Optical system and near-to-eye display equipment

Abstract

The utility model discloses an optical system and a near-to-eye display device, the optical system comprises a display used for providing image source light, and also comprises a polarizing beam splitter, a transflective mirror and a curved mirror which are sequentially arranged along the propagation path of the image source light, and the transflective mirror is located on the human eye side; an absorption type polaroid is arranged on the side, close to the human eyes, of the transflective mirror and used for converting the polarization state of external light, so that the external light which penetrates through the absorption type polaroid and is reflected by the transflective mirror can be absorbed by the absorption type polaroid. The external light is finally converted and reflected into the light which can be absorbed by the absorption type polaroid, so that the purpose of eliminating environmental stray light is achieved, and the display effect is optimized.

Description

Technical Field

[0001] The utility model relates to the field of optical technology, and in particular to an optical system and a near-eye display device. Background Art

[0002] In recent years, near-eye display technology has been widely used and developed. Near-eye display technology allows the light emitted by the light source to enter the optical device, and then the optical device changes the direction of the light path before entering the human eye, combining virtual information with the real environment, so that users can observe enhanced visual effects through the display device. However, in practical applications, near-eye display imaging faces an important technical problem, namely the interference of stray light.

[0003] Stray light refers to unnecessary light signals generated during the augmented reality imaging process due to factors such as light scattering, reflection, and refraction. These stray light signals will reduce the clarity, brightness, and contrast of the near-eye display imaging system, thereby affecting the user's perception and experience of augmented reality content. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model provides an optical system and a near-eye display device to solve the problem in the prior art that stray light affects the user's perception and experience of augmented reality content during near-eye display imaging.

[0005] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0006] An optical system includes a display for providing image source light, and also includes a polarization beam splitter, a transflector and a curved reflector arranged in sequence along the propagation path of the image source light, wherein the transflector is located at the side of a human eye;

[0007] An absorbing polarizer is arranged on the side of the transflector close to the human eye. The absorbing polarizer is used to convert the polarization state of external light so that the external light passing through the absorbing polarizer and reflected by the transflector can be absorbed by the absorbing polarizer.

[0008] Optionally, the polarization beam splitter comprises a first substrate, a polarization beam splitter film is provided on the first substrate, and the polarization beam splitter film is used to reflect S-type polarized light;

[0009] The transmission axes of the polarization splitting film and the absorption polarizer are parallel.

[0010] Optionally, the transflective mirror comprises a second substrate, on which a first quarter-wave plate, a transflective film and a second quarter-wave plate are arranged in sequence along the propagation path of the image source light;

[0011] The first quarter wave plate is located on a side of the transflective film far from the absorbing polarizer, and the second quarter wave plate is located on a side of the transflective film close to the absorbing polarizer.

[0012] Optionally, an angle between the slow axis of the first quarter wave plate and the transmission axis of the polarization splitting film is 45° or 135°.

[0013] Optionally, the absorbing polarizer is used to convert the external light into P-type polarized light.

[0014] Optionally, the slow light axes of the second quarter wave plate and the first quarter wave plate are arranged to be orthogonal.

[0015] Optionally, the transflective film is plated on the second substrate, and the transmittance of the transflective film is 20-60%; the transmittance of the second substrate is 30-100%.

[0016] Optionally, the polarization beam splitter further comprises a first anti-reflection film located on a side of the first substrate away from the polarization beam splitter film, and the transflector further comprises a second anti-reflection film located on a side of the absorption polarizer away from the second substrate.

[0017] Optionally, the polarization beam splitter further comprises a third anti-reflection film located on a side of the polarization beam splitter film away from the first substrate, and the transflector further comprises a fourth anti-reflection film located on a side of the first quarter wave plate away from the second substrate.

[0018] Optionally, the curved reflector is a total reflector or a transmissive reflector.

[0019] The utility model also provides a near-eye display device, comprising the optical system as described in any one of the above items.

[0020] Compared with the prior art, the utility model has the following beneficial effects:

[0021] The utility model provides an optical system and a near-eye display device, which achieve the purpose of eliminating ambient stray light by finally converting and reflecting external light into light that can be absorbed by an absorption-type polarizing film, thereby optimizing the display effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1A schematic diagram of the structure of an optical system provided by the utility model;

[0024] Figure 2 A principle diagram of an optical path when a transflector is one of the structures in an optical system provided by the utility model;

[0025] Figure 3 A light path principle diagram of an optical system provided by the utility model when the polarization beam splitter has another structure;

[0026] Figure 4 A principle diagram of an optical path when a transflector is one of the structures in an optical system provided by the utility model;

[0027] Figure 5 A principle diagram of an optical path when the transflector and reflector in an optical system provided by the utility model is another structure;

[0028] Figure 6 The present invention provides another optical path principle diagram of an optical system.

