Pupil expanding system and display equipment

Abstract

The utility model discloses a pupil expanding system and a display device, and relates to the technical field of optics. The pupil expanding system provided by the utility model comprises a collimation system and a reflection grating which are sequentially arranged along the transmission direction of a light beam emitted by a light source. A light beam emitted by the light source is collimated into parallel light through the collimation system, the parallel light enters the reflection grating, and then the parallel light is emitted after passing through the reflection grating. According to the pupil expansion system, pupil expansion of light beams is achieved through the reflection grating, so that a user can observe image information in a larger range; compared with the function of realizing pupil expansion through an optical waveguide, the pupil expansion system has the advantages that the reflection grating is used, the coupling-in and coupling-out processes are avoided, the energy loss is reduced, the energy utilization rate is improved, and the experience feeling when a user uses equipment comprising a pupil expansion system is improved; and the reflection grating is obliquely arranged relative to the first parallel light, so that the light beams passing through the reflection grating can enter human eyes.

Description

Technical Field

[0001] The utility model relates to the technical field of optics, in particular to a pupil expansion system and a display device. Background Art

[0002] Currently, pupil expansion in optical products on the market is primarily achieved through waveguide technology. By placing coupling-in and coupling-out gratings on waveguide lenses, light is coupled into the lens through the coupling-in grating. Within the glass substrate, the light is transmitted to the coupling-out grating of the waveguide through total internal reflection. After dilating the pupil through the coupling-out grating, light is emitted, expanding the exit pupil aperture. Waveguide lenses offer advantages such as expanding the eye's range of motion and reducing system size.

[0003] However, due to the principle of optical waveguide imaging, energy loss of both the coupling-in grating and the coupling-out grating during transmission is difficult to avoid, and the optical energy utilization efficiency is low.

[0004] It can be seen that providing a new pupil dilation technology to improve energy utilization and enhance user experience is a technical problem that people in this field urgently need to solve. Utility Model Content

[0005] The utility model provides a pupil expansion system and a display device to solve the technical problem that energy utilization rate in the pupil expansion system is low and affects user experience.

[0006] In order to solve the above technical problems, the utility model provides a pupil expansion system, comprising: a light source, a collimation system and a reflective grating;

[0007] The light source is used to emit a light beam;

[0008] The collimation system and the reflection grating are sequentially located in the transmission direction of the light beam emitted by the light source;

[0009] The collimation system is used to collimate the light beam emitted by the light source to form a first parallel light, which is incident on the reflection grating and emitted as a second parallel light after being reflected by the reflection grating; wherein the reflection grating is placed obliquely relative to the first parallel light.

[0010] Exemplarily, the inclination angle of the reflection grating relative to the first parallel light is less than or equal to 45°.

[0011] Exemplarily, an incident angle φ of the first parallel light when incident on the reflection grating satisfies the following conditions: a tangent of the incident angle φ is a preset ratio of the beam aperture of the second parallel light to the beam aperture of the first parallel light; and an angle between the first parallel light and the reflection grating is 90°-φ. Exemplarily, the reflection grating is a one-dimensional reflection grating.

[0012] Exemplarily, the grating constant of the reflection grating matches the wavelength of the light source.

[0013] Exemplarily, the light source includes a first light source and a second light source, and the pupil expansion system further includes: a light combining element;

[0014] The light combining element is located on the optical path between the light source and the collimating system.

[0015] Exemplarily, the first light source and the second light source are light sources of the same type or light sources of different types; wherein the light source type includes at least a point light source type and an image source type.

[0016] Exemplarily, a holographic sheet is also included;

[0017] The hologram is located on the light-emitting side of the reflection grating.

[0018] Exemplarily, the hologram is attached to the reflective grating by means of embossing, etching, masking or exposure and development.

[0019] Exemplarily, the collimating system is a single lens, a combined lens, or a curved reflector.

[0020] Exemplarily, an adjustment mechanism is also included;

[0021] The adjustment mechanism is in contact with the reflection grating and is used to change the placement angle of the reflection grating.

[0022] Exemplarily, it also includes an electro-optical modulator;

[0023] The electro-optic modulator is located between the light source and the collimation system, and is used to adjust the phase distribution or amplitude of the light beam.

[0024] In order to solve the above technical problems, the present invention also provides a display device, including the above pupil expansion system.

