TWI745210B - Optical module - Google Patents

Abstract

The present invention provides an optical module defined a display side and an eye side. The optical module includes: a first lens unit located on the eye side; a second lens unit located on the display side; and a transparent display unit provided between the first lens unit and the second lens unit. The user's eyes can see the augmented reality virtual image on the display side formed by the transparent display unit and the image of the environment background simultaneously by the optical module of the present invention.

Description

Optical module

The invention relates to an optical module, in particular to an optical module that can be used in an augmented reality device for near-eye display.

In recent years, the development of near-eye display devices such as virtual reality and augmented reality has been booming. At present, two systems, non-direct-view type and direct-view type, have been developed. The non-direct-view type mostly uses beam splitters, mirrors or waveguides to project the image to the user’s eyes, but it will cause poor optical efficiency (less than 35%) and high power consumption, while the direct-view type will require a certain amount of power. The viewing angle causes the overall device design to be too bulky (for example, the thickness is greater than 100 mm). In addition, the eye-fitting distance of the existing direct-viewing near-eye display devices is often too small (less than 50 mm), resulting in poor user experience. In addition, the existing direct-view near-eye display device allows the user to watch an actual scene while simultaneously watching the displayed images generated by the direct-view near-eye display device, but it often causes the problem of distortion of the actual scene and the inability to clearly image.

The main purpose of the present invention is to provide an optical module, which is defined with a display side and an eye side. The optical module includes: a first lens unit located on the eye side; a second lens unit located on the display Display side; and a transparent display unit, arranged between the first lens unit and the second lens unit, for emitting a light beam so that the light beam enters the eyes of the user located on the eye side through the first lens unit , For the user's eyes to see the augmented reality virtual image located on the display side; wherein the light emitted by the environmental background located on the display side sequentially passes through the second lens unit, the transparent display unit and the The first lens unit shoots into the eyes of the user on the eye side, so that the eyes of the user can see the image of the environment background on the display side.

As in the aforementioned optical module, the first lens unit has a positive refractive power, and the second lens unit has a negative refractive power.

As in the aforementioned optical module, the optical module satisfies the following conditions: -2< f 2/ f 1<-0.5, f 2 is the equivalent focal length of the second lens unit, and f 1 is the equivalent focal length of the first lens unit Equivalent focal length.

As in the aforementioned optical module, the optical module satisfies the following conditions: 0.5< f 1/ t <2, f 1 is the equivalent focal length of the first lens unit, and t is the eye-catching distance of the optical module.

As in the aforementioned optical module, the first lens unit or the second lens unit is a single lens.

As in the aforementioned optical module, the first lens unit or the second lens unit is a lens group composed of at least two lenses.

As in the aforementioned optical module, the first lens unit or the second lens unit is a Fresnel lens.

As in the aforementioned optical module, the formation of the optical surface of the first lens unit or the second lens unit is calculated by even-order aspheric coefficients.

As in the aforementioned optical module, the surface of the first lens unit or the second lens unit is a circularly symmetric surface, a cylindrical surface or a continuous curved surface.

As in the aforementioned optical module, the optical module can be arranged in an array in plural.

With the design that the first lens unit has positive refractive power, the second lens unit has negative refractive power, and the transparent display unit is arranged between the first lens unit and the second lens unit in the optical module of the present invention, the image of the transparent display unit can be The imaging is out of the eye distance, and the image of the environment background can be clearly imaged at the same time, so the user's eyes do not need to focus repeatedly, which has the effect of good user experience, and can increase the user's viewing of the environment background through the optical module of the present invention The correctness.

100: Optical module

101: eye side

102: display side

110: The first lens unit

1101, 1102: lens

120: second lens unit

130: Transparent display unit

131: beam

132: Augmented Reality Virtual Image

200: eyes

300: Image of environmental background

D1: Eye-fitting distance

D2: distance

Fig. 1A is a schematic diagram of the optical module of the present invention.

Fig. 1B is a distant view of Fig. 1A.

FIG. 1C is a schematic diagram of the operation of the optical module of the present invention.