[0029] In the above figure: 10, display; 20, polarization beam splitter; 21, first substrate; 22, polarization beam splitter film; 23, first anti-reflection film; 24, third anti-reflection film; 30, transflective mirror; 31, second substrate; 32, transflective film; 33, first quarter-wave plate; 34, second quarter-wave plate; 35, absorption polarizer; 36, second anti-reflection film; 37, fourth anti-reflection film; 40, curved reflector. DETAILED DESCRIPTION

[0030] In order to make the purpose, features and advantages of the utility model more obvious and easy to understand, the technical scheme in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the embodiment described below is only a part of the embodiment of the utility model, not all of the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0031] In the description of the present utility model, it is to be understood that when a component is considered to be "connected" to another component, it may be directly connected to the other component or there may be a centrally arranged component at the same time. When a component is considered to be "set on" another component, it may be directly set on the other component or there may be a centrally arranged component at the same time.

[0032] In addition, terms such as "long", "short", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only used to facilitate the description of the present invention. They do not indicate or imply that the device or component referred to must have this specific direction or operate with a specific direction structure, and should not be understood as a limitation of the present invention.

[0033] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0034] Please refer to Figure 1 An embodiment of the utility model provides an optical system, including a display 10 for providing image source light, and a polarization beam splitter 20, a transflective mirror 30 and a curved reflector 40 arranged in sequence along the propagation path of the image source light, the transflective mirror 30 is located on the human eye side, and an absorbing polarizer 35 is provided on the side of the transflective mirror 30 close to the human eye.

[0035] Specifically, in this embodiment, the polarization beam splitter 20 includes a first substrate 21 on which a polarization beam splitter film 22 is disposed. The polarization beam splitter film 22 is used to transmit P-type polarized light and reflect S-type polarized light. The transmission axes of the polarization beam splitter film 22 and the absorption polarizer 35 are parallel.

[0036] In addition, the transflective mirror 30 includes a second substrate 31, on which a first quarter-wave plate 33, a transflective film 32 and a second quarter-wave plate 34 are arranged in sequence along the propagation path of the image source light; the first quarter-wave plate 33 is located on the side of the transflective film 32 away from the absorbing polarizer 35, and the second quarter-wave plate 34 is located on the side of the transflective film 32 close to the absorbing polarizer 35.

[0037] Please refer to Figure 1 When displaying, the image source light emitted by the display 10 is S-type polarized light, the polarization beam splitter 20 reflects the S-type polarized light, passes through the first quarter wave plate 33 to become a first-handed circularly polarized light, and then is reflected by the transflective film 32 to become a second-handed circularly polarized light, and then passes through the first quarter wave plate 33 again to become P-type polarized light, the P-type polarized light passes through the polarization beam splitter 20 and is reflected by the reflective curved mirror, because the reflective curved mirror does not change the polarization state of the light, it is still P-type polarized light after being reflected back, and the P-type polarized light passes through the polarization beam splitter 20, the first quarter wave plate 33, the transflective film 32 and the second quarter wave plate 34 again, and is still P-type polarized light, and finally passes through the absorption polarizer 35 to be received by the human eye.

[0038] Please refer to Figure 2In the 1-1 optical path, the absorption principle of stray light in the absorption polarizer 35 is as follows: the external stray light becomes P-type polarized light after passing through the absorption polarizer 35, and the P-type polarized light becomes circularly polarized light after passing through the second quarter-wave plate 34. After being reflected by the transflective film 32, it is converted into S-type polarized light in the second quarter-wave plate 34 and absorbed by the absorption polarizer 35, thereby preventing the external ambient light from being reflected by the transflective film 32 to form stray light entering the human eye, thereby avoiding affecting the imaging effect.

[0039] It can be understood that, since the light that finally enters the human eye has been processed by the absorption polarizer 35 for stray light, the stray light in the light path cannot be received by the human eye, which reduces the influence of the stray light on the display effect, and effectively improves the final display effect;

[0040] Based on the above structure, when the image source light is reflected and transmitted multiple times by the polarization beam splitter 20, the transparent reflector 30 and the curved reflector 40, and finally enters the eye through the absorption polarizer 35, the utilization rate of the light is effectively improved, so that the brightness and visual effect of the display 10 are significantly enhanced.

