CN113985615A - Imaging module and head-mounted display device - Google Patents

Abstract

The invention discloses an imaging module and a head-mounted display device. Wherein, the formation of image module includes: the display screen is used for emitting light rays; the imaging lens is arranged in the light emergent direction of the display screen; the phase delay corrector is arranged on the display screen or the imaging lens, and phase delay compensation shafts of the phase delay corrector are distributed in a non-rotational symmetry mode. The technical scheme of the invention can reduce the generation of stray light and ensure that a user obtains a clear imaging picture.

Description

Imaging module and head-mounted display device

The present invention claims priority from the chinese patent application, entitled "imaging module and head mounted display device," filed on 29/6/2021, application No. 202110739944.0, the entire contents of which are incorporated herein by reference.

Technical Field

The invention relates to the technical field of optical display, in particular to an imaging module and a head-mounted display device.

Background

In order to reduce the volume of the whole Head mounted Display device (Head mounted Display), a catadioptric optical path is usually designed inside the Head mounted Display device, so that light can pass through the Head mounted Display device many times in a limited space. In order to ensure smooth refraction and reflection of light, the light needs to be converted into a uniform polarization state. However, when light rays of the display screen pass through some optical devices, the incident angle of the light rays can be changed, the light rays can be converted into different polarization states due to different incident angles, stray light is formed by the light rays different from the uniform polarization state, and the imaging definition can be influenced by the stray light.

Disclosure of Invention

Based on this, to the problem that stray light can be formed to the light of current different incident angles, stray light can lead to the formation of image definition to reduce, it is necessary to provide an imaging module and wear display device, aim at can reducing stray light's production, guarantee that the user obtains clear formation of image picture.

In order to achieve the above object, the present invention provides an imaging module, which includes:

the display screen is used for emitting light rays;

the imaging lens is arranged in the light emergent direction of the display screen; and

the phase delay corrector is arranged on the display screen or the imaging lens, and the phase delay of the phase delay corrector is distributed in a non-rotational symmetrical mode.

Optionally, the phase delay corrector comprises a phase increasing axis and a phase decreasing axis, and the phase increasing axis and the phase decreasing axis are arranged at an included angle.

Optionally, the maximum direction of the phase increase axis to increase the phase delay is orthogonal to the maximum direction of the phase decrease axis to decrease the phase delay.

Optionally, the phase delay corrector further includes a first shaft and a second shaft having a delay angle of zero, the first shaft is located between the phase increasing shaft and the phase decreasing shaft, the second shaft is located between the phase increasing shaft and the phase decreasing shaft, and the first shaft and the second shaft are disposed at an included angle.

Optionally, the phase delay corrector is disposed on the light incident surface of the imaging lens, and the imaging module further includes:

the first phase retarder is arranged on one side of the phase retardation corrector, which is far away from the imaging lens; and

and the linear deflector is arranged on one side of the first phase retarder, which faces away from the imaging lens.

Optionally, the imaging module further comprises:

a beam splitter disposed between the phase delay corrector and the imaging lens;

the second phase retarder is arranged between the light splitting piece and the imaging lens; and

the polarization reflector is arranged on the light emergent surface of the imaging lens, and the transmission axis of the linear polarizer is orthogonal to that of the polarization reflector.

Optionally, the first and second phase retarders are both quarter-wave plates.

Optionally, the imaging module further includes a third bit phase retarder, and the third bit phase retarder is disposed between the line deflector and the display screen.

Optionally, the imaging module further includes a positive lens, and the positive lens is disposed on a side of the imaging lens away from the display screen;

defining the direction perpendicular to the optical axis of the imaging module as a height direction, the height of the imaging lens as D1, and the height of the positive lens as D2, then: d2 < D1.

In addition, in order to solve the above problem, the present invention further provides a head-mounted display device, which includes a housing and the imaging module as described above, where the imaging module is disposed on the housing.

