Wearable optical system

Abstract

The utility model belongs to the field of optical display, and particularly relates to a wearable optical system, which comprises a light source for emitting light; the prism group comprises a first prism and a second prism; light rays emitted by the light source pass through the prism group and the beam splitting film to form a first image and a second image, the first image is formed by a first focal plane light path, and the light source is emitted to an exit pupil position after being sequentially transmitted, reflected and transmitted on the first surface, the second surface and the third surface of the first prism and then reflected by the beam splitting film and transmitted by the second surface; the light source is transmitted, reflected and transmitted on the first surface, the second surface and the third surface of the first prism in sequence and then is emitted to the exit pupil position after being transmitted by the light splitting film, reflected by the rear surface, transmitted by the light splitting film and transmitted by the second surface, and the focal plane depths of the first image and the second image are different. Thus, a compact and portable wearable optical system is formed.

Description

Technical Field

[0001] The utility model belongs to the field of optical display, and specifically relates to a wearable optical system. Background Art

[0002] For wearable optical systems, since they are worn by viewers, the volume and weight of the entire optical system will affect the viewer's experience. Therefore, keeping the entire system light and thin is a property that wearable optical systems need to maintain.

[0003] In addition, if a defocused image is formed in a wearable optical system, that is, at least two focal planes are formed, the corresponding optical system usually needs to be configured with two image sources, which makes the structure complicated, the space utilization rate is low, the system is complex, and the required cost increases accordingly. Utility Model Content

[0004] The present invention is proposed based on the above-mentioned requirements of the prior art, and the technical problem to be solved by the present invention is to provide a wearable optical system to improve the viewing experience of the viewer.

[0005] In order to solve the above problems, the technical solution provided by the utility model includes:

[0006] Provided is a wearable optical system, comprising a light source, emitting light; a prism group, the prism group comprising a first prism and a second prism; the first prism comprising three surfaces, wherein the first surface is arranged opposite to the light source, and the light emitted by the light source can be incident on the first surface; the second surface is arranged opposite to the first surface, and the light transmitted through the first surface can be incident on the second surface; the third surface is arranged opposite to the second surface, and the light reflected through the second surface can be incident on the third surface; the second prism comprises a front surface and a rear surface, the front surface is adapted to the third surface, and a dichroic film is arranged between the front surface and the third surface; the rear surface is arranged opposite to the front surface, and a reflective film is plated on the rear surface, so that the light transmitted through the front surface can be incident on the rear surface, and the light reflected through the rear surface can be incident on the rear surface.

[0007] The emitted light can be incident on the front surface; the light emitted by the light source is emitted to the exit pupil position after propagation to form a first image and a second image, the first image is formed by the first focal plane light path: the light source is transmitted, reflected and transmitted on the first, second and third surfaces of the first prism in sequence, and then is emitted to the exit pupil position after reflection from the dichroic film and transmission from the second surface; the second image is formed by the second focal plane light path: the light source is transmitted, reflected and transmitted on the first, second and third surfaces of the first prism in sequence, and then is emitted to the exit pupil position after transmission from the dichroic film, reflection from the rear surface, transmission from the dichroic film and transmission from the second surface, and the first image and the second image have different focal plane depths.

[0008] Through the above arrangement, the wearable optical system can still form two focal planes with different focal plane depths, namely the first image and the second image, under the premise that only one light source is provided. This arrangement can effectively reduce the complexity of the optical system and reduce the production cost. In addition, this structure uses fewer optical elements, making the overall structure light and simple, and effectively improving the viewer's experience. The third surface and the front surface are clamped with a dichroic film to ensure that the optical system is compact and light.

[0009] Preferably, in the first focal plane light path and the second focal plane light path, when the light passes through the first surface and is incident on the second surface, the incident angle is greater than the total internal reflection angle of the first prism: arcsin (1 / n), where n is the refractive index of the material of the first prism.

[0010] The above arrangement enables optical reflection to be achieved without adding any optical film group, thereby effectively simplifying the structure of the optical system, thereby maintaining the overall lightness and stability.

[0011] Preferably, in the first focal plane light path, when the light is reflected by the dichroic film and incident on the second surface, the incident angle is smaller than the total internal reflection angle of the first prism.

[0012] Through the above arrangement, the light reflected by the dichroic film can be emitted to the exit pupil position through the second surface, so that the first image can be presented at the exit pupil position.