[0025] The pupil expansion system provided by the present invention includes: a collimation system and a reflection grating placed in sequence along the transmission direction of the light beam emitted by the light source. The light beam emitted by the light source is collimated into parallel light by the collimation system to be incident on the reflection grating, and then emitted as parallel light after passing through the reflection grating. In this pupil expansion system, the pupil expansion of the light beam is achieved by using a reflection grating, so that the user can observe image information in a wider range; and compared with the function of achieving pupil expansion through an optical waveguide, the reflection grating used in the present invention does not have the process of coupling in and out, which reduces energy loss, improves energy utilization, and improves the user experience when using a device containing a pupil expansion system; and the reflection grating is placed at an angle relative to the first parallel light, ensuring that the light beam passing through the reflection grating can enter the human eye.

[0026] In addition, the present invention also provides a display device, including the above-mentioned pupil expansion system, which has the same beneficial effects as the above-mentioned pupil expansion system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 A schematic diagram of a pupil expansion system provided in a first embodiment of the present utility model;

[0029] Figure 2 A schematic diagram of a pupil expansion system provided in a second embodiment of the present invention;

[0030] Figure 3 A schematic diagram of a reflective grating diffraction provided by an embodiment of the present utility model;

[0031] Figure 4 A schematic diagram of another reflective grating diffraction provided by an embodiment of the present utility model;

[0032] Figure 5 This is a schematic diagram of a pupil expansion system provided in the third embodiment of the present invention.

[0033] The reference numerals are as follows:

[0034] 1- Light source; 2- Collimation system; 3- Reflection grating; 4- Human eye; 5- Hologram; Curved reflector-21. DETAILED DESCRIPTION

[0035] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0036] The core of the utility model is to provide a pupil expansion system and a display device to solve the technical problem of low energy utilization in the pupil expansion system, which affects the user experience.

[0037] In order to enable those skilled in the art to better understand the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific implementation methods. Figure 1This is a schematic diagram of a pupil expansion system provided by the first embodiment of the present invention, as shown in FIG. Figure 1 As shown, it includes: a light source 1, a collimation system 2 and a reflection grating 3;

[0038] The light source 1 is used to emit a light beam;

[0039] The collimation system 2 and the reflection grating 3 are sequentially located in the transmission direction of the light beam emitted by the light source 1;

[0040] The collimation system 2 is used to collimate the light beam emitted by the light source 1 to form a first parallel light. The first parallel light is incident on the reflection grating 3 and is reflected by the reflection grating 3 before being emitted as a second parallel light and entering the human eye 4 .

[0041] There are no limitations on light source 1; it can be a single light source or multiple light sources. Specifically, light source 1 can be, but is not limited to, a laser light source. It can also be a light-emitting diode (LED) light source, a display light source, a light source with a graticule pattern, or a display light source with a digital image. When light source 1 is a microdisplay, the microdisplay can carry long-infrared thermal imaging information, medium-wave infrared information, short-wave infrared information, near-infrared night vision imaging information, or other types of electronic imaging information. When light source 1 is multiple light sources, there are no limitations on the type of light source. For example, light source 1 includes a first light source and a second light source. In this case, the pupil expansion system also includes a light combining element located in the optical path between light source 1 and collimation system 2. The first and second light sources can be of the same or different types; the light source types include at least a point light source type and an image source type. The light combining element can be a semi-transparent, semi-reflective mirror.

[0042] There is no limitation on the collimation system 2 used, as long as it can convert the light beam emitted by the light source 1 into parallel light. For example, the collimation system 2 used is a single lens, a combination of lenses or a curved reflector 21. Figure 2 This is a schematic diagram of a pupil expansion system provided in the second embodiment of the present invention, as shown in FIG. Figure 2 As shown, the pupil expansion system includes a light source 1, a curved reflector 21, and a reflective grating 3. The light source 1 emits the image light information to be displayed. After emission, the light beam is collimated into parallel light by the curved reflector 21 and incident (it is worth noting that the incident angle here is an acute angle) on the reflective grating 3. After passing through the reflective grating 3, it is incident on the human eye 4 as parallel light. The reflective grating 3 can expand the exit pupil aperture. After the parallel light is emitted, it is incident on the human eye 4, and the human eye 4 obtains the image information. In this embodiment, the curved reflector 21 is used instead of the lens collimation system 2. The characteristics of the reflective grating 3 are utilized to make the incident light be emitted as parallel light. This further reduces the size of the system and simplifies the optical path of the system. In addition, the curved reflector 21 not only collimates the light but also corrects spherical aberration.

[0043] In order to achieve the best diffraction efficiency or a specific diffraction effect, in practice, the grating constant of the reflection grating 3 matches the wavelength of the light source 1. That is, the reflection grating 3 satisfies the corresponding grating equation to achieve the desired diffraction effect. According to the multi-slit diffraction theory, when the light wave is perpendicular to the grating, the position of the bright line in the diffraction pattern is determined by formula (1):

[0044] ; (1)

[0045] When the light wave is incident on the grating at an angle, the general expression of the grating equation is:

[0046] ; (2)

[0047] in, is an integer, is the grating constant, that is, the distance between two adjacent lines, is the angle of incidence, is the diffraction angle, is the wavelength of the light source.