In the technical scheme provided by the invention, the display screen emits light rays, and the light rays irradiate towards the imaging lens. The imaging module has an optical axis, and the incident angle of light rays around the optical axis of the imaging module can be changed differently. Different incident angles can form different polarization states, and the light rays compensate the changed incident angles after passing through the phase delay corrector. In order to meet the requirement that light rays with different incident angles can be subjected to phase compensation, the phase delays of the phase delay correctors are arranged in a non-rotational symmetric distribution mode, and therefore the phase delay correctors can perform phase compensation at corresponding positions in the direction of increasing the phase delay or decreasing the phase delay. The light after phase compensation is emitted to form a uniform polarization state, so that the generation of stray light is reduced, and a user is ensured to obtain a clear imaging picture.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the structures shown in the drawings without creative efforts.

FIG. 1 is a schematic structural diagram of an imaging module according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a portion of the imaging lens of FIG. 1;

FIG. 3 is a schematic high-level view of the imaging lens and positive lens of FIG. 1;

FIG. 4 is a schematic diagram of a phase compensation distribution of the phase delay corrector in FIG. 1;

FIG. 5 is a graph of the modulation transfer function of the imaging module of FIG. 1 at 450 nm;

FIG. 6 is a graph of the modulation transfer function at 540nm for the imaging module of FIG. 1;

FIG. 7 is a graph of the modulation transfer function at 610nm for the imaging module of FIG. 1.

The reference numbers illustrate:

reference numerals	Name (R)	Reference numerals	Name (R)
				10	Display screen	50	Line deflector
101	Human eye	60	Light splitting piece
				110	Light ray	70	Second phase delayer
20	Imaging lens	80	Polarizing reflector
				30	Phase delay corrector	90	Third bit phase delayer
40	First phase delayer	04	Positive lens

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that all the directional indicators (such as up, down, left, right, front, and rear … …) in the embodiment of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawing), and if the specific posture is changed, the directional indicator is changed accordingly.

In addition, the descriptions related to "first", "second", etc. in the present invention are only for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In the present invention, unless otherwise expressly stated or limited, the terms "connected," "secured," and the like are to be construed broadly, and for example, "secured" may be a fixed connection, a removable connection, or an integral part; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, the technical solutions in the embodiments of the present invention may be combined with each other, but it must be based on the realization of those skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination of technical solutions should not be considered to exist, and is not within the protection scope of the present invention.

In the related art, the head-mounted display device can provide virtual experience for a user, the volume of the current head-mounted display device is large, and in order to reduce the volume of the head-mounted display device, a catadioptric light path is designed in the head-mounted display device, so that light rays are transmitted back and forth for multiple times in a limited space. Meanwhile, in order to ensure smooth refraction and reflection of light, the light needs to be converted into a uniform polarization state. However, when light rays of the display screen pass through some optical devices, the incident angle of the light rays can be changed, especially when the light rays pass through some polarization conversion devices, the light rays can be converted into different polarization states due to different incident angles, stray light is formed by the light rays different from the uniform polarization state, and the imaging definition can be influenced by the stray light.

In order to solve the above problem, referring to fig. 1 and 2, the present invention provides an imaging module, which includes: a display screen 10, an imaging lens 20, and a phase delay corrector 30. The display screen 10 is used for emitting light 110, the imaging lens 20 is disposed in the light emitting direction of the display screen 10, and the phase delay corrector 30 may be disposed on the display screen 10 or on the imaging lens 20.

Among them, the light emitting principle of the display screen 10 includes various principles. For example, the principle of the display screen 10 includes an lcd (liquid Crystal display) lcd, or an led (Light Emitting Diode), an OLED (Organic Light-Emitting Diode), a Micro-OLED (Micro-Organic Light-Emitting Diode), an uled (ultra Light Emitting Diode), or a dmd (digital Micro mirror device) digital Micromirror chip.

The imaging lens 20 is arranged in the light-emitting direction of the display screen 10; the imaging lens 20 is used to magnify and resolve the light 110, and the light-emitting surface area of the display screen 10 is small, for example, in a VR (Virtual Reality) display device or an AR (Augmented Reality) display device, the size of the display screen 10 is only a few inches. In order to ensure that the user obtains the enlarged display, the light 110 needs to be enlarged, and the user is ensured to obtain a clear image through the imaging lens 20. The imaging lens 20 may be a single lens or a combination of a plurality of lenses.