[0013] Preferably, the rear surface is coated with a total reflection film, and in the second focal plane light path, the light is incident on the second surface after being reflected by the rear surface and transmitted by the beam splitter film, and the incident angle is smaller than the total internal reflection angle of the first prism.

[0014] Through the above arrangement, light passes through the second surface to form a second image at the exit pupil position.

[0015] Preferably, at least one of the first surface, the second surface, the third surface and the rear surface is a free-form surface.

[0016] Preferably, the surfaces of the first surface, the second surface, the third surface and the rear surface are all free-form surfaces.

[0017] The above arrangement is used to correct off-axis aberrations, thereby ensuring the presentation of the first image and the second image.

[0018] Preferably, the exit pupil center is taken as the origin, the vertical upward direction in the exit pupil plane is taken as the positive direction of the Y axis, the direction of the exit pupil plane perpendicular to the vertical direction and facing forward is taken as the positive direction of the X axis, the direction perpendicular to the XOY plane toward the wearable optical system is taken as the positive direction of the Z axis, the distance between the center of the second surface and the exit pupil center is in the range of 13 mm to 19 mm, the Y eccentricity range of the second surface is ±2 mm, and the acute angle range between the second surface and the XOY plane is 0° to 12°.

[0019] Preferably, the Z eccentricity range of the center of the third surface is 17 mm to 23 mm, the Y eccentricity range is -3 mm to +1 mm, and the acute angle range with the XOY plane is 18° to 25°.

[0020] Preferably, the Z eccentricity range of the center of the first surface is 16 mm to 23 mm, the Y eccentricity range is 7 mm to 13 mm, and the acute angle range with the XOY plane is 55° to 65°.

[0021] Preferably, the Z eccentricity range of the center of the light-emitting surface of the light source is 19mm~25mm, the Y eccentricity range is 12mm~19mm, and the Y eccentricity value of the center of the light-emitting surface of the light source is greater than the Y eccentricity value of the center of the first surface; the acute angle range between the light-emitting surface of the light source and the XOY plane is 55°~65°.

[0022] The above arrangement defines the relative positional relationship between the various optical elements, thereby ensuring stable and normal imaging.

[0023] Compared with the prior art, the present invention reduces the volume of the wearable optical system as much as possible through the relative position relationship of the above-mentioned optical elements and the optical properties of the optical elements. In addition, the optical system formed by the present invention can meet the requirement that when only one light source is set in the system, two different focal planes with different focal plane depths can still be formed at the exit pupil, that is, the first image and the second image are formed. In addition, through the relative arrangement relationship of the first prism, the second prism and the dichroic film, the entire optical system is compact and thin, which helps to improve the viewer's experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of this specification 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 recorded in the embodiments of this specification. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0025] Figure 1 A relative position structure diagram of a wearable optical system in an embodiment of the utility model;

[0026] Figure 2 A schematic diagram of an optical path of a wearable optical system in an embodiment of the utility model;

[0027] Figure 3 A schematic diagram of the optical path for forming the first image and the second image in an embodiment of the present utility model;

[0028] Figure 4 This is a schematic diagram of the optical path of the first focal plane in an embodiment of the utility model;

[0029] Figure 5 This is a schematic diagram of the optical path of the second focal plane in the embodiment of the utility model;

[0030] Figure 6 A schematic diagram of a coordinate system of a wearable optical system in an embodiment of the present utility model;

[0031] Figure 7 This is a structural schematic diagram of a feasible implementation method in the embodiment of the utility model;

[0032] Figure 8 The sampling field MTF curve of the first image in a feasible implementation manner in the embodiment of the utility model;

[0033] Fig. 9 The sampling field MTF curve of the second image in a feasible implementation manner in the embodiment of the utility model;

[0034] Fig.10 A comparison diagram of the distortion grid of the first image and the ideal focal plane in a feasible implementation manner in an embodiment of the utility model;

[0035] Fig.11 It is a comparison diagram of the distortion grid of the second image and the ideal focal plane in a feasible implementation manner in the embodiment of the utility model.

[0036] Reference numerals:

[0037] 1. Exit pupil; 2. Second surface; 3. Third surface; 4. Back surface; 5. First surface; 6. Protective glass; 7. Light source surface; 8. Front surface; 9. First image; 10. Second image; 11. First prism; 12. Second prism. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] In the description of the embodiments of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the term "connected" should be understood in a broad sense, for example, it can be a fixed connection, or a detachable connection, or an integral connection can be a mechanical connection, or an electrical connection can be a direct connection, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0040] The terms "top", "bottom", "above", "lower", and "on" used throughout the description are relative to the relative positions of components of a device, such as the relative positions of the top and bottom substrates within a device. It is understood that devices are multifunctional regardless of their orientation in space.