[0048] In order to ensure that the light beam passing through the reflection grating 3 can enter the human eye, in practice, the reflection grating 3 is placed obliquely relative to the first parallel light, such as Figure 1 Specifically, the inclination angle of the reflection grating 3 relative to the first parallel light (as shown in FIG. Figure 1 The angle a) in the image is less than or equal to 45°. Since the reflective grating 3 is placed at a relatively small inclination angle, the volume occupied by the reflective grating 3 in the entire pupil expansion system is also correspondingly small, allowing the system to be compact and exquisite, resulting in a small size.

[0049] Figure 3 A schematic diagram of reflective grating diffraction provided in an embodiment of the present utility model. Figure 3 The grating equation is: . Figure 4 A schematic diagram of another reflective grating diffraction provided in an embodiment of the present utility model. Figure 4 The grating equation is: .

[0050] There is no limit on the incident angle of the first parallel light after being collimated by the collimation system 2 when it enters the reflection grating 3, and it is determined according to the actual situation. The incident angle φ of the first parallel light when it enters the reflection grating 3 satisfies the following conditions: the tangent value of the incident angle φ is the ratio of the preset beam diameter of the second parallel light to the beam diameter of the first parallel light; the angle between the first parallel light and the reflection grating 3 is 90°-φ. Specifically, the diameter of the beam can be obtained based on the exit pupil diameter of the light beam emitted by the light source 1 after passing through the collimation system 2. Figure 1It can be seen that the angle between the incident light and the reflection grating 3 and the light emitted from the reflection grating 3 is 90°. The angle between the incident light and the reflection grating 3 can be calculated based on the size of the pupil expansion required. The diameter of the light beam is designed according to the specific collimation system 2, assuming it is a; the diameter of the beam after expansion is b, then b / a is the tangent value of the incident angle; the incident angle can be calculated based on the inverse tangent , the angle between the incident light and the reflection grating 3 is 90°- .

[0051] After determining the angles of incident and outgoing light, the reflective grating 3 can be designed so that light incident at the desired incident angle passes through the reflective grating 3 and is emitted at the desired outgoing angle with maximum intensity, thereby achieving the purpose of pupil expansion.

[0052] After passing through the reflective grating 3, the image light information to be displayed, emitted by the light source 1, enters the human eye 4. To enable the human eye 4 to obtain an accurate image, in practice, the reflective grating 3 is selected as a one-dimensional reflective grating, which avoids changes in the image shape and improves the user experience when using the pupil expansion system.

[0053] When using the pupil expansion system, the information observed by the human eye 4 will be different depending on the light source 1 used.

[0054] When light source 1 is a single light source, the pupil expansion system is also called a single-light source pupil expansion system. Taking light source 1 as an image source, for example, light source 1 emits the image light information required by the user; collimation system 2 is used to collimate the image light information emitted by light source 1 into parallel light that is incident on reflective grating 3; reflective grating 3 is used to receive the incident image light information and emit it as parallel light, while also achieving pupil expansion; the human eye 4 receives the image light information after pupil expansion by reflective grating 3. To enable the user to see more information through the pupil expansion system, in addition to using light source 1 as a single light source, reflective grating 3 is also placed in the white light path. That is, the pupil expansion system is a dual-light pupil expansion system consisting of white light and a single light source. When a single light source is used as the image source, the human eye 4 can view the image light information while also seeing the real scene in the white light direct channel.

[0055] When multiple light sources 1 are used, the pupil expansion system is also referred to as a multi-light source pupil expansion system. For example, using a first light source and a second light source creates a dual-light system consisting of the first light source + the second light source. Furthermore, if multiple light sources 1 are used and a reflective grating 3 is placed in the white light path, a multi-light pupil expansion system consisting of white light + multiple light sources is formed. For example, a three-light fusion pupil expansion system consisting of white light + the first light source + the second light source is formed.

[0056] In practice, in order to improve the aiming accuracy of the pupil expansion system, the pupil expansion system further includes a hologram 5; the hologram 5 is located on the light-emitting side of the reflective grating 3. The hologram 5 can be placed at a distance from the reflective grating 3 (e.g. Figure 5 As shown in FIG, the reflective grating 3 may be attached to the reflective grating 3 by means of embossing, etching, masking, or exposure and development. In order to reduce the volume of the system, the reflective grating 3 may be attached to the reflective grating 3 by means of embossing, etching, masking, or exposure and development.

