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US-12625383-B2 - Optical module and head mounted display

US12625383B2US 12625383 B2US12625383 B2US 12625383B2US-12625383-B2

Abstract

Embodiments of the present disclosure provide an optical module and a head mounted display; wherein, the optical module comprises a first lens, a second lens, and a third lens provided sequentially, a beam splitter is provided between the second lens and the first lens, and a first phase retarder and a polarization reflection film provided on either side of the third lens. The first lens is configured for transmitting incident light and an optical path difference between an optical path at a 1.0 aperture of the first lens and a central optical path of the first lens is 0.25˜0.5 times of the central optical path.

Inventors

  • Chaiyuan SHI

Assignees

  • Goertek Optical Technology Co., Ltd.

Dates

Publication Date
20260512
Application Date
20220627
Priority Date
20220519

Claims (16)

  1. 1 . An optical module, comprising: a first lens, a second lens, and a third lens provided sequentially, a beam splitter, which is provided between the second lens and the first lens, and a first phase retarder and a polarization reflection film, provided on a side of the third lens, wherein, the first lens is configured for transmitting incident light, and an optical path difference between an optical path at a 1.0 aperture of the first lens and a central optical path of the first lens is 0.25˜0.5 times of the central optical path.
  2. 2 . The optical module according to claim 1 , wherein the optical path difference between the optical path at the 1.0 aperture of the first lens and the central optical path of the first lens is −1.6 to −1.
  3. 3 . The optical module according to claim 1 , wherein the optical path difference between the optical path at the 1.0 aperture of the first lens and the central optical path of the first lens is −1.58 to −1.2.
  4. 4 . The optical module according to claim 1 , wherein an optical path difference between an optical path at a 0.7 to 0.9 aperture of the first lens and the central optical path of the first lens is −1.5 to −0.05.
  5. 5 . The optical module according to claim 1 , wherein an optical path difference between an optical path at a 0.7 aperture of the first lens and the central optical path of the first lens is −1 to −0.05; an optical path difference between an optical path at a 0.8 aperture of the first lens and the central optical path of the first lens is −1.2 to −0.3; an optical path difference between an optical path at a 0.9 aperture of the first lens and the central optical path of the first lens is −1.5 to −0.5.
  6. 6 . The optical module according to claim 1 , wherein central thickness T 1 of the first lens is 3 mm<T 1 <6 mm; the first lens comprises a first surface and a second surface, both of which are aspherical surfaces.
  7. 7 . The optical module according to claim 6 , wherein the second lens comprises a third surface and a fourth surface, the third surface is adjacent to the second surface and is an aspherical surface, and the fourth surface is a flat surface or an aspherical surface; the third lens comprises a fifth surface and a sixth surface, both of which are aspherical surfaces, and the fifth surface is adjacent to the fourth surface.
  8. 8 . The optical module according to claim 7 , wherein the first phase retarder and the polarization reflection film are sequentially provided between the fourth surface and the fifth surface.
  9. 9 . The optical module according to claim 8 , wherein the optical module further comprises a polarizing film, which is provided between the fifth surface and the polarization reflection film.
  10. 10 . The optical module according to claim 9 , wherein the polarization reflection film and the polarizing film are stacked to form a film layer structure, which is attached to the fifth surface; the first phase retarder is attached to the fourth surface.
  11. 11 . The optical module according to claim 1 , wherein the first lens has a focal power φ 1 , which is positive and satisfies: 0<φ 1 <0.01.
  12. 12 . The optical module according to claim 1 , wherein the beam splitter has a reflectivity of 47% to 53%.
  13. 13 . The optical module according to claim 1 , wherein the first lens, the second lens, and the third lens have a refractive index n: 1.4<n<1.7; the first lens, the second lens, and the third lens have an Abbe number v: 20<v<75.
  14. 14 . The optical module according to claim 1 , wherein the optical module further comprises a display, which is configured for emitting circularly polarized light or linearly polarized light; when the display is adapted to emit the linearly polarized light, a second phase retarder is provided between the display and the first lens, and is configured for converting the linearly polarized light into circularly polarized light.
  15. 15 . The optical module according to claim 14 , wherein the display has a size of 1 inch to 2.1 inches.
  16. 16 . A head mounted display, comprising: a housing; and an optical module according to claim 1 .

