TWM541014U - Penetration type eyepiece for near-eye display - Google Patents

Description

Penetrating eyepiece for near-eye displays

This creation is about the field of optical technology, especially a transmissive eyepiece for near-eye displays.

A near eye display (NED) or a head mounted display (HMD, or Head Wearable Display) is a display device worn on or around the head, some types of near-eye displays or headphones The display is equipped with a see-through eyepiece that superimposes the image of the display with the real scene of the outside world, in all aspects such as traffic (such as providing assistance in driving or flying) or entertainment. It has a large application space, and can also be applied to Augmented Reality (AR), existing transmissive near-eye display or head-mounted display, such as US2013070338A1, US2015177519A1 and other patents disclosed in the previous case, mainly By a microdisplay combined with a light guide component made of a transparent material such as glass or plastic, when the image (light) of the microdisplay is incident from an angle or surface of the light guiding member, The action or principle of optical reflection or the like allows the human eye to see or receive the image from another angle or surface of the light guiding member, and may also be The transparent light guiding member sees an external scene. However, in the conventional transparent near-eye display, the thickness of the light guiding member is from the side of the light guiding member facing the eye toward the light guiding member. One side of the external scene To calculate the thicker and smaller (Field of View, FOV, or Angle of View, AOV), not only the product is more cumbersome, but also the user is more difficult and inconvenient to receive the content information of the image.

In addition, some manufacturers use freeform optics to design the light guiding component. Although this technical solution can improve the viewing angle, it inevitably causes distortion or distortion of the image or external scene, although this Equal distortion can be compensated or improved by additional optical structure design, but it will increase the complexity and cost of the overall design, greatly reducing its practicality. Therefore, how to improve the above-mentioned defects, that is, the applicant's desire The technical difficulty of solving it lies.

In view of the above-mentioned lack of conventional transmissive near-eye displays, the purpose of this creation is to develop a transmissive eyepiece that can reduce thickness or increase viewing angle.

To achieve the above objective, the present invention provides a transmissive eyepiece for a near-eye display, comprising a first cymbal, a second cymbal and a portion of a reflective layer, wherein: the first cymbal is provided with an incident surface Receiving light from a display device into the first cymbal, the first cymbal is further provided with a planar first total internal reflection surface and a first joint surface; the second raft is provided with a second a joint surface, a planar second total internal reflection surface and a reflective surface, the reflective surface is plated with a reflective layer, the partially reflective layer is disposed on the second 稜鏡 second joint surface and the first 稜鏡Between the first joint faces, and the second jaw and the first jaw are joined to each other along the second joint surface and the first joint surface to form a complete penetrating eyepiece, and the first The total internal reflection surface and the second total internal reflection surface are parallel to each other and respectively located on opposite sides of the transmissive eyepiece, and the incident surface and the reflective surface are also respectively located on opposite sides of the transmissive eyepiece.

Wherein, the incident surface is curved or aspherical, and the incident surface is provided with two The element has a diffractive structure, and the reflecting surface is also curved or aspherical.

Wherein, the partially reflective layer is a beam splitter.

Wherein, the reflective layer is an aluminum layer or a silver layer.

Wherein, the inclination angle θ of the partially reflective layer satisfies the following condition: θ ≧ (θ _c + θ') /2, θ ' = arcsin (sin α / n), θ _c = arcsin (1/n), where θ _c For the critical angle of total reflection, α is a half angle of view and n is the refractive index of the second enthalpy.

In this way, the creation can increase the distance traveled by the light in the crucible, thereby effectively reducing the thickness of the transmissive eyepiece or increasing the viewing angle of the product, so that the user can more easily receive the content or message of the image, thereby enabling This creation can achieve better product performance and practicality.

[this creation]

3‧‧‧ first

31‧‧‧Incoming surface

32‧‧‧First total internal reflection surface

33‧‧‧First joint

4‧‧‧Second

41‧‧‧Second joint

42‧‧‧Second total internal reflection surface

43‧‧‧reflecting surface

44‧‧‧reflective layer

45‧‧‧Dip angle

5‧‧‧Partial reflection layer

6‧‧‧ display device

61‧‧‧Show light

62‧‧‧Show light

7‧‧‧ eyes

H‧‧‧thickness

The first figure is an exploded schematic view of one embodiment of the present creation.