The phase delay corrector 30 is provided on the display screen 10 or on the imaging lens 20. The display screen 10 has a light exit surface from which the light 110 exits, and the phase delay corrector 30 may be disposed on the light exit surface of the display screen 10. The imaging lens 20 has an incident surface into which the light ray 110 enters and an emergent surface from which the light ray 110 exits, and the phase delay corrector 30 may be disposed on the incident surface of the imaging lens 20 or on the emergent surface of the imaging lens 20. In the case where the imaging lens 20 has a plurality of mirror combinations, the phase retardation corrector 30 may be provided between the plurality of mirror combinations.

The phase delays of the phase delay corrector 30 are not rotationally symmetric. Specifically, different angles of incidence of the light ray 110 may result in different phase delays of the light ray 110, or it is understood that different angles of incidence result in a possible increase or decrease in the phase delay of the light ray 110, or that an increase in the phase delay and a decrease in the phase delay occur simultaneously in different directions. The increase or decrease of the phase of the light ray 110 passing through the phase delay corrector is compensated and corrected. Further, the phase delay of the light ray 110 with increased phase delay is decreased after passing through the phase delay corrector, and the phase delay of the light ray 110 with decreased phase delay is increased after passing through the phase delay corrector. It is noted that the non-rotationally symmetric distribution of the phase delay corrector may be achieved by varying the thickness of the phase delay corrector 30, such as by decreasing the thickness at locations where the phase delay increases and increasing the thickness at locations where the phase delay decreases. For example, when the light ray 110 is emitted to the phase delay corrector 30, an o light and an e light are formed on the light incident surface of the phase delay corrector, the traveling speed of the o light is fast, the traveling speed of the e light is slow, and the time for the e light to reach the light emitting surface of the phase delay corrector is different by changing the thickness, so that the phase delay is changed. In addition, the refractive index of the material at different positions of the phase retardation corrector 30 may be changed to generate a refractive index difference with respect to o-light and e-light, and the phase retardation may be adjusted according to the magnitude of the refractive index difference. The refractive index difference is increased at the position where the phase delay needs to be increased, so that the speed of reaching the e light is slowed down, the time of reaching the light-emitting surface of the e light is prolonged, and the phase delay is increased. The refractive index difference is increased at the position where the phase delay needs to be reduced, so that the speed of reaching the e light is reduced, the time of reaching the light-emitting surface of the e light is shortened, the phase delay is increased, and the phase delay is changed. The phase delay corrector non-rotation symmetrical distribution is completed by changing the thickness of different positions or the refractive index of materials at different positions. It is of course also possible that the thickness and the material refractive index combine to achieve a non-rotationally symmetric distribution of the phase delay corrector.

In the solution proposed in this embodiment, the display screen 10 emits the light 110, and the light 110 is emitted to the imaging lens 20. The imaging module has an optical axis, and the incident angle of the light 110 around the optical axis of the imaging module varies differently. Different incident angles form different polarization states, and the light 110 passes through the phase delay corrector and then compensates for the changed incident angles. In order to satisfy the requirement that the light rays 110 with different incident angles can be phase-compensated, the phase delays of the phase delay correctors are arranged in a non-rotational symmetric distribution, so that the phase delay correctors can perform phase compensation at corresponding positions for the directions of increasing the phase delay or decreasing the phase delay. The phase-compensated light 110 forms a uniform polarization state after being emitted, thereby reducing the generation of stray light and ensuring that a user obtains a clear imaging picture.