[0057] Figure 5 This is a schematic diagram of a pupil expansion system provided in the third embodiment of the present invention, as shown in FIG. Figure 5 As shown, the pupil expansion system includes a light source 1, a collimating element, a reflective grating 3 and a hologram 5. The light beam emitted by the light source 1 is collimated into parallel light by the collimating system 2 and incident on the reflective grating 3. After passing through the reflective grating 3, the light beam is incident on the hologram 5 as parallel light, and the human eye 4 obtains the division information recorded on the hologram 5.

[0058] Specifically, when the light source 1 used is a single light source, the pupil expansion system is also called a single light source pupil expansion system. Taking the light source 1 as an example, after the laser light source emits a light beam, the collimation system 2 collimates the light beam into parallel light and incidents it on the reflection grating 3. The reflection grating 3 receives the incident light beam, and the light beam is incident on the hologram 5 as parallel light after passing through the reflection grating 3. The human eye 4 obtains the division information recorded on the hologram 5. In order to enable the user to see more information through the pupil expansion system, on the basis of the light source 1 used being a single light source, the reflection grating 3 is also set on the white light path. That is, the pupil expansion system is a dual-light pupil expansion system consisting of white light + single light source. When the single light source used is a laser light source, the human eye 4 can see the division information recorded on the hologram 5 while also seeing the real scene of the white light direct channel.

[0059] When the light source 1 used is a multi-light source, the pupil expansion system is also called a multi-light source pupil expansion system. For example, a first light source and a second light source are used to form a dual-light system consisting of the first light source + the second light source. In addition, based on the light source 1 used being a multi-light source, a reflective grating 3 is also set on the white light path, forming a multi-light pupil expansion system consisting of white light + multiple light sources. For example, a three-light fusion pupil expansion system consisting of white light + the first light source + the second light source is formed. When the first light source is a laser light source and the second light source is an image source, the system can see the holographic grading information and the image source information while not blocking the white light direct channel. The real scene of the white light direct channel can also be seen.

[0060] In order to improve the imaging quality, in implementation, the pupil expansion system also includes an adjustment mechanism;

[0061] The adjustment mechanism is in contact with the reflection grating 3 and is used to change the placement angle of the reflection grating 3 .

[0062] The adjustment mechanism is not limited to any specific mechanism, as long as it allows for adjustment of the angle of the reflective grating 3. By rotating or tilting the adjustment mechanism, the angle of the reflective grating 3 relative to the incident light beam can be changed, thereby adjusting the direction of the diffracted light. Furthermore, once the reflective grating 3 is properly positioned using the adjustment mechanism, the mechanism typically includes a locking mechanism to maintain the grating's fixed position and prevent displacement due to vibration or other external factors.

[0063] Furthermore, in order to improve the imaging quality, in implementation, the pupil expansion system further includes an electro-optical modulator;

[0064] The electro-optic modulator is located between the light source 1 and the collimation system 2 and is used to adjust the phase distribution or amplitude of the light beam.

[0065] There is no limitation on the electro-optic modulator used, and the electro-optic modulator used may be a phase modulator or an amplitude modulator. The electro-optic modulator can dynamically adjust the phase distribution of the light beam to change the diffraction efficiency and diffraction angle of the grating, or dynamically adjust the phase or amplitude of the light beam by changing the voltage applied to the electro-optic modulator, thereby changing the diffraction characteristics of the grating.

[0066] The pupil expansion system provided by the embodiment of the present invention includes: a collimation system 2 and a reflective grating 3, which are sequentially arranged along the transmission direction of the light beam emitted by the light source 1. The light beam emitted by the light source 1 is collimated into parallel light by the collimation system 2, incident on the reflective grating 3, and then emitted as parallel light after passing through the reflective grating 3. In this pupil expansion system, the reflective grating 3 is used to expand the pupil of the light beam, allowing the user to observe image information over a wider range. Compared with the pupil expansion function achieved by using an optical waveguide, the use of the reflective grating 3 in the present invention eliminates the coupling-in and coupling-out process, reduces energy loss, improves energy utilization, and enhances the user experience when using a device containing a pupil expansion system. The curved reflector is used as the collimation system, and the characteristics of the reflective grating are utilized to make the incident light emit as parallel light, which further reduces the size of the system and simplifies the optical path of the system. A hologram is placed between the reflective grating and the human eye. After passing through the reflective grating and the hologram, the pupil of the light beam is expanded and the user can see the gradation information on the hologram, thereby improving the user experience when using the pupil expansion system.