2 and 3 are light spot diagrams of an embodiment of the optical module of the present invention.

4 and 5 are graphs of the modulation transfer function of an embodiment of the optical module of the present invention.

6 and 7 are diagrams of field curvature and distortion of the optical path of an embodiment of the optical module of the present invention.

The following specific examples illustrate the implementation of the present invention, and those skilled in the art can easily understand the other advantages and effects of the present invention from the contents disclosed in this specification, and can also use other different specific embodiments. To implement or apply.

Please refer to FIGS. 1A and 1B at the same time. The present invention is an optical module 100 that can be applied to various augmented reality devices, or other equipment, devices, and articles (such as helmets and goggles). The present invention does not Limit the application area. The optical module 100 can be defined with a display side 102 and an eye side 101, among which, The eye side 101 is the side close to the user's eyes 200, and the display side 102 is the side far away from the user's eyes. In this embodiment, the optical module 100 includes a first lens unit 110, a second lens unit 120, and a transparent display unit 130. The first lens unit 110 is located on the eye side 101, and the second lens unit 120 is located on the display side 102. The transparent display unit 130 is arranged between the first lens unit 110 and the second lens unit 120.

In this embodiment, the first lens unit 110 has a positive refractive power, and the second lens unit 120 has a negative refractive power. In addition, the first lens unit 110 or the second lens unit 120 may be a single lens, or a lens group composed of at least two lenses, or a doublet lens, a triplet lens, etc. The invention is not limited thereto. In an embodiment, the first lens unit 110 or the second lens unit 120 may be a Fresnel lens (Fresnel lens) or a general conventional lens, and in the embodiment of a lens group, part of it may be a Fresnel lens And some are general traditional lenses to form the lens group, or all are Fresnel lenses, all are general traditional lenses to form the lens group, or are composed of different numbers of convex lenses and concave lenses to form a lens group, etc., the present invention It is not limited to this, as long as the first lens unit 110 finally has a positive refractive power, and the second lens unit 120 finally has a negative refractive power.

In one embodiment, the formation of the optical surface of the first lens unit 110 or the second lens unit 120 can be calculated by even-order aspheric coefficients, for example, by the following formula:

Among them, Z is the offset of the optical axis (sag), k is the quadric coefficient, A ₄ ~ A ₈ respectively represent the aspheric coefficients of the aspheric polynomials, and C is the reciprocal of the radius of the Osculating Sphere ( That is, the reciprocal of the radius of curvature close to the optical axis), s is the height of the aspheric surface (the height from the center of the lens to the edge of the lens).

In one embodiment, the surface shape of the first lens unit 110 or the second lens unit 120 may be a circularly symmetric surface, a cylindrical surface, a continuous curved surface, or other free surface forms, and the present invention is not limited thereto.

In this embodiment, the transparent display unit 130 may be a transparent display. The so-called transparent display means that the user can see the image in the display and the environmental background image behind the display at the same time through the display. The transparent display can be, for example, an organic light-emitting diode display, a liquid crystal display, or other flat-panel displays with a rectangular pixel array. The transparent display unit 130 is used to emit a light beam 131, which is incident through the first lens unit 110 into the user's eye 200 located on the eye side 101, so that the eye 200 can see an augmented reality virtual image 132 located on the display side 102 . Since the transparent display unit 130 is a transparent display, the user's eyes 200 can also see the image 300 of the environment background on the display side 102 through the transparent display (as shown in FIG. 1C). That is, the light emitted from the environmental background on the display side 102 (which can be regarded as parallel light at infinity) can pass through the second lens unit 120, the transparent display unit 130, and the first lens unit 110 in sequence, and then enter the eye The eyes 200 of the user on the side 101 are such that the eyes 200 can see the image 300 of the environment background on the display side 102. Therefore, as shown in FIG. 1C, the optical module 100 of the present invention allows the user's eyes 200 to simultaneously see the augmented reality virtual image 132 (such as driving information, navigation information, etc.) in the image 300 of the environment background. The correction of the second lens unit 120 can make the image 300 of the environment background can be clearly formed.