[0041] To facilitate understanding of the embodiments of the present application, further explanation will be given below with reference to specific embodiments in conjunction with the accompanying drawings. The embodiments do not constitute a limitation on the embodiments of the present application.

[0042] This embodiment provides a wearable optical system, such as Figure 1-Figure 11 shown.

[0043] The wearable optical system includes a light source and a prism group.

[0044] The light source is used to provide the light required by the wearable optical system. Further, the light source is a flat panel display, and the flat panel display includes a protective glass 6, and the light emitted by the image source passes through the protective glass 6 and is incident on the prism group.

[0045] The prism group includes a first prism 11 and a second prism 12.

[0046] The first prism 11 is disposed opposite to the light source. The first prism 11 includes a first surface 5 , a second surface 2 and a third surface 3 .

[0047] The first surface 5 is arranged opposite to the light source, and the light emitted by the light source passes through the first surface 5 in a transmission form.

[0048] The second surface 2 is arranged opposite to the first surface 5. Thus, the light emitted from the first surface 5 is incident on the second surface 2, and the angle at which the incident light enters the second surface 2 is greater than the total internal reflection angle arcsin(1 / n), where n is the refractive index of the material of the first prism 11. Based on the above arrangement, the light will continue to propagate in the form of reflection after being incident on the second surface 2.

[0049] The third surface 3 is arranged opposite to the second surface 2. The light reflected by the second surface 2 is incident on the third surface 3. The third surface 3 is coated with a dichroic film, which can split the light incident thereon into two paths, including a light path for reflecting the incident light and a light path for transmitting the incident light. The specific ratio of the amount of reflected light to the amount of incident light is determined by the splitting ratio. When the splitting ratio of the dichroic film is 1:1, among the light incident on the plane dichroic mirror, 50% of the light will be emitted in the form of transmission, and the remaining 50% of the light will be emitted in the form of reflection.

[0050] After the light from the light source is incident on the first surface 5, it continues to propagate in the form of transmission, propagates to the second surface 2, is output in the form of reflection, and is incident on the third surface 3. After being reflected by the dichroic film, it is emitted again to the position of the second surface 2. The light incident on the second surface 2 changes due to the incident angle, so that the incident angle on the second surface is less than the total internal reflection angle, so that after the light passes, it will be emitted to the position of the exit pupil 1 in the form of transmission to form a first image 9, and finally enter the viewer's eyes. The above light path is the first focal plane light path.

[0051] The wearable optical system also includes a second focal plane optical path, specifically including: the light emitted by the light source continues to propagate in the form of transmission after being incident on the first surface 5, propagates to the second surface 2, and is output in the form of reflection, and is incident on the third surface 3, continues to propagate through the transmission of the dichroic film, and is output to the second prism 12 arranged opposite to the first prism 11, and is emitted to the second surface 2 again under the intervention of the second prism 12. The light incident on the second surface 2 changes due to the incident angle, so that the incident angle on the second surface is less than the total internal reflection angle, so that the light will be emitted to the position of the exit pupil 1 in the form of transmission after passing through to form a second image 10, and finally enter the viewer's eyes. Compared with the first focal plane optical path, the second focal plane optical path is more processed by the second prism 12, so the focal length of the second focal plane optical path is less than the focal length of the second focal plane optical path, that is, the focal plane depth of the second image 10 is different from the focal plane depth of the first image 9.

[0052] The second prism 12 includes a front surface 8 and a rear surface 4. The front surface 8 is a side of the second prism 12 that is relatively close to the first prism 11, and the rear surface 4 is a side of the second prism 12 that is relatively far from the first prism 11. The front surface 8 is arranged opposite to the rear surface 4. The front surface 8 and the rear surface 4 have the same shape, or have a similar shape. In order to reduce processing costs, the front surface 8 and the rear surface 4 have surfaces of the same shape.

[0053] The front surface 8 is arranged opposite to the third surface 3, and the front surface 8 is adapted to the third surface 3. Further, the front surface 8 and the third surface 3 are bonded to form a whole, and the first prism 11 and the second prism 12 are connected to the third surface 3, the diaphragm and the front surface 8 in sequence. The light transmitted through the diaphragm will enter the second prism 12 through the front surface 8.

[0054] The rear surface 4 is plated with a total reflection film.