[0041] Furthermore, the transflective mirror 30 includes a second substrate 31 , on which a first quarter wave plate 33 and a transflective film 32 are sequentially arranged along the propagation path of the image source light, and the transflective film 32 is plated on the second substrate 31 .

[0042] The angle between the slow axis of the first quarter wave plate 33 and the transmission axis of the polarization splitting film 22 is 45° or 135°. By precisely controlling the light path and polarization state, an image with high contrast and saturation can be obtained.

[0043] Furthermore, the transflector 30 further includes a second quarter wave plate 34, which is disposed on a side of the transflective film 32 away from the first quarter wave plate 33. The slow optical axes of the second quarter wave plate 34 and the first quarter wave plate 33 are orthogonal.

[0044] In this embodiment, when the second light enters the transflective mirror 30, it passes through the first quarter wave plate 33, the transflective film 32, the second substrate 31 and the second quarter wave plate 34 in sequence. By setting the second quarter wave plate 34, the system has a strong resistance to the interference of external light. This anti-interference performance can improve the visibility of the display 10 in scenes with complex lighting environments. At the same time, by setting the second quarter wave plate 34, the circularly polarized light after passing through the first quarter wave plate 33 can also be converted into P linear polarized light, so that all of it passes through the absorption type polarizer; it can be understood that the P polarized light reflected by the curved reflector 40 will become circularly polarized light after passing through the first quarter wave plate 33, and then directly pass through the absorption type polarizer, which will cause the brightness to decrease, and the degree of brightness decrease is about 50%; in this embodiment, the second quarter wave plate 34 is set to avoid the brightness decrease caused by the above situation, which is conducive to enhancing the display effect.

[0045] It is understandable that if Figure 3 As shown in the optical paths 2-1 and 2-2, when the display 10 emits linearly polarized light, it can be assumed to be S-type polarized light without loss of generality. The polarization beam splitter 20 reflects the S-type polarized light, passes through the first quarter-wave plate 33, and can be set to be left-handed circularly polarized light without loss of generality. It is then reflected by the transflective film 32 as right-handed circularly polarized light, and then passes through the first quarter-wave plate 33 to become P-type polarized light. At this time, since there is an interface between the polarization beam splitter film 22 and the first substrate 21 and the air, the surfaces of the polarization beam splitter film 22 and the first substrate 21 will reflect P-type polarized light. After the P-type polarized light is reflected by the surface of the polarization beam splitter film 22 and the surface of the first substrate 21, it is still P-type polarized light after passing through the first quarter-wave plate 33, the transflective film 32, the second substrate 31, and the second quarter-wave plate 34. After passing through the absorption polarizer 35, part of this part of the P-type polarized light will be received by the human eye to form stray light, thereby affecting the display effect.

[0046] To solve the aforementioned problem, in one implementation of the embodiment of the utility model, the polarization beam splitter 20 further includes a third anti-reflection film 24, and the third anti-reflection film 24 is disposed on the surface of the polarization beam splitter 22 close to the transparent reflector 30, and the polarization beam splitter 20 further includes a first anti-reflection film 23 disposed on the surface of the first substrate 21 away from the transparent reflector 30.

[0047] The provision of the first anti-reflection film 23 and the third anti-reflection film 24 can reduce the reflection of the polarization beam splitter 20 on the P-type polarized light, thereby further eliminating the stray light entering the human eye, and further optimizing the display effect.

[0048] It is understandable that if Figure 4In the optical path 3-1, the S-type polarized light emitted by the display 10 is reflected by the polarization splitter 20 and then passes through the first quarter-wave plate 33 to become a first-direction circularly polarized light. The first-direction circularly polarized light is reflected by the transflective film 32 as a second-direction circularly polarized light and then passes through the first quarter-wave plate 33 to become a P-type polarized light. The P-type polarized light is still P-type polarized light after being reflected on the surface of the first quarter-wave plate 33. Then, after the P-type polarized light passes through the transflective mirror 30, it may form stray light received by the human eye, resulting in the display effect being affected.

[0049] Based on the above problem, in this embodiment, a fourth anti-reflection film 37 is provided in the transflective mirror 30 to further eliminate the stray light.

[0050] like Figure 5 3-2 shows the optical path. In one implementation of the present embodiment, the transflector 30 includes a second anti-reflection film 36. The second anti-reflection film 36 is located on a side of the absorbing polarizer 35 away from the second substrate 31, and is used to reduce the reflection of the outer surface of the absorbing polarizer 35 on the external light.