In this embodiment, the optical module 100 satisfies the following conditions:

-2< f 2/ f 1<-0.5

Among them, f 2 is the equivalent focal length of the second lens unit 120, and f 1 is the equivalent focal length of the first lens unit 110. The equivalent focal length compensation design of the second lens unit 120 under this condition can make the image 300 of the environmental background clear imaging, and reduce the distortion of the image 300 of the environmental background by less than 10%, and the angular magnification is 0.5 to 2 times between.

In this embodiment, the optical module 100 satisfies the following conditions:

0.5< f 1/ t <2

Wherein, f 1 is the equivalent focal length of the first lens unit 110, and t is the eye-catching distance of the optical module 100. Under this condition, the first lens unit 110 can image the information of the transparent display unit 130 beyond the eye-catching distance, and the angular magnification is between 1 to 5 times.

In one embodiment, the optical module 100 may be plural, and may be arranged in an array, such as a surface array or a linear array, and the present invention is not limited thereto. When there are a plurality of optical modules 100, it means that the number of augmented reality virtual images 132 on the display side 102 that can be viewed by the user's eyes 200 can be increased to further increase the amount of displayed information.

In one embodiment, the material of the first lens unit 110 or the second lens unit 120 may be, for example, polymethylmethacrylate (PMMA), polycarbonate (PC), or cyclic olefin copolymer (COC). Or ultraviolet curing glue (UV glue), etc., but the present invention is not limited to this. In addition, the first lens unit 110 and the second lens unit 120 can have flexibility after being thinned to adapt to the surface curvature of various carriers (for example, they can be placed on the goggles of a helmet), and can increase the field of view of the display. angle.

Based on the above description of the optical module of the present invention, the optical specifications of an embodiment of the optical module of the present invention will be described in detail below. It should be noted that the optical specifications described below are only one embodiment of the present invention, and are not intended to limit the present invention.

The first lens unit 110 can be composed of a lens 1101 and a lens 1102. The lens 1101 can be a general traditional plastic lens, and the radius of curvature R1 on the surface of the eye side 101 is 9.427, and the conic K1 is 0, and the radius of curvature R2 on the surface of the display side 102 is -34.191, and the quadratic curve K2 is 0. It can be formed of, for example, APL5014DP produced by Mitsui Chemicals, with a thickness of 8mm. The lens 1102 can be a Fresnel lens. The radius of curvature R1 on the surface of the eye side 101 is -7.307, the conic K1 is 0, and the radius of curvature R2 on the surface of the display side 102 is infinite, the conic K2 is 0, and can be formed by ultraviolet curing glue, the thickness is only 0.03mm, and the distance between it and the lens 1101 is 2mm.

The radii of curvature R1 and R2 on the surface of the transparent display unit 130 and the surface of the display side 102 are both infinite, the quadratic curves K1 and K2 are both 0, and the distance from the lens 1102 is 18.566 mm.

The second lens unit 120 may be a Fresnel lens, the radius of curvature R1 on the surface of the eye side 101 is -15.045, the conic K1 is 0, and the radius of curvature R2 on the surface of the display side 102 is infinite, The quadratic curve K2 is 0 and can be formed by a UV curable adhesive, with a thickness of only 0.03 mm, and a distance from the transparent display unit 130 to 0.5 mm. In addition, the second lens unit 120 or the lens 1102 can be attached to a substrate, the substrate is formed of PET material, and its thickness is 0.188 mm.

After the above-mentioned optical specifications of the present invention are tested experimentally, when the eye-catching distance D1 is 7cm, the distance D2 between the augmented reality virtual image 132 and the eye 200 is 80cm, and the angular magnification is 0.58 times, and the thickness of the optical module 100 is less than At the same time, the total thickness of the augmented reality device equipped with the optical module 100 can be less than 5 cm.

