +1 order diffraction light, the transmission type diffraction element 141 passes through-1 order diffraction light; when the transmission diffraction grating 121 passes-1 order diffracted light, the transmission diffraction element 141 passes +1 order diffracted light.

Alternatively, the transmissive diffraction grating 121 and the transmissive diffraction element 141 are provided with an angle selective transmission film 151 on their light exit side so as to prevent a small amount of zero-order diffracted light beams from transmitting.

In addition, since the light beam energy is mainly concentrated in +1 order or-1 order diffraction order when the transmissive diffraction grating 121 and the transmissive diffraction element 141 diffract, the angle selective transmission film 151 can prevent the light beam of other diffraction orders from entering the optical waveguide 130 or human eyes in order to reduce stray light formed by the light of other diffraction orders, thereby affecting the display effect.

As shown in fig. 3, the grating period d1 of the transmissive diffraction grating 121 is 800nm, and when the zero-field mixed beam emitted from the optical machine 110 enters the transmissive diffraction grating 121 at the angle β, the diffraction angle of green light (g) is parallel to the normal line of the grating surface, according to the grating equation (1)As can be seen from the calculation, β=43.04 °, red light diffraction angle θ _r1 =5.67 °, blue light diffraction angle θ _b1 =6.17°, where n ₁ is the exit medium refractive index, n ₂ is the incident medium refractive index, θ is the diffraction angle, α is the incident angle, k is the diffraction order, λ is the wavelength of light, and d is the diffraction grating period. When the red light and the blue light are respectively incident on the coupling-in region 131 at θ _r1、θ_b1, as shown in fig. 4, it is known from the equation of the grating that θ _r、θ_g、θ_b is 54.46 °, 49.13 °, and 43.92 °. Assuming that the thickness of the substrate of optical waveguide 130 is h=2mm, +1-order diffracted light is totally reflected twice in succession on the same side within the substrate of optical waveguide 130, step l is calculated by formula (2): l=2 htan θ. From the calculation of the formula (2), l _r1、l_g1、l_b1 was found to be 5.60mm, 4.62mm, and 3.85mm, respectively. The step interval difference between red light and green light is l _r1-l_g1 =0.98 mm, the step interval difference between red light and blue light is l _r1-l_b1 =1.75 mm, and the step interval difference between green light and blue light is l _g1-l_b1 =0.77 mm. Wherein the refractive index n ₁ of optical waveguide 130 is 1.9, the grating period d is 380nm, the red light wavelength lambda _(r) is 625nm, the green light wavelength lambda _(g) is 546nm, and the blue light wavelength lambda _(g) is 460nm.

Example two

Unlike the implementation of the first embodiment, the dispersive element 120 of the second embodiment adopts the blazed grating 122, and since the blazed grating 122 is a reflective grating, the optical engine 110 and the optical waveguide 130 are disposed on the same side of the blazed grating 122, and the mixed light beam emitted from the optical engine 110 is reflected by the blazed grating 122 and deflects the blue light, the green light and the red light in the mixed light beam to different degrees during the reflection process.

As shown in fig. 6, when the grating period d1 of the blazed grating 122 is set to 800nm, m is the normal line of the plane of the blazed grating 122, and the zero-field mixed beam emitted from the optical machine 110 is incident on the blazed grating in the direction parallel to the normal line of the plane of the blazed grating 122, the blazed angle a of the grating is set such that the green light is perpendicularly incident on the coupling-in region 131, and the red light and the blue light are respectively incident on the coupling-in region 131 at θ _r1、θ_b1. As shown in fig. 7, θ _r、θ_g、θ_b was found to be 54.46 °, 49.13 °, and 43.92 ° by calculation of formula (1), and l _r1、l_g1、l_b1 was found to be 5.60mm, 4.62mm, and 3.85mm by calculation of formula (2). The step interval difference between red light and green light is l _r1-l_g1 =0.98 mm, the step interval difference between red light and blue light is l _r1-l_b1 =1.75 mm, and the step interval difference between green light and blue light is l _g1-l_b1 =0.77 mm.