[0055] The partial second focal plane optical path formed under the influence of the second prism 12 includes: the light entering the second prism 12 from the front surface 8 is incident on the rear surface 4, and is reflected toward the front surface 8 again through the total reflection film on the rear surface 4, and the reflected light is transmitted through the front surface 8, the dichroic film, the third surface 3 and the second surface 2 in sequence, and is emitted toward the exit pupil 1 to form a second image 10, which is finally received by the viewer's eyes.

[0056] In addition, the first surface 5, the second surface 2 and the third surface 3 in the first prism 11 and the front surface 8 and the rear surface 4 in the second prism 12 (since the third surface 3 and the front surface 8 are glued together, there are actually four surfaces), at least one free-form surface is included. Preferably, in order to correct off-axis aberrations, all of the above surfaces are free surfaces. Furthermore, in order to reduce the manufacturing difficulty of the entire wearable optical system, the material of the first prism 11 and the second prism 12 can be selected from moldable low-melting-point glass or injection-molded optical resin material.

[0057] Observed from the position of the exit pupil 1 of the wearable optical system, the diagonal fields of view displayed by the first image 9 and the second image 10 are not less than 35°, wherein the horizontal field angle is at least 30°. The diameter of the exit pupil 1 of the wearable optical system is at least greater than 7 mm.

[0058] In order to better describe the relative positional relationship between the various optical devices and the various optical surfaces in the wearable optical system, a reference coordinate system is established, such as Figure 6 shown.

[0059] Taking the center of exit pupil 1 as the origin, the direction toward the wearable optical system based on the position of exit pupil 1 is the Z axis, the upward direction perpendicular to the Z axis is the Y axis, and the direction perpendicular to the YOZ plane is the X axis.

[0060] The Z eccentricity range of the center of the first surface 5 is 16 mm to 23 mm, the Y eccentricity range is 7 mm to 13 mm, and the acute angle range with the XOY plane is 55° to 65°.

[0061] The distance between the second surface 2 and the center of the exit pupil 1 ranges from 13 mm to 19 mm; the Y eccentricity range of the center of the second surface 2 is ±2 mm, and the acute angle (Alpha angle) with the XOY plane ranges from 0° to 12°.

[0062] The Z eccentricity range of the center of the third surface is 17 mm to 23 mm, the Y eccentricity range is -3 mm to +1 mm, and the acute angle range with the XOY plane is 18° to 25°.

[0063] The Z eccentricity range of the center of the rear surface 4 is 17 mm to 23 mm, the Y eccentricity range is -3 mm to +1 mm, and the acute angle range with the XOY plane is 18° to 25°.

[0064] The Z eccentricity range of the center of the light emitting surface of the light source is 19mm~25mm, the Y eccentricity range is 12mm~19mm, and the Y eccentricity value of the center of the light emitting surface 7 of the light source is greater than the Y eccentricity value of the center of the first surface 5; the acute angle range between the light emitting surface 7 of the light source and the XOY plane is 55°~65°.

[0065] The focal depth of the first image 9 is in the range of 500 mm to 100000 mm, and the focal depth of the second image 10 is in the range of -100000 mm to -500 mm. The focal length of the first prism 11 is in the range of 12 mm to 20 mm.

[0066] A feasible implementation method of this embodiment is given below. Figure 7 As shown, a wearable optical system is formed based on the optical parameters involved in Tables 1 to 3, wherein the field of view of the wearable optical system is 35°, the diameter of the exit pupil 1 is 7 mm, the depth of the first focal plane is -5000 mm, and the focal length is 15.72 mm. The depth of the second focal plane is -1000 mm, and the focal length is 15.67 mm.

[0067] Table 1 Optical system parameters of the first focal plane optical path

[0068]

[0069]

[0070] Table 2 Optical system parameters of the second focal plane optical path

[0071]

[0072] Among the above surfaces, the free-form surface satisfies the equation: c is the inverse of the radius of curvature, r is the radial distance of a point on the surface, k is the quadratic constant, C i are the coefficients of the higher-order terms.

[0073] Table 3 Free surface coefficients

[0074]

[0075] Based on the above wearable optical system, Figure 8 and Fig. 9 As shown in the figure, the MTF curves of the sampling fields of the first image 9 and the second image 10, namely Modulation Transfer Function, are the term in optical engineering and are often used to evaluate the performance of optical systems. The horizontal axis represents the sampling frequency of the image space, the vertical axis represents the contrast, F1 to F9 are the sampling fields used to evaluate the display quality of the system, and X and Y represent two directions respectively. The MTF values ​​of each field of view at 30lp / mm are higher than 0.1, indicating that the imaging of the above system is excellent. Fig.10 and Fig.11 As shown, the distortion grids of the focal planes where the first image 9 and the second image 10 are located are compared with the ideal focal plane, and the optical distortion of the wearable optical system is less than 7%. That is, the optical system formed by the above embodiment has a relatively stable performance and can ensure the imaging quality.