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present disclosure is a National Stage of International Application No. PCT/CN2022/101436, filed on Jun. 27, 2022, which claims priority to a Chinese patent application No. 202210560045.9 filed with the CNIPA on May 19, 2022, both of which are hereby incorporated by reference in their entireties. TECHNICAL FIELD Embodiments of the present disclosure relate to the technical field of near-eye display imaging, and particularly to an optical module and a head mounted display. BACKGROUND In recent years, augmented reality (AR) and virtual reality (VR) technologies have been applied and rapidly developed in smart wearable devices, for example. Core components of both AR and VR technologies are optical modules. The quality of the display effect of the optical module directly determines the quality of the smart wearable device. In the prior art, to achieve a miniaturized and lightweight virtual reality imaging system, it is necessary to use smaller displays. However, under the same optical specifications (such as field of view angle, imaging quality, etc.), the smaller the size of the display, the more stringent the requirements become for the optical module. Most existing folded optical path solutions include two lenses. For small screens, the optical module must provide a large focal power and a significant bending angle for the peripheral field of view, which makes it difficult to achieve simultaneous clear imaging in both the central and peripheral fields of view. This also leads to a problem where field curvature is difficult to eliminate, thereby impacting the imaging effect. SUMMARY An objective of the present disclosure is to provide new technical solutions for an optical module and a head mounted display. In a first aspect, the present disclosure provides an optical module, which includes a first lens, a second lens, and a third lens provided sequentially; the first lens is configured for transmitting incident light;a beam splitter is provided between the second lens and the first lens;a first phase retarder and a polarization reflection film are provided on either side of the third lens;an optical path difference between an optical path at 1.0 aperture of the first lens and a central optical path of the first lens is 0.25˜0.5 times of the central optical path. Optionally, the optical path difference between the optical path at 1.0 aperture of the first lens and the central optical path of the first lens is −1.6 to −1. Optionally, the optical path difference between the optical path at 1.0 aperture of the first lens and the central optical path of the first lens is −1.58 to −1.2. Optionally, an optical path difference between an optical path at 0.7 to 0.9 aperture of the first lens and the central optical path of the first lens is −1.5 to −0.05. Optionally, an optical path difference between an optical path at 0.7 aperture of the first lens and the central optical path of the first lens is −1 to −0.05; an optical path difference between an optical path at 0.8 aperture of the first lens and the central optical path of the first lens is −1.2 to −0.3;an optical path difference between an optical path at 0.9 aperture of the first lens and the central optical path of the first lens is −1.5 to −0.5. Optionally, central thickness T1 of the first lens is 3 mm<T1<6 mm; the first lens includes a first surface and a second surface, both of which are aspherical surfaces. Optionally, the first lens has a focal power φ1, which is positive and satisfies: 0<φ1<0.01. Optionally, the second lens includes a third surface and a fourth surface, the third surface is adjacent to the second surface and is an aspherical surface, and the fourth surface is a flat surface or an aspherical surface; the third lens includes a fifth surface and a sixth surface, both of which are aspherical surfaces, and the fifth surface is adjacent to the fourth surface. Optionally, the first phase retarder and the polarization reflection film are sequentially provided between the fourth surface and the fifth surface. Optionally, the optical module further includes a polarizing film, which is provided between the fifth surface and the polarization reflection film. Optionally, the polarization reflection film and the polarizing film are stacked to form a film layer structure and are attached to the fifth surface; the first phase retarder is attached to the fourth surface. Optionally, the beam splitter has a reflectivity of 47% to 53%. Optionally, the first lens, the second lens, and the third lens have a refractive index n: 1.4<n<1.7; the first lens, the second lens, and the third lens have an Abbe number v: 20<v<75. Optionally, the optical module further includes a display, which is configured for emitting circularly polarized light or linearly polarized light; when the display emits the linearly polarized light, a second phase retarder is provided between the display and the first lens, and is configured for