Please refer to Figures 2 to 7. Figure 2 represents the light spot diagram of the display light path in the characteristics of the forward optical system from the display side to the eye side, and Figure 4 represents the modulation and transmission of the display light path in the characteristics of the forward optical system from the display side to the eye side. Function (modulation transfer function, MTF) graph. Figure 6 represents the field curvature and distortion of the display optical path from the display side to the eye side. Figure 3 represents the display side to the eye side. The light spot diagram of the environmental background image light path, Figure 5 represents the curve diagram of the modulation transfer function of the environmental background image light path in the characteristics of the forward optical system from the display side to the eye side, Figure 7 Represents the field curvature and distortion of the ambient background image in the characteristics of the forward optical system from the display side to the eye side. It can be seen from FIGS. 2 to 7 that the optical module of the present invention has good optical quality. For example, the distortion amount of the image 300 of the environment background is less than 10%, the distortion amount of the augmented reality virtual image 132 is less than 5%, and the optical system efficiency is greater than 70%, the viewing angle is greater than 25 degrees, and the eye-catching distance is between 0.5 and 30 cm.

In summary, by the design of the optical module of the present invention that the first lens unit has positive refractive power, the second lens unit has negative refractive power, and the transparent display unit is arranged between the first lens unit and the second lens unit, the The image of the transparent display unit is imaged beyond the eye-fitting distance, and can also make the image of the environment background clear imaging, so the user's eyes do not need to focus repeatedly, and it has the effect of good user experience, especially the distortion of the environment background image It can be less than 10%, and the distortion of the augmented reality virtual image can be less than 5%, which can increase the accuracy of the user viewing the environment background through the optical module of the present invention. In addition, the optical module of the present invention is a direct-view architecture design, and the display optical path and the environmental background image optical path do not need to use a beam splitter, a reflector or a waveguide to couple the dual optical paths, which can save costs.

The above-mentioned embodiments are only illustrative to illustrate the technical principles, features and effects of the present invention, and are not intended to limit the scope of the present invention. Anyone familiar with this technology can do the same without departing from the spirit and scope of the present invention. The above embodiment is modified and changed. However, any equivalent modifications and changes made by using the teachings of the present invention should still be covered by the scope of the following patent applications. The scope of protection of the rights of the present invention shall be as listed in the following patent scope.

100: Optical module

101: eye side

102: display side

110: The first lens unit

1101, 1102: lens

120: second lens unit

130: Transparent display unit

131: beam

200: eyes

Claims (8)

An optical module is defined with a display side and an eye side. The optical module includes: a first lens unit located on the eye side; a second lens unit located on the display side; and a transparent display unit located on the first lens Between the unit and the second lens unit, a light beam is used to emit a light beam through the first lens unit to enter the eyes of the user on the eye side for the user’s eyes to see that it is on the display side The augmented reality virtual image; wherein the light emitted from the environmental background on the display side sequentially passes through the second lens unit, the transparent display unit, and the first lens unit to enter the user on the eye side Eyes, for the user's eyes to see the image of the environmental background on the display side, wherein the first lens unit has positive refractive power, and the second lens unit has negative refractive power, and meets the following conditions: -2< f 2/ f 1<-0.5, f 2 is the equivalent focal length of the second lens unit, and f 1 is the equivalent focal length of the first lens unit. The optical module according to claim 1, which satisfies the following conditions: 0.5< f 1/ t <2, f 1 is the equivalent focal length of the first lens unit, and t is the eye-catching distance of the optical module. The optical module according to claim 1, wherein the first lens unit or the second lens unit is a single lens. The optical module according to claim 1, wherein the first lens unit or the second lens unit is a lens group composed of at least two lenses. The optical module according to claim 1, wherein the first lens unit or the second lens unit is a Fresnel lens. The optical module according to claim 1, wherein the formation of the optical surface of the first lens unit or the second lens unit is calculated by even-order aspheric coefficients. The optical module according to claim 1, wherein the surface of the first lens unit or the second lens unit is a circularly symmetric surface, a cylindrical surface or a continuous curved surface. The optical module according to claim 1, which can be arranged in an array in plural.

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