Optical device for generating holographic images
The optical device adjusts holographic image positions using a spatial light modulator and lenses with specific optical designs, addressing mechanical simplicity and durability challenges in holographic image generation.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- EPIC OPTIX CO LTD
- Filing Date
- 2024-12-13
- Publication Date
- 2026-06-18
AI Technical Summary
Existing optical devices for generating holographic images face challenges in adjusting image position while maintaining mechanical simplicity and durability, particularly when using mechanical movement of optical modulators.
An optical device structure that adjusts the diopter of a virtual image using a spatial light modulator and lenses with specific optical designs, minimizing aberrations and allowing for image position change without mechanical complexity.
Enables simple and durable adjustment of holographic image positions by using lenses with predetermined optical designs, reducing mechanical complexity and minimizing aberrations.
Smart Images
Figure KR2024096880_18062026_PF_FP_ABST
Abstract
Description
Optical device that generates holographic images
[0001] The present invention relates to an optical device for generating holographic images using a computer-generated hologram.
[0002] Recently, due to advancements in optical technology, various optical devices are being developed to generate more realistic holographic images. In particular, devices utilizing computer-generated hologram (CGH) technology using optical elements such as holographic optical elements (HOE) and reflective spatial light modulators (SLM) are attracting attention. This technology operates by generating high-resolution holographic images using laser light sources, SLMs, and HOEs.
[0003] However, depending on the usage environment or the physical arrangement of the device, a problem arises where the image position of the holographic image must be changed. To solve this, a method of adjusting the image by physically moving the optical modulator along the optical axis is commonly used. While this method has the advantage of a simple structure, it has the disadvantage of increased mechanical complexity and poor durability because the optical modulator must be moved mechanically.
[0004] Therefore, there is an increasing demand for technology that can change the position of holographic images in a simple manner while maintaining excellent durability.
[0005] The present invention aims to provide a structure for adjusting the diopter of an optical device by changing the position of a virtual image reflected by a spatial light modulator using a computer-generated hologram.
[0006] The present invention aims to provide an optical device that minimizes aberrations by using lenses that satisfy a plurality of predetermined optical designs.
[0007] An optical device for generating a holographic image according to the present invention comprises: a laser light source that irradiates parallel light; a first optical system including a reflective spatial light modulator (SLM) that reflects light generated by the laser light source and modulates it by a computer-generated hologram (CGH); a second optical system including a non-diffractive reflection removal filter into which light reflected from the spatial light modulator is incident, which has positive power, which removes non-diffractive reflection light and passes diffractive reflection light; a third optical system into which light that has passed through the non-diffractive reflection removal filter is incident and which has positive power; a mirror having a predetermined thickness and including a front surface and a rear surface, into which light passing through the third optical system is incident and refracted by a first refraction, into which the first refracted light is reflected from the rear surface, and into which the reflected light is emitted and refracted by a second refraction, and a reflective holographic optical element (HOE) into which light reflected from the mirror is reflected and which has positive power; and a virtual image whose position can be changed by the spatial light modulator. An intermediate holographic image is formed between the mirror and the reflective optical element.
[0008] In one embodiment of the present invention, the mirror may be formed of glass having a predetermined thickness and may include a reflective coating formed on the rear surface.
[0009] In one embodiment of the present invention, the second optical system may include a first lens having positive refractive power and having both sides formed as convex surfaces arranged in the direction of the third optical system from the first optical system, a second lens joined to the first lens having negative refractive power and having an exit surface formed as a flat surface, and a non-diffracted reflected light removal filter.
[0010] In one embodiment of the present invention, the first optical system may further include a polarizer located between the spatial light modulator and the second optical system.
[0011] In one embodiment of the present invention, the third optical system may further include at least one cylindrical lens.
[0012] In one embodiment of the present invention, when the power with respect to the first axis of the cylindrical lens is denoted as A and the power with respect to the second axis orthogonal to the first axis is denoted as B, the following condition 1 and condition 2 can be satisfied.
[0013] <Condition 1>
[0014] A < 0
[0015] <Condition 2>
[0016] |B| < 0.2|A|
[0017] In one embodiment of the present invention, the third optical system may include a third lens, which is a cylindrical lens arranged in the mirror direction in the second optical system; a fourth lens, which has a concave incident surface and a convex exit surface and has negative refractive power; a fifth lens, which has a convex incident surface and a concave exit surface and has positive refractive power; a sixth lens, which has a convex incident surface and a concave exit surface and has positive refractive power; a seventh lens, which has a concave incident surface and a concave exit surface and has negative refractive power; an eighth lens, which has a concave incident surface and a concave exit surface and has negative refractive power; and a ninth lens, which has a concave incident surface and a convex exit surface and has positive refractive power.