In order to more clearly show the beneficial effects of the embodiments of the present application, the summary of the data of the prior art, embodiment one, embodiment two is shown in table one:

Table parameter comparison of various embodiments

	Prior Art	Example 1	Example two
				θr(°)	59.96	54.46°	54.46°
θg(°)	49.13	49.13°	49.13°
				θb(°)	39.58	43.92°	43.92°
lr(mm)	6.92	5.60	5.60
				lg(mm)	4.62	4.62	4.62
lb(mm)	3.31	3.85	3.85
				lr-lg(mm)	2.3	0.98	0.98
lr-lb(mm)	3.61	1.75	1.75
				lg-lb(mm)	1.01	0.77	0.77

As can be seen from the table, the difference between diffraction angles of light of different wavelengths and the step interval difference of total reflection of light of different wavelengths continuously occurring twice on the same side of the optical waveguide 130 are reduced, thereby improving the uniformity of color display of the display assembly 100.

Example III

Unlike the second embodiment, the dispersive element 120 of the third embodiment adopts the first dispersive prism 123, as shown in fig. 8, 9 and 10, the dispersive element 120 is the first dispersive prism 123, the first dispersive prism 123 is disposed between the light engine 110 and the light guide 130 coupling-in area 131, the first dispersive prism 123 deflects the mixed light beam emitted from the light engine 110 to different degrees so that the red light beam, the green light beam and the blue light beam are incident on the light guide 130 at different angles, the dispersion compensating element 140 includes the second dispersive prism 142, and the direction of deflection of the light beam by the first dispersive prism 123 and the second dispersive prism 142 is opposite.

The zero-field mixed beam emitted by the optical machine 110 enters the first dispersion prism 123 at a preset angle beta 2, and the refraction is carried out twice on the upper surface and the lower surface of the first dispersion prism 123, wherein the refractive index of the first dispersion prism 123 is nλ, namely, the first dispersion prism 123 has different refractive indexes for light with different wavelengths, so that the first dispersion prism 123 generates different deflection for the light with different wavelengths, and the longer the wavelength is, the smaller the refractive index is, and the smaller the deflection is; the shorter the wavelength, the larger the refractive index and the larger the deflection.

The relation between the incident angle and refraction angle of the mixed light is calculated by the formula (3): n ₀sinβ＝n_λ sina, wherein n ₀ is the refractive index of the incident medium, β is the incident angle, n _λ is the refractive index of the refractive medium, and α is the refractive angle. As shown in fig. 9 and 10, when the mixed light enters the prism at the angle (β ₁), the green light is perpendicularly incident to the coupling-in grating, the red light and the blue light are respectively incident to the coupling-in grating at the angle θ _r2、θ_b2, the diffraction angles of the red light, the green light and the blue light are respectively θ _r3、θ_g3、θ_b3 after being diffraction-modulated by the coupling-in region 131, and the step sizes are respectively l _r2、l_g2、l_b2.

As shown in fig. 9 and 10, the mixed light is refracted twice on the upper and lower surfaces of the prism, then the green light is perpendicularly incident to the coupling grating of the optical waveguide 130, and the red light and the blue light are respectively incident to the coupling grating at angles of θ _r2、θ_b2. The diffraction angles formed after the red light, the green light and the blue light are coupled into the grating to be modulated into +1 (or-1) order diffraction light are respectively theta _r3、θ_g3、θ_b3. Because the light beams emitted by the same pixel point have different coupling-out angles after being coupled out by the coupling-out area 132 due to the dispersion action of the first dispersion prism 123, the second dispersion prism 142 is added to deflect the coupling-out light of the same pixel point in the opposite direction, so that the light beams with different wavelengths of the same pixel point enter the eyes of the viewer at the same angle.

