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Optical module, near-to-eye display device and light projection method

An optical module and beam technology, applied in the optical field, can solve the problems of light leakage, affect the user's viewing experience, affect the user experience, etc., and achieve the effect of reducing light leakage, improving the feeling effect, and eliminating light leakage.

Pending Publication Date: 2021-04-09
SHANGHAI UROPTICS CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] But in the current pancake solution, the light incident on the user's eyes, in addition to the light expected by the user, also has some undesired light, which affects the user experience
Especially when the incident angle of light is large, when the incident light passes through the reflective polarizer for the first time, it may not be completely reflected, but a large proportion of light leakage will occur, and part of the light will still pass through the reflective polarizer. Into the user's eyes, the intensity of light leakage may reach 38% of the signal light intensity along the optical axis, thereby affecting the user's viewing experience

Method used

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  • Optical module, near-to-eye display device and light projection method
  • Optical module, near-to-eye display device and light projection method
  • Optical module, near-to-eye display device and light projection method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0096] The optical path structure of embodiment 1 is as Figure 7 As shown, there is a light-emitting screen upstream of the optical path of the absorbing polarizer Pol. The specific parameters of the light path structure of embodiment 1 are as follows:

[0097] The light transmission axis of the absorbing polarizer Pol is parallel to the x-axis; the first phase retardation unit QWP1 is a positive phase retardation unit, which consists of n o e And the optical axis satisfies α 1 =45 ° of quarter-wave plate constitutes; the transmittance of the semi-transparent and semi-reflective layer BS is 50%, and the reflectivity is 50%; the second phase delay unit QWP2 is a positive phase delay unit, and it consists of n o e And the optical axis satisfies α 2 = α 1 =45° quarter-wave plate; the transmission axis of the polarizing beam splitter PBS is parallel to the y-axis.

[0098] For the convenience of illustration, the polarization state of light during propagation is represented ...

Embodiment 2

[0106] Embodiment 2 has the same optical path structure as Embodiment 1, but wherein the first phase delay unit is a positive phase delay unit, the second phase delay unit is a negative phase delay unit, and the second phase delay unit consists of n o >n e And the optical axis satisfies α 2 =-α 1 =-45° (ie 135°) quarter-wave plate constitutes.

[0107] Different from Example 1, in Example 2, when the light is at θ=60°, When incident, the rotation axis composed of the fast axis and the slow axis of the second phase delay unit QWP2, that is, the red straight line F N S N with F O S O Coincident (point FN coincides with point SN, point F0 coincides with point S0, compare Figure 9A with 8A ).

[0108] Therefore, in light at θ=60°, When it is incident, the point O and the point M modulated by the first phase delay unit QWP1 and the second phase delay unit QWP2 after passing through the polarizer Pol coincide with the point M, and this point and point P are exactly symm...

Embodiment 3

[0111] Compared with Embodiment 1, the optical path structure of Embodiment 3 has the following difference: a first phase compensation unit RA is added. The optical path structure of embodiment 3 is as Figure 10 shown.

[0112] The second phase delay unit is a negative phase delay unit, which consists of n o >n e And the optical axis satisfies α 2 =-α 1 =-45° quarter-wave plate. The first phase delay unit is a positive phase delay unit.

[0113] The first phase compensation RA can have various configurations. The parameters of the first phase compensation unit RA selected in this embodiment are shown in the table below, which includes the phase retarder A1 and the phase retarder A2 stacked along the direction of the optical path. Wherein the parameters of the phase retarder A1 are as follows: n o e , the optical axis is parallel to the x-axis, and the phase retardation is 100nm. The parameters of phase retarder A2 are as follows: n o >n e , the optical axis is para...

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Abstract

The invention provides an optical module. The optical module sequentially comprises a first phase delay unit, a semi-transparent and semi-reflective layer, a second phase delay unit and a polarizing beam splitter, the first phase delay unit and the second phase delay unit are both positive phase delay units or negative phase delay units and meet the following relationship: alpha1 = alpha2 = 45 DEG or 135 DEG; or the first phase delay unit and the second phase delay unit are positive phase delay units or negative phase delay units with opposite types and meet the following relationship: alpha1 = -alpha2 = 45 DEG or 135 DEG, wherein alpha1 is the angle rotated by the optical axis of the first phase delay unit when the polarization direction of the linearly polarized light incident on the first phase delay unit is rotated anticlockwise when the linearly polarized light is in normal incidence when being observed against the direction of the optical path, and alpha2 is an angle through which the light transmission axis of the polarizing beam splitter rotates anticlockwise to the optical axis of the second phase delay unit when being observed against the direction of the optical path. By means of the optical module, light leakage in the folded light path can be reduced, particularly, light leakage in the folded light path can be reduced or eliminated in a large-angle range according to some preferred embodiments, and the feeling effect of a user can be improved.

Description

technical field [0001] The present invention generally relates to the field of optics, and in particular to an optical module, a near-eye display device and a light projection method. Background technique [0002] In virtual display (VR), augmented display (AR), and other hybrid display technologies, optical modules are required to present images to users. Existing optical modules are generally large in size, and the thickness is often above 30mm. With the advancement of technology, users pay more and more attention to the size and weight of the product. Therefore, it is necessary to develop a small and light product to meet the market demand. demand. Among them, the most limited factor is the optical module. In order to solve the above volume and weight problems, many companies have launched VR or AR solutions based on pancake technology solutions, that is, optical modules based on folded optical paths. [0003] In this optical module with folded optical path, it mainly ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B27/01G02B27/28
CPCG02B27/0172G02B27/283G02B27/286
Inventor 梁乾亿吴皓王天寅杨兴朋
Owner SHANGHAI UROPTICS CO LTD