The second figure is a combined schematic diagram of one embodiment of the present creation.

The third figure is a side cross-sectional view of one embodiment of the present creation.

The third A picture is a schematic diagram of the corresponding relationship between the half angle of view and the inclination of the partially reflective layer in one embodiment of the present creation.

The fourth figure is a schematic diagram of the action of one embodiment of the present creation.

Referring to the first, second and third figures, the present invention provides a transmissive eyepiece for a near-eye display, comprising a first 稜鏡3, a second 稜鏡4 and a part of the reflective layer. (partially reflective layer) 5, wherein: the material of the first 稜鏡3 and the second 稜鏡4 may be glass or optical grade plastic, in this embodiment, plastic is preferably used to have lightness. Quantitative advantage, the first 稜鏡3 is provided with a curved or aspherical input surface 31, and generally the binary diffraction structure can be engraved on the incident surface 31 (binary Diffractive optical elements (DOEs) are used to eliminate the chromatic aberration of magnification. However, the specific detail structure of the binary diffraction structure is a common knowledge in the technical field and is not the point of the present invention. Therefore, the drawing is not drawn and is not In detail, the incident surface 31 is configured to receive light from a display device 6 into the first buffer 3. The display device 6 may be a liquid crystal on silicon (LCoS) display or an organic light emitting diode. Polar body (OLED) display, In this embodiment, the display device 6 preferably adopts an organic light emitting diode display without a backlight module, thereby achieving the advantages of space saving. In addition, the first dome 3 is also provided with a planar shape (ie, a first flat internal reflection surface 32 and a first interface surface 33; the second crucible 4 is provided with a second joint surface 41 and a planar second surface a total internal reflection surface 42 and a curved or aspherical reflective surface 43. The reflective surface 43 is plated with a reflective layer 44 for forming a curved mirror, and more specifically, a concave mirror. (concave mirror), the reflective layer 44 may be an aluminum layer or a silver layer, and the partially reflective layer 5 is disposed on the second joint 4 and the second joint surface 41 and the first joint surface of the first crucible 3 Between 33, and the second 稜鏡4 and the first 稜鏡3 are joined to each other along the second joint surface 41 and the first joint surface 33 to constitute a complete penetrating eyepiece, and the first The total internal reflection surface 32 and the second total internal reflection surface 42 are parallel to each other and are respectively located at opposite sides of the transmissive eyepiece The incident surface 31 and the reflective surface 43 are also respectively located on opposite sides of the transmissive eyepiece. For example, in the first and second figures according to the embodiment, the first total internal reflection surface 32 and the second total internal reflection surface 42 are respectively located on the front and rear sides of the transmissive eyepiece, and the incident surface 31 and the reflection surface 43 are respectively located on the upper and lower sides of the transmissive eyepiece, wherein one can be It is noted that the second total internal reflection surface 42 is the side of the transmissive eyepiece facing the user's eyes, and the first total internal reflection surface 32 is the side of the transmissive eyepiece facing the external scene; wherein the portion The reflective layer 5 may specifically be a conventional beam splitter such as a non-polarized beam splitter or a polarized beam splitter (PBS); As shown in the figure of FIG. 3 and FIG. 3, in designing the transmissive eyepiece of the present invention, according to the optical principle, half of the angle of view that the user's eye 7 can see, that is, a half angle of view. Α- is the size of the display device 6 and the focal length of the penetrating eyepiece (foc As determined by al length), the half angle of view α is a known number, and at the same time, the angle of inclination 45 of the partially reflective layer 5 is between the partial reflection layer 5 and the second total internal reflection surface 42. The size of the angle θ is θ. Therefore, please continue to refer to the third A picture, if the light enters the second total internal reflection surface 42 of the second cymbal 4 from the incident angle of the half angle α. And generating refraction, and the angle of refraction is θ', and the refracted light passes through the reflection of the partially reflective layer 5 to generate total internal reflection on the second total internal reflection surface 42, according to geometric principles. It can be calculated that the incident angle when the light generates total internal reflection on the second total internal reflection surface 42 is 2θ-θ', and it is known that 2θ-θ' must be greater than or equal to the critical angle θ _{c of} total reflection, and thus, the portion The size θ of the angle of inclination 45 of the reflective layer 5 is designed to satisfy the following condition: θ ≧ (θ _c + θ ') / 2, where θ ' is the refraction generated when light enters the second total internal reflection surface 42 from air. angle, θ _c is the critical angle of total reflection, further, by Cornell Law Division (Snell's Law), rectifiable θ '= arcsin (sin α / n), θ c = arcsin (1 / n), where n is the index of refraction (refractive index) of the second Prism 4, seen from the creation of this structure, as long as the above conditions in compliance with The smaller the inclination angle 45 is used, the thickness of the transmissive eyepiece can be reduced according to the design disclosed by the prior art patents; if compared with the thickness of the design disclosed in the prior patent, this Creation will give you a bigger perspective.