[0018] In one embodiment of the present invention, the following condition 3 can be satisfied.
[0019] <Condition 3>
[0020] 0.95< efx / efy< 1.00
[0021] Here, efx is the effective focal length along the x-axis (short axis) and efy is the effective focal length along the y-axis (long axis).
[0022] In one embodiment of the present invention, when the focal length of the fourth optical system is denoted as f4, the following condition 4 can be satisfied.
[0023] <Condition 4>
[0024] 19mm < f4 < 22mm
[0025] In one embodiment of the present invention, when the x-axis focal length of the second optical system is denoted as f2x and the y-axis focal length as f2y, and the x-axis focal length of the third optical system is denoted as f3x and the y-axis focal length as f3y, the following condition 5 can be satisfied.
[0026] <Condition 5>
[0027] 0.9 < {(f3x / f2x)+(f3y / f2y)} / 2 < 1.1
[0028] The present invention has the advantage of being able to adjust the diopter of an optical device by changing the position of a virtual image reflected by a spatial light modulator using a computer-generated hologram.
[0029] The present invention has the advantage of being able to minimize aberrations by using lenses that satisfy a plurality of predetermined optical designs.
[0030] FIG. 1 is a drawing illustrating the optical structure of an optical device for generating a holographic image according to one embodiment of the present invention.
[0031] FIG. 2 is a diagram illustrating the optical structure of a first optical system and a second optical system of an optical device for generating a holographic image according to an embodiment of the present invention.
[0032] FIG. 3 is a diagram illustrating the optical structure of a third optical system of an optical device for generating a holographic image according to one embodiment of the present invention.
[0033] FIG. 4 is a table for explaining the optical structure of an optical device for generating a holographic image according to one embodiment of the present invention.
[0034] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Identical or similar components regardless of drawing symbols are assigned the same reference number, and redundant descriptions thereof will be omitted. Furthermore, in describing the embodiments disclosed in this specification, if it is determined that a detailed description of related prior art could obscure the essence of the embodiments disclosed in this specification, such detailed description will be omitted.
[0035] Terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. These terms are used solely for the purpose of distinguishing one component from another.
[0036] A singular expression includes a plural expression unless the context clearly indicates otherwise.
[0037] In this application, each step described may be performed regardless of the order listed, except where it must be performed in the order listed by a particular causal relationship.
[0038] In this application, terms such as “comprising” or “having” are intended to specify the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.
[0039]
[0040] The present invention will be described below with reference to the attached drawings.
[0041] FIG. 1 is a drawing illustrating the optical structure of an optical device for generating a holographic image according to one embodiment of the present invention.
[0042] Referring to FIG. 1, the optical device of the present invention generates a holographic image. The optical device of the present invention has the pupil of the wearer's eye corresponding to an object (700), and the focus of the object is formed at the position of the true focus of the holographic image of the present invention.
[0043] The optical device of the present invention includes a laser light source (100), a first optical system (200), a second optical system (300), a third optical system (400), a mirror (500), and a fourth optical system (600). Here, the laser light source (100), the first optical system (200), the second optical system (300), the third optical system (400), the mirror (500), and the fourth optical system (600) are arranged sequentially from the laser light source (100) toward the object (700).
[0044] The laser light source (100) generates light and irradiates the generated light onto the first optical system (200). In particular, the laser light source (100) generates parallel light and irradiates it onto the spatial light modulator (210) of the first optical system (200).
[0045] In the present invention, it is preferable that the light source be a laser light source. In the present invention, the reflective holographic optical element (610) has a narrow wavelength range, so chromatic aberration may occur if an LED with a wide wavelength range is used.
[0046] The first optical system (200) includes a spatial light modulator (SLM) (210). Here, the spatial light modulator (SLM) (210) refers to a device that generates a virtual image by modulating light generated by a laser light source using a computer-generated hologram (CGH). In the present invention, the spatial light modulator (210) may be of a reflective type, for example, an LCoS (Liquid Crystal on Silicon) spatial light modulator. The spatial light modulator (210) has the characteristic of forming a holographic image by modulating light generated by a light source and being able to adjust its position.
[0047] Here, LCoS (Liquid Crystal on Silicon) refers to a reflective digital display technology that controls light polarization by placing liquid crystals on a silicon substrate. LCoS can generate a desired image by changing the arrangement of liquid crystals according to electrical signals and thereby controlling the characteristics of the reflected light.
[0048] The first optical system (200) may further include a polarizer (220). In particular, if a reflective type of spatial light modulator (210) is used, the polarizer (220) may be included as a necessity. The polarizer (220) is positioned between the spatial light modulator (210) and the second optical system (300). Here, the polarizer (220) refers to an optical element that selectively passes only light of a specific polarization direction.