[0051] In this embodiment, by providing the second anti-reflection film 36 and the fourth anti-reflection film 37 in the transflector 30, the reflection on the surface of the absorption polarizer 35 and the surface of the first quarter-wave plate 33 can be reduced, thereby optimizing the display effect.

[0052] In this embodiment, the first anti-reflection film 23, the second anti-reflection film 36, the third anti-reflection film 24 and the fourth anti-reflection film 37 can be attached to the installation surface by adhesive materials or by coating.

[0053] like Figure 6 In the 4-1 optical path, the external light becomes P-type polarized light after passing through the absorption polarizer 35. The P-type polarized light passes through the second quarter-wave plate 34, the second substrate 31, the transflective film 32, and the first quarter-wave plate 33 in sequence, and is still P-type polarized light. The P-type polarized light passes through the polarization beam splitter 20 and then is reflected by the reflective curved mirror. It passes through the polarization beam splitter 20 and the transflective mirror 30 again and is received by the human eye, which affects the display effect.

[0054] In order to further improve the optimization effect of stray light, the transmittance ratio of the transflective film 32 and the transmittance of the second substrate 31 are adjusted. When the transflective mirror 30 is at different transmittances, the intensity of light entering the human eye is as follows:

[0055]

[0056] Preferably, in this embodiment, the transmittance of the transflective film 32 is 20-60%; the second substrate 31 can be a glass sheet or a resin sheet, and the transmittance of the second substrate 31 is 30-100%. By optimizing the transmittance of the transflective mirror 30, a high-quality and comfortable image display effect can be provided, while also having strong anti-interference performance and enhancing the image expression.

[0057] Furthermore, the curved reflector 40 is a total reflector or a transmissive reflector. When the curved reflector 40 is a total reflector, it has a higher reflectivity, and can better retain and enhance the details and depth of the image, thereby improving the three-dimensionality and reality of the image, making the viewing experience more realistic.

[0058] Based on the aforementioned embodiments, the present invention further provides a near-eye display device, including the optical system provided in any of the above embodiments.

[0059] As described above, the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. An optical system, characterized in that: A display device for providing image source light, and also comprising a polarization beam splitter, a transflector and a curved reflector sequentially arranged along the propagation path of the image source light, wherein the transflector is located at the side of the human eye; An absorbing polarizer is arranged on the side of the transflector close to the human eye. The absorbing polarizer is used to convert the polarization state of external light so that the external light passing through the absorbing polarizer and reflected by the transflector can be absorbed by the absorbing polarizer.

2. The optical system according to claim 1, characterized in that The polarization beam splitter comprises a first substrate, on which a polarization beam splitter film is provided, and the polarization beam splitter film is used to reflect S-type polarized light; The transmission axes of the polarization splitting film and the absorption polarizer are parallel.

3. The optical system according to claim 2, characterized in that The transflector includes a second substrate, on which a first quarter wave plate, a transflective film and a second quarter wave plate are sequentially arranged along the propagation path of the image source light; The first quarter wave plate is located on a side of the transflective film far from the absorbing polarizer, and the second quarter wave plate is located on a side of the transflective film close to the absorbing polarizer.

4. The optical system according to claim 3, characterized in that The angle between the slow axis of the first quarter wave plate and the transmission axis of the polarization splitting film is 45° or 135°.

5. The optical system according to claim 4, characterized in that The slow light axes of the second quarter wave plate and the first quarter wave plate are arranged to be orthogonal.

6. The optical system according to claim 3, characterized in that The transflective film is plated on the second substrate, and the transmittance of the transflective film is 20-60%; the transmittance of the second substrate is 30-100%.

7. The optical system according to claim 3, characterized in that The polarization beam splitter further comprises a first anti-reflection film located on a side of the first substrate away from the polarization beam splitter film, and the transflector further comprises a second anti-reflection film located on a side of the absorption polarizer away from the second substrate.

8. The optical system according to claim 3, characterized in that The polarization beam splitter further comprises a third anti-reflection film located on a side of the polarization beam splitter away from the first substrate, and the transflector further comprises a fourth anti-reflection film located on a side of the first quarter wave plate away from the second substrate.

9. The optical system according to claim 1, characterized in that The curved reflector is a total reflector or a transmissive reflector.

10. A near-eye display device, characterized in that: Comprising the optical system according to any one of claims 1 to 9.

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