The working principle of the creation is explained below: Please refer to the fourth figure. With the above structure, the creation only needs to tilt the display device 6 to a certain angle so as not to be the first total internal reflection of the first 稜鏡3. The surface 32 is parallel, and the display light 61 generated by the display device 6 can be easily entered from the incident surface 31 of the first crucible 3 into the first crucible 3, and the first total internal reflection surface 32 is The total reflection is generated, and then the display ray 61 passes through the partially reflective layer 5 and generates total reflection on the second total internal reflection surface 42 of the second cymbal 4, and then the display ray 61 is The reflective surface 43 and the reflective mirror 44 form a reflection on the concave mirror while being amplified, so that the enlarged display light 62 passes through the total reflection of the second total internal reflection surface 42 and the partially reflective layer. The reflection of 5 finally reaches the user's eye 7, so that the user can see the image of the display device 6, and the user can also see the external scene through the creation.

Continuing to refer to the first and fourth figures, the creation structure is simple, which can facilitate mass production, and by appropriately arranging the inclination angle 45, the total reflection principle can be used to display the image of the display device 6, thereby Compared with the conventional penetrating eyepiece, the creation can effectively reduce the thickness H of the penetrating eyepiece under the premise of having the same angle of view (FOV or AOV); or, under the premise of having the same thickness, the creation A larger viewing angle can be achieved, making it easier for users to receive image content or messages, which in turn allows for better product performance and usability.

3‧‧‧ first

31‧‧‧Incoming surface

4‧‧‧Second

43‧‧‧reflecting surface

44‧‧‧reflective layer

5‧‧‧Partial reflection layer

6‧‧‧ display device

Claims (5)

A transmissive eyepiece for a near-eye display, comprising a first cymbal, a second cymbal and a portion of a reflective layer, wherein: the first cymbal is provided with an incident surface for receiving light from a display device Entering the first weir, the first weir is further provided with a planar first total internal reflection surface and a first joint surface; the second weir is provided with a second joint surface and a planar second full An inner reflective surface and a reflective surface, the reflective surface is plated with a reflective layer disposed between the second joint surface of the second weir and the first joint surface of the first weir, and The second and the first sides are joined to each other along the second joint surface and the first joint surface to form a complete penetrating eyepiece, and the first total internal reflection surface and the second total internal reflection The faces are parallel to each other and are respectively located on opposite sides of the transmissive eyepiece, and the incident surface and the reflecting surface are also respectively located on opposite sides of the transmissive eyepiece. The transmissive eyepiece for a near-eye display according to claim 1, wherein the incident surface is curved or aspherical, and the incident surface is provided with a binary diffraction structure, and the reflective surface is also Curved or aspherical. The transmissive eyepiece for a near-eye display according to claim 1, wherein the partially reflective layer is a beam splitter. The transmissive eyepiece for a near-eye display according to claim 1, wherein the reflective layer is an aluminum layer or a silver layer. The transmissive eyepiece for a near-eye display according to claim 1, wherein the inclination angle θ of the partially reflective layer satisfies the following condition: θ≧(θ _c +θ')/2, θ'=arcsin( Sin α/n), θ _c =arcsin(1/n), where θ _c is the critical angle of total reflection, α is the half angle of view, and n is the refractive index of the second 稜鏡.