[0049] The second optical system (300) receives light reflected from the spatial light modulator (210). If the first optical system (200) includes a polarizer (220), the second optical system (300) may receive only light with aligned polarization.
[0050] The second optical system (300) may have positive power (refractive power) overall. The second optical system (300) may include at least one lens. Specifically, the second optical system (300) may include a first lens (310) and a second lens (320). The first lens (310) and the second lens (320) may be arranged sequentially from the light source side toward the object side.
[0051] The first lens (310) may have a defined power. The first lens (310) is preferably a lens that is convex on both sides, but in some cases, a lens that is convex on at least the side facing the light source may be used.
[0052] The second lens (320) can have negative power. The second lens (320) can be formed with a concave surface on the light source side and a flat surface on the object side.
[0053] The second optical system (300) may include a non-diffracted reflected light removal filter (DC filter) (330). The non-diffracted reflected light removal filter (330) is located on the object side of the second lens (320) and blocks a portion of the non-diffracted reflected light among the light passing through the second lens (320), and allows only the remaining light to pass through. Specifically, the non-diffracted reflected light removal filter (330) blocks the 0th-order diffracted light that is not diffracted and selectively allows only the 1st-order or higher diffracted light to pass through.
[0054] Here, the non-diffractive reflection removal filter (330) refers to an optical element that serves to remove non-diffractive light (Diffractive Component) that is not diffracted in the optical path. Specifically, the non-diffractive reflection removal filter (330) primarily blocks zero-order diffractive light, that is, light generated from a laser light source and transmitted as is without separate modulation, thereby reducing unnecessary noise within the system and selectively allowing only first-order or higher diffractive light to pass through during the process of forming a holographic image.
[0055] The third optical system (400) receives light that has passed through the non-diffracted reflected light removal filter (330). Therefore, the third optical system (400) receives only the diffracted light among the reflected light of the light source (100) that has passed through the second optical system (300).
[0056] The third optical system (400) may have a defined power overall. The third optical system (400) may include at least one lens. Specifically, the third optical system (400) may include a third lens (410), a fourth lens (420), a fifth lens (430), a sixth lens (440), a seventh lens (450), an eighth lens (460), and a ninth lens (470). The third lens (410), the fourth lens (420), the fifth lens (430), the sixth lens (440), the seventh lens (450), the eighth lens (460), and the ninth lens (470) may be arranged sequentially from the light source (100) side toward the object (700) side.
[0057] In the attached drawing, the third optical system (400) is shown with seven lenses arranged sequentially, but the number of individual lenses may be changed depending on the case.
[0058] The third optical system (400) includes at least one cylindrical lens. In the attached drawing, the third lens (410) located closest to the light source (100) among the lenses of the third optical system (400) is shown as a cylindrical lens.
[0059] The third lens (410) is a cylindrical lens located on the side of the light source (100) and has the characteristic of having refractive power only in a specific axis direction. The third lens (410) can be formed to have negative power for the first axis and no separate power for the second axis. Here, the first axis may be the y-axis (major axis) in the vertical direction, and the second axis may be the x-axis (minor axis) in the horizontal direction.
[0060] Specifically, the light source side surface of the third lens (410) can be formed as a concave surface with respect to the first axis and a flat surface with respect to the second axis, and the object side surface can be formed as a flat surface.
[0061] Specifically, when the power for the first axis of the third lens (410), which is a cylindrical lens, is denoted as A and the power for the second axis orthogonal to the first axis is denoted as B, the following condition 1 and condition 2 are satisfied.
[0062] <Condition 1>
[0063] A < 0
[0064] <Condition 2>
[0065] |B| < 0.2|A|
[0066] <Condition 1> means that the cylindrical lens (410) has negative power with respect to the first axis. <Condition 2> means that the cylindrical lens (410) has power with respect to the second axis that is smaller in absolute value compared to the first axis. Specifically, since the absolute value of the power with respect to the second axis is within 0.2 times the absolute value of the power with respect to the first axis, it indicates that there is virtually no refractive power in the direction of the second axis.
[0067] With this cylindrical lens (410), the optical device of the present invention satisfies the following condition 3.
[0068] <Condition 3>
[0069] 0.95< efx / efy< 1.00
[0070] Here, efx is the effective focal length along the x-axis (short axis) and efy is the effective focal length along the y-axis (long axis).
[0071] The fourth lens (420) may be a meniscus-shaped lens. The fourth lens (420) may have negative power, and the light source side surface may be formed as a concave surface, and the object side surface may be formed as a convex surface.
[0072] The fifth lens (430) may be a meniscus-shaped lens. The fifth lens (430) may have a defined power, and the light source side surface may be formed as a convex surface, and the object side surface may be formed as a concave surface.