Referring to fig. 4, in the above embodiment, a schematic diagram of the increase and decrease of the phase retardation compensation can be formed on the surface of the phase retardation corrector 30 by 360 ° with the optical axis of the imaging module as the symmetry axis. The X axis is the horizontal axis and the Y axis is the vertical axis, and the distance in both directions is normalized and the phase delay is normalized. The change of the incident angle is from positive to negative, and the change of the angle is from large to small, so that the increase of the phase delay has a maximum direction, the decrease of the phase delay has a maximum direction, and the position between the two is that the increase of the phase delay and the decrease of the phase delay gradually change. In order to compensate for the phase at the maximum position where the phase delay increases and the maximum position where the phase delay decreases, the phase delay corrector includes a phase increasing axis corresponding to the position where the phase delay needs to be decreased and a phase decreasing axis corresponding to the position where the phase delay needs to be increased.

Further, referring to fig. 2, it can be seen that the phase delay compensator crosses the phase increasing axis and the phase decreasing axis, and the maximum direction of increasing the phase delay on the phase increasing axis and the maximum direction of decreasing the phase delay on the phase decreasing axis are orthogonal to each other. The orthogonal intersection point is located at the optical axis position, the orthogonal description is that the included angle is 90 degrees, and the angle formed by the increasing direction of the phase retardation to the decreasing direction of the phase retardation and the angle formed by the decreasing direction of the phase retardation to the increasing direction of the phase retardation are the same.

Further, the incident angle of the light ray 110 is sometimes unchanged, and there is no need to compensate for the phase retardation of the light ray 110 at this position. The phase delay corrector also comprises a first shaft and a second shaft, wherein the delay angle is zero, the first shaft is positioned between the phase increasing shaft and the phase decreasing shaft, the second shaft is positioned between the phase increasing shaft and the phase decreasing shaft, and the first shaft and the second shaft are arranged in an included angle. For example, the first axis and the second axis form an angle of 90 °, the first axis extends horizontally, and the second axis extends vertically. Of course, after the imaging module rotates, the first shaft and the second shaft also rotate synchronously. It should be noted that, in some specifications of imaging modules, the increase or decrease of the phase is not strictly gradual from large to small, and sometimes the change may be too fast or too slow, so that the included angle between the first axis and the second axis is shifted by about 90 °, and the included angle between the first axis and the second axis may be smaller than 90 ° or larger than 90 °.

In an embodiment of the present application, the phase delay corrector 30 is disposed on the light incident surface of the imaging lens 20, and the imaging module further includes: a first bit phase retarder 40 and a line deflector 50. The light 110 emitted from the display screen 10 may have a plurality of polarization states, such as circularly polarized light, elliptically polarized light, or linearly polarized light, or may be one of the three or a combination of two of the light 110, or may be natural light. After passing through the linear polarizer 50, the light rays 110 are all converted into linearly polarized light with the same polarization direction, and the polarization states of the light rays 110 are uniform, so that the refraction and reflection of the light rays 110 are conveniently completed next. The linear polarizer 50 is used for converting the passing light 110 into linearly polarized light, and the first phase retarder 40 is used for converting the passing linearly polarized light into circularly polarized light or elliptically polarized light, and also used for converting the passing circularly polarized light or elliptically polarized light into linearly polarized light. The first phase retarder 40 is arranged on the side of the phase retardation corrector 30 facing away from the imaging lens 20; the linear polarizer 50 is arranged on the side of the first phase retarder 40 facing away from the imaging lens 20. The light 110 emitted from the display screen 10 sequentially passes through the linear polarizer and the first phase retarder 40, and the phase retardation corrector 30 can compensate for the change because the incident angle of the light 110 emitted from the display screen 10 has been changed when the light is transmitted to the linear polarizer and the first phase retarder 40. The first phase retarder 40 has a fast axis and a slow axis, and the phase retardation increases in the fast axis direction and decreases in the slow axis direction. To compensate for the phase delay, the phase increasing axis corresponds to the slow axis setting of the first phase retarder 40 and the phase decreasing axis corresponds to the fast axis setting of the first phase retarder 40. In addition, since the first phase retarder 40 is disposed between the line polarizer 50 and the imaging lens 20, the optical surface of the first phase retarder 40 avoids contact with air, reducing the optical medium passing therethrough, thereby reducing reflection of the light 110. It is further noted that the line polarizer 50 is disposed on a surface of the first phase retarder 40 facing away from the imaging lens 20. When the light ray 110 encounters the line deflector 50, the direction of reflection is also away from the human eye 101. It will also be appreciated that the light ray 110 when directed from the display screen 10 towards the first phase retarder 40 is also directed away from the human eye 101 even if there is a reflection at the surface of the first phase retarder 40. Therefore, under the condition that the first phase retarder 40 avoids contacting with air to reduce reflection, the direction of reflection is still towards the direction far away from the human eyes 101, and the reflected light 110 is further reduced to enter the human eyes 101, namely stray light is reduced, so that a user can obtain a clear display picture.