[0067] A pupil dilation system is described above. This embodiment further provides a display device including the pupil dilation system. The display device including the pupil dilation system may be augmented reality (AR) glasses, etc.

[0068] The display device provided in this embodiment includes the pupil expansion system described above. The embodiment of the pupil expansion system has been described in detail above, and the embodiment of the pupil expansion system included in the display device will not be repeated here.

[0069] The display device provided in the present embodiment includes a pupil expansion system. The pupil expansion system comprises a collimation system 2 and a reflective grating 3, positioned sequentially along the transmission direction of a light beam emitted by a light source 1. The light beam emitted by the light source 1 is collimated by the collimation system 2 into parallel light, incident on the reflective grating 3, and then emitted as parallel light after passing through the reflective grating 3. In the pupil expansion system, the reflection grating 3 is used to expand the pupil of the light beam, so that the user can observe image information in a wider range; and compared with the function of expanding the pupil through an optical waveguide, the reflection grating 3 is used in the utility model, and there is no coupling-in and coupling-out process, which reduces energy loss, improves energy utilization, and improves the user's experience when using a device containing a pupil expansion system; a curved reflector is used as a collimation system, and the characteristics of the reflection grating 3 are used to make the incident light emerge in the form of parallel light, which further reduces the volume of the system and simplifies the optical path of the system; a hologram 5 is set between the reflection grating 3 and the human eye 4, and after passing through the reflection grating 3 and the hologram 5, the pupil of the light beam is expanded and the user can see the division information on the hologram; the display device containing the pupil expansion system can effectively increase the range of virtual images that the user can see, making it closer to the natural field of view of the human eye, and improving the user's experience when using the display device.

[0070] The above describes in detail the pupil expansion system and display device provided by the present invention. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between the various embodiments can be referred to in conjunction with each other. It should be noted that, for those skilled in the art, various improvements and modifications may be made to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the present invention.

[0071] It should also be noted that, in this specification, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

Claims

1. A pupil dilation system, characterized in that: include: A light source (1), a collimation system (2) and a reflection grating (3); The light source (1) is used to emit a light beam; The collimation system (2) and the reflection grating (3) are sequentially located in the transmission direction of the light beam emitted by the light source (1); The collimation system (2) is used to collimate the light beam emitted by the light source (1) to form a first parallel light, the first parallel light being incident on the reflection grating (3) and being reflected by the reflection grating (3) and then emitted as a second parallel light; wherein the reflection grating (3) is placed at an angle relative to the first parallel light.

2. The pupil expansion system according to claim 1, wherein: The inclination angle of the reflection grating (3) relative to the first parallel light is less than or equal to 45°.

3. The pupil expansion system according to claim 1, wherein: The incident angle φ of the first parallel light when incident on the reflection grating (3) satisfies the following conditions: the tangent value of the incident angle φ is the ratio of the preset beam aperture of the second parallel light to the beam aperture of the first parallel light; and the angle between the first parallel light and the reflection grating (3) is 90°-φ.

4. The pupil expansion system according to claim 1, wherein: The reflection grating (3) is a one-dimensional reflection grating.

5. The pupil expansion system according to claim 1, wherein: The grating constant of the reflection grating (3) matches the wavelength of the light source (1).

6. The pupil expansion system according to claim 1, wherein: The light source (1) includes a first light source and a second light source, and the pupil expansion system further includes: a light combining element; The light combining element is located on the light path between the light source (1) and the collimating system (2).

7. The pupil expansion system according to claim 6, wherein: The first light source and the second light source are of the same type or different types; wherein the light source types include at least a point light source type and an image source type.

8. The pupil expansion system according to claim 1, wherein: Also included are holographic sheets (5); The holographic plate (5) is located on the light-emitting side of the reflection grating (3).

9. The pupil expansion system according to claim 8, characterized in that The hologram (5) is attached to the reflective grating (3) by means of embossing, etching, masking or exposure and development.

10. The pupil expansion system according to any one of claims 1 to 9, characterized in that: The collimating system (2) is a single lens, a combined lens or a curved reflector (21).

11. The pupil expansion system according to claim 1, wherein: Also includes adjustment mechanism; The adjustment mechanism is in contact with the reflection grating (3) and is used to change the placement angle of the reflection grating (3).

12. The pupil expansion system according to claim 1, wherein: Also included are electro-optic modulators; The electro-optical modulator is located between the light source (1) and the collimation system (2) and is used to adjust the phase distribution or amplitude of the light beam.

13. A display device, characterized in that: A pupil dilation system comprising the method according to any one of claims 1 to 12.

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