[0076] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above description is only the specific implementation method of the present application and is not intended to limit the scope of protection of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A wearable optical system, characterized in that: include: Light source, emitting light; A prism group, the prism group comprising a first prism and a second prism; A first prism includes three surfaces, wherein the first surface is arranged opposite to the light source, and the light emitted by the light source can be incident on the first surface; the second surface is arranged opposite to the first surface, and the light transmitted through the first surface can be incident on the second surface; the third surface is arranged opposite to the second surface, and the light reflected through the second surface can be incident on the third surface; The second prism comprises a front surface and a rear surface, wherein the front surface is matched with the third surface, and a beam splitter film is arranged between the front surface and the third surface; the rear surface and the front surface are arranged opposite to each other, and a reflective film is coated on the rear surface, so that light transmitted through the front surface can be incident on the rear surface, and light reflected through the rear surface can be incident on the front surface; The light emitted by the light source is emitted toward the exit pupil position after propagation to form a first image and a second image. The first image is formed by a first focal plane optical path: the light source is sequentially transmitted, reflected, and transmitted on the first, second, and third surfaces of the first prism, and then is reflected by the dichroic film and transmitted by the second surface before being emitted toward the exit pupil position; the second image is formed by a second focal plane optical path: the light source is sequentially transmitted, reflected, and transmitted on the first, second, and third surfaces of the first prism, and then is transmitted by the dichroic film, reflected on the rear surface, transmitted by the dichroic film, and transmitted by the second surface before being emitted toward the exit pupil position. The focal plane depths of the first image and the second image are different.

2. The wearable optical system according to claim 1, characterized in that: In the first focal plane optical path and the second focal plane optical path, when light passes through the first surface and is incident on the second surface, the incident angle is greater than the total internal reflection angle of the first prism: arcsin (1 / n), where n is the refractive index of the material of the first prism.

3. The wearable optical system according to claim 1, characterized in that: In the first focal plane light path, when the light is reflected by the beam splitter film and incident on the second surface, the incident angle is smaller than the total internal reflection angle of the first prism.

4. The wearable optical system according to claim 1, characterized in that: The rear surface is coated with a total reflection film. In the second focal plane light path, the light is incident on the second surface after being reflected by the rear surface and transmitted by the beam splitter film, and the incident angle is smaller than the total internal reflection angle of the first prism.

5. The wearable optical system according to claim 1, characterized in that: At least one of the first surface, the second surface, the third surface and the rear surface is a free-form surface.

6. The wearable optical system according to claim 5, characterized in that: The surfaces of the first surface, the second surface, the third surface and the rear surface are all free-form surfaces.

7. The wearable optical system according to claim 1, characterized in that: Taking the exit pupil center as the origin, the vertical upward direction in the exit pupil plane as the positive direction of the Y axis, the direction of the exit pupil plane perpendicular to the vertical direction and facing forward as the positive direction of the X axis, and the direction perpendicular to the XOY plane toward the wearable optical system as the positive direction of the Z axis, the distance between the center of the second surface and the exit pupil center ranges from 13 mm to 19 mm, the Y eccentricity range of the second surface is ±2 mm, and the acute angle range between the second surface and the XOY plane is 0° to 12°.

8. The wearable optical system according to claim 7, characterized in that: The Z eccentricity range of the center of the third surface is 17 mm to 23 mm, the Y eccentricity range is -3 mm to +1 mm, and the acute angle range with the XOY plane is 18° to 25°.

9. The wearable optical system according to claim 8, characterized in that: The center of the first surface has a Z eccentricity range of 16 mm to 23 mm, a Y eccentricity range of 7 mm to 13 mm, and an acute angle range with the XOY plane of 55° to 65°.

10. The wearable optical system according to claim 9, characterized in that: The Z eccentricity range of the center of the light emitting surface of the light source is 19mm~25mm, the Y eccentricity range is 12mm~19mm, and the Y eccentricity value of the center of the light emitting surface of the light source is greater than the Y eccentricity value of the center of the first surface; the acute angle range between the light emitting surface of the light source and the XOY plane is 55°~65°.

Images