Further, in order to effectively reduce the volume of the imaging module, the light 110 is refracted and reflected inside the imaging module. Therefore, the imaging module further comprises: a beam splitter 60, a second phase retarder 70 and a polarizing reflector 80. The beam splitter 60 is provided between the phase retardation corrector 30 and the imaging lens 20; the second phase retarder 70 is arranged between the light splitting part 60 and the imaging lens 20; the polarizing reflector 80 is disposed on the light-emitting surface of the imaging lens 20, and the transmission axis of the linear polarizer 50 is orthogonal to the transmission axis of the polarizing reflector 80. When the light ray 110 passes through the light splitting element 60, a part of the light ray 110 is reflected, and another part of the light ray 110 is transmitted, wherein the reflection and transmission ratio can be 1:1, 2:1, 1:2, and the like, for example, the light splitting element 60 can be a transflective film. The light splitting member 60 may be attached between the second phase retarder 70 and the phase retardation corrector 30 by an optical adhesive. The light-splitting component 60 may also be coated on the surface of the second phase retarder 70 or on the surface of the phase retardation corrector 30. The second phase retarder 70 is arranged between the light splitting component 60 and the imaging lens 20, and an included angle between an optical axis of the second phase retarder 70 and a transmission axis of the linear polarizer 50 is 45 degrees, wherein the included angle can be positive 45 degrees or negative 45 degrees; the second phase retarder 70 is also a film structure, and the second phase retarder 70 may be adhered between the light-splitting member 60 and the imaging lens 20 by an optical adhesive. The light-splitting component 60 may also be coated on the surface of the second phase retarder 70 or on the surface of the phase retardation corrector 30.

The polarizing reflector 80 is disposed on the light-emitting surface of the imaging lens 20, and the transmission axis of the linear polarizer 50 is orthogonal to the transmission axis of the polarizing reflector 80. Similarly, the polarizing reflector 80 may be a film structure, and the polarizing reflector 80 may be attached to the imaging lens 20 by an optical adhesive. The light-splitting component 60 can also be coated on the surface of the imaging lens 20 by a coating method. In addition, the transmission axis of the linear polarizer 50 is orthogonal to the transmission axis of the polarizing reflector 80, so that the light 110 can be refracted and reflected inside the imaging module. Specifically, the display screen 10 emits the light 110, the emitted light 110 sequentially passes through the polarizer 50 and the first phase retarder 40, the polarization state of the light 110 is circularly polarized light, and the light 110 is emitted to the light splitter 60 after being corrected by the phase retardation corrector 30. The light rays 110 pass through the light-splitting element 60, one part of the light rays 110 is transmitted, and the other part of the light rays 110 is reflected. The light 110 transmitted through the light splitter 60 continues to propagate and passes through the second phase retarder 70, the polarization state of the circularly polarized light 110 is changed, and the circularly polarized light is converted into linearly polarized light. The linearly polarized light 110 is transmitted through the imaging lens 20 toward the polarizing reflector 80. At this time, the light ray 110 is reflected with the vibration direction of the linearly polarized light different from the transmission axis direction of the polarizing reflector 80. The reflected light 110 passes through the imaging lens 20, the second phase retarder 70, and is again directed to the light splitting member 60. When the light ray 110 passes through the light splitting element 60 again, the light ray 110 is partially reflected toward the second phase retarder 70. At this time, the light 110 is converted into circularly polarized light, and after reflection, the rotation direction of the light 110 is changed, and the light 110 is converted into linearly polarized light again after passing through the second phase retarder 70. At this time, the polarization direction of the linearly polarized light is the same as the transmission axis direction of the polarizing reflector 80, and in this process, the diameter of the optical path is continuously enlarged. Through multiple refraction and reflection of the light rays 110, the amplified transmission of the image is realized in a limited space, and the volume of the imaging module is favorably reduced.