In order to make the first and second dispersion prisms 123 and 142 have opposite directions of deflection of the light beam, the first and second dispersion prisms 123 and 142 have the same refractive index and the same angle of the angle θ, and the directions of arrangement are opposite, as shown in fig. 11.

In addition, in order to increase the efficiency of the mixed light beam entering the first dispersion prism 123 and the light beam entering the second dispersion prism 142 at each wavelength, an antireflection film 152 may be provided on the light entrance surfaces of the first dispersion prism 123 and the second dispersion prism 142, thereby improving the light exit efficiency of the display module 100.

Optionally, the zero-field mixed beam exiting from the optical engine 110 has a predetermined angle β2 with the incident surface of the dispersion prism, so that the green light is perpendicularly incident into the coupling-in area 131.

The embodiment of the application also discloses an AR device comprising the display assembly 100. The AR device includes the same structure and advantages as the display assembly 100 in the previous embodiment. The structure and advantages of the display assembly 100 are described in detail in the foregoing embodiments, and are not described herein.

The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (10)

1. A display assembly, comprising: the light source device comprises a light machine, a dispersion element arranged on the light emitting side of the light machine and a light waveguide arranged on the light emitting side of the dispersion element, wherein the light emitting side of the light waveguide is provided with a dispersion compensation element, the light machine emits mixed light beams, the dispersion element deflects light beams with different wavelengths in the mixed light beams to different degrees, the light beams with different wavelengths in the same view field are enabled to enter the light waveguide coupling-in area at different angles and are coupled to the dispersion compensation element through the light waveguide coupling-out area, and the dispersion compensation element deflects the light beams with different wavelengths in the opposite direction to the deflection direction of the dispersion element and emits the emitted light beams forming the display assembly.

2. The display assembly of claim 1, wherein the dispersive element comprises a transmissive diffraction grating disposed between the light engine and the light guide in-coupling region, the transmissive diffraction grating deflecting blue, green, and red light in the mixed light beam to different extents to reduce diffraction angle differences formed between the red, green, and blue light in the in-coupling region.

3. The display assembly of claim 2, wherein the zero field mixed beam exiting the light engine has a predetermined angle with respect to a normal direction of the transmissive diffraction grating to cause the green light to be perpendicularly incident on the coupling-in region.

4. The display assembly of claim 1, wherein the dispersive element comprises a blazed grating, the light engine and the light guide are disposed on the same side of the blazed grating, the blazed grating reflecting the mixed light beam and deflecting blue, green and red light in the mixed light beam to different extents to reduce diffraction angle differences between the red, green and blue light formed at the light guide coupling-in region.

5. The display assembly of claim 4, wherein the bare engine-out zero field mixed beam is perpendicular to a grating plane of the blazed grating to cause the green light to be perpendicularly incident on the incoupling region.

6. A display assembly according to claim 3 or 5, wherein the dispersion compensating element is a transmissive diffraction element having the same period as the transmissive diffraction grating and opposite diffraction orders; the blazed grating has the same period as the transmission type diffraction element and has opposite diffraction orders.

7. The display module of claim 6, wherein the dispersion compensating element and the light exit side of the transmissive diffraction grating are bonded with an angle selective transmission film to prevent transmission of the zero order diffracted beam.

8. The display assembly of claim 1, wherein the dispersive element comprises a first dispersive prism disposed between the light machine and the light guide incoupling region, the first dispersive prism deflecting blue, green and red light in the mixed light beam to a different extent to reduce diffraction angle differences between the red, green and blue light formed at the light guide incoupling region, the dispersive compensation element comprising a second dispersive prism, the first and second dispersive prisms deflecting the light beam in opposite directions.

9. The display assembly of claim 8, wherein the light engine emits a zero field mixed light beam having a predetermined angle with respect to an entrance surface of the dispersive prism such that the green light is normally incident on the coupling-in region.

10. An AR device comprising the display assembly of any one of claims 1-9.