Further, to effectively switch the light ray 110 between circular and linear polarizations, both the first and second phase retarders 40 and 70 are quarter-wave plates. After the light 110 passes through the quarter-wave plate, the linearly polarized light is converted into circularly polarized light, and the circularly polarized light is converted into linearly polarized light. In addition, the quarter-wave plate is of a film structure, so that the imaging module is convenient to reduce the size. In addition, the quarter-wave plate can be attached by adopting an optical adhesive or a film coating mode.

In order to further reduce the stray light, in an embodiment of the present invention, after the light 110 emitted from the display screen 10 encounters the linear polarizer 50, a portion of the light 110 is reflected in addition to the light 110 transmitted through the linear polarizer 50, and the portion of the light 110 is reflected again after being emitted to the display screen 10, which is prone to generate the stray light affecting the display screen 10. In order to further reduce stray light, the imaging module further includes a third phase retarder 90, the third phase retarder 90 is disposed between the line polarizer 50 and the display screen 10, and an included angle between an optical axis of the third phase retarder and a transmission axis of the line polarizer 50 is 45 °. Wherein the third phase retarder 90 may also be a quarter-wave plate. The light 110 reflected by the linear polarizer 50 is converted into circularly polarized light through the third phase retarder 90, and after being reflected by the display screen 10, the rotation direction of the circularly polarized light is changed, and the left rotation is changed into the right rotation, or the right rotation is changed into the left rotation. After the light 110 passes through the third phase retarder again, the circularly polarized light is converted into linearly polarized light, the polarization direction of the linearly polarized light is perpendicular to the transmission axis of the linear polarizer 50, and the light 110 cannot pass through the linear polarizer 50, so that the generation of stray light is reduced.

Referring to fig. 3, in order to reduce the volume of the imaging module, the imaging module further includes a positive lens 04, and the positive lens 04 is disposed on a side of the imaging lens 20 away from the display screen 10; the positive lens 04 has positive power, and the light rays 110 converge after passing through the positive lens 04 to exit at the position of the human eye 101. Defining the direction perpendicular to the optical axis of the imaging module as the height direction, the height of the imaging lens 20 as D1, and the height of the positive lens 04 as D2, then: d2 < D1. It follows that the effective height dimension of the positive lens 04 is smaller than the effective height dimension of the imaging lens 20. Thus, the light ray 110 needs to be bent at a large angle toward the optical axis of the imaging module when the light ray is emitted to the positive lens 04. And because the focal power of the positive lens 04 is positive, the position where the light ray 110 converges is closer to the imaging module, so the imaging position is closer. The whole volume of formation of image module is more small and exquisite, also is convenient for the user to use.

In the above embodiment, the position of the imaging lens 20 is at least two, the first case is that the imaging lens 20 is disposed on the light-emitting surface of the display screen 10. Thus, the light 110 directly enters the imaging lens 20 after being emitted through the display screen 10, and the light 110 is prevented from being transmitted in the atmosphere, so that the optical medium through which the light 110 passes is reduced, the reflection of the light 110 is further reduced, and the absorption of the light 110 by the optical medium is reduced.

In addition to this, the second case is that the imaging lens 20 is disposed spaced apart from the display screen 10. Therefore, the propagation distance of the light 110 can be increased, the optical path is increased, the light 110 has a sufficient refraction and reflection path, and the light 110 is sufficiently amplified, analyzed and imaged.

Further, there are various types of arrangement of the imaging lens 20, including specifically that the imaging lens 20 is one of a plano-convex lens, a meniscus lens, or a biconvex lens. When the imaging lens 20 is a plano-convex lens, the light incident surface of the imaging lens 20 is a plane, and the light emitting surface of the imaging lens 20 is a convex surface. When the imaging lens 20 is a meniscus lens, the concave-convex lens may be a meniscus lens, the light incident surface of the imaging lens 20 is a concave surface, and the light emergent surface of the imaging lens 20 is a convex surface. When the imaging lens 20 is a biconvex lens, the light incident surface of the imaging lens 20 and the light emitting surface of the imaging lens 20 are convex surfaces. The light emitting surface of the imaging lens 20 is convex, so that the light 110 is effectively deflected to the position of the human eye 101.

The invention also provides a head-mounted display device, which comprises a shell and the imaging module, wherein the imaging module is arranged on the shell. The casing can provide a installation space who supports the formation of image module, and the formation of image module sets up in the casing, so can avoid external environment's steam or dust to fall into the inside of formation of image module.

The embodiments of the head-mounted display of the present invention can refer to the embodiments of the imaging module, and are not described herein again.

The first table lists the specific parameters of one embodiment of the imaging module and gives the calculated optical surface correspondence coefficients.

Watch 1

In addition, referring to the above embodiments, fig. 5, fig. 6, and fig. 7 are Modulation Transfer Function (MTF) graphs of the imaging module in this embodiment at 450nm, 540nm, and 610nm, respectively, where the MTF graphs refer to a relationship between a modulation degree and a logarithm of lines per millimeter in an image, and are used for evaluating a fine feature restoring capability of a scene. It can be seen that at a spatial frequency of 50 line pairs per millimeter at a wavelength of 540nm, the imaging module MTF values are higher than 0.7, and at wavelengths of 450nm and 610nm, the imaging module MTF values are higher than 0.35. In the main field angle range, the MTF value is greater than 0.7, and the resolution is good.

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications and equivalents of the present invention, which are made by the contents of the present specification and the accompanying drawings, or directly/indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims (10)

1. The utility model provides an imaging module, its characterized in that, imaging module includes:

the display screen is used for emitting light rays;

the imaging lens is arranged in the light emergent direction of the display screen; and

the phase delay corrector is arranged on the display screen or the imaging lens, and the phase delay of the phase delay corrector is distributed in a non-rotational symmetrical mode.

2. The imaging module of claim 1, wherein the phase delay corrector comprises a phase addition axis and a phase subtraction axis, the phase addition axis and the phase subtraction axis being disposed at an angle.

3. The imaging module of claim 2, wherein a maximum direction of the phase increase axis to increase phase delay is orthogonal to a maximum direction of the phase decrease axis to decrease phase delay.

4. The imaging module of claim 2, wherein the phase delay corrector further comprises a first axis and a second axis having a delay angle of zero degrees, the first axis being located between the phase increment axis and the phase decrement axis, the second axis being located between the phase increment axis and the phase decrement axis, the first axis and the second axis being disposed at an angle.

5. The imaging module of any of claims 1 to 4, wherein the phase delay corrector is disposed at the light incident surface of the imaging lens, the imaging module further comprising:

the first phase retarder is arranged on one side of the phase retardation corrector, which is far away from the imaging lens; and

and the linear deflector is arranged on one side of the first phase retarder, which faces away from the imaging lens.

6. The imaging module of claim 5, further comprising:

a beam splitter disposed between the phase delay corrector and the imaging lens;

the second phase retarder is arranged between the light splitting piece and the imaging lens; and

the polarization reflector is arranged on the light emergent surface of the imaging lens, and the transmission axis of the linear polarizer is orthogonal to that of the polarization reflector.

7. The imaging module of claim 6 wherein the first phase retarder and the second phase retarder are each quarter-wave plates.

8. The imaging module of claim 5 further comprising a third bit phase retarder disposed between the line polarizer and the display screen.

9. The imaging module of any of claims 1 to 4, further comprising a positive lens disposed on a side of the imaging lens facing away from the display screen;

defining the direction perpendicular to the optical axis of the imaging module as a height direction, the height of the imaging lens as D1, and the height of the positive lens as D2, then: d2 < D1.

10. A head-mounted display device, comprising a housing and the imaging module according to any one of claims 1 to 9, wherein the imaging module is disposed on the housing.

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