[0073] The sixth lens (440) may be a meniscus-shaped lens. The sixth lens (440) may have a defined power, and the light source side surface may be formed as a convex surface, and the object side surface may be formed as a concave surface.
[0074] The seventh lens (450) has negative power, and the light source side surface can be formed as a concave surface, and the object side surface can be formed as a concave surface.
[0075] With the power of the 8th lens (460), the light source side surface can be formed as a concave surface and the object side surface can be formed as a concave surface.
[0076] The ninth lens (470) may be a meniscus-shaped lens. The ninth lens (470) may have a defined power, and the light source side surface may be formed as a concave surface, and the object side surface may be formed as a convex surface.
[0077] With these second optical system and third optical system, the optical device of the present invention satisfies the following condition Equation 5.
[0078] <Condition 5>
[0079] 0.9 < {(f3x / f2x)+(f3y / f2y)} / 2 < 1.1
[0080] Here, f2x is the x-axis focal length of the second optical system (300), f2y is the y-axis focal length of the second optical system (300), f3x is the x-axis focal length of the third optical system (400), and f3y is the y-axis focal length of the third optical system (400).
[0081] The mirror (500) reflects light that has passed through the third optical system (400). Due to the reflection shape of this mirror (500), the optical device of the present invention can be designed in the shape of glasses overall.
[0082] Here, the mirror (500) may be formed of glass having a predetermined thickness and has a structure in which a reflective coating is formed on the rear surface.
[0083] The fourth optical system (600) includes a reflective holographic optical element (HOE) (610) that reflects light reflected from the mirror (500) and has positive power. Here, the reflective holographic optical element (HOE) (610) is an element having off-axis reflection characteristics. Therefore, even if the reflective holographic optical element (HOE) (610) is positioned in a shape close to perpendicular to the wearer's face, it can generate outgoing light incident perpendicularly on the wearer's eyeball. An intermediate holographic image (510) is formed between the mirror (500) and the reflective optical element by the reflective holographic optical element (610).
[0084] With this fourth optical system (600), the optical device of the present invention satisfies the following condition 4.
[0085] <Condition 4>
[0086] 19mm < f4 < 22mm
[0087] Here, f4 is the focal length of the fourth optical system (600).
[0088] Hereinafter, with reference to FIG. 2, a virtual image (250) generated by a computer-generated hologram in the present invention will be described. The virtual image generated by a computer-generated hologram may correspond to a virtual image.
[0089] The virtual image (250) can be repositioned by a computer-generated hologram. Specifically, the virtual image (250) can be repositioned within a range of the front-back direction relative to the spatial light modulator (210). Although the virtual image (250) is shown in the attached FIG. 2 as being located between the spatial light modulator (210) and the second optical system (300), in some cases, the virtual image (250) may be generated as a virtual image behind the spatial light modulator (210).
[0090] As the position of the virtual image (250) changes, the position of the intermediate holographic image (510) generated by the optical device of the present invention may be moved.
[0091]
[0092] Hereinafter, with reference to FIG. 3, the position and arrangement form of the reflective holographic optical element (HOE) (610) in the present invention will be described in detail.
[0093] Light reflected from the mirror (500) is reflected in the fourth optical system (600), and there may be a virtual first axis (611) connecting the reflective holographic optical element (610) and the object (700). Additionally, there may be a virtual second axis (612) connecting the reflective holographic optical element (610) and the intermediate holographic image (550).
[0094] Here, the angle between the first axis (611) and the second axis (612) may be 50° to 70°.
[0095] Additionally, the reflective holographic optical element (610) may be positioned at an angle of 0° to 5° with respect to the first axis (611). Depending on the tilt arrangement of the reflective holographic optical element (610), aberrations caused by off-axis reflection in the holographic optical element (610) can be reduced.
[0096] By operating the optical device described above, the user's pupil (700) corresponding to the object can view holographic images (561, 562). Here, the position of the holographic images (561, 562) can be adjusted by adjusting the position of the virtual image (250) described above. Specifically, as shown in FIG. 3, if the optical device is set to 2.0 diopters, a holographic image (561) corresponding to a position separated by a distance (D1) of 0.5 m from the object is generated. Additionally, if the optical device is set to 0.0 diopters, a holographic image (562) corresponding to a position separated by an infinite distance (D2) from the object is generated.
[0097]
[0098] FIG. 4 illustrates optical data for individual lenses included in an optical device according to one embodiment of the present invention.
[0099]
[0100] The technical features disclosed in each embodiment of the present invention are not limited to that embodiment only, and as long as they are not mutually incompatible, the technical features disclosed in each embodiment may be combined and applied to different embodiments.
[0101] Therefore, in each embodiment, the technical features are described primarily, but as long as the technical features are not mutually incompatible, they may be combined and applied together.
[0102] The present invention is not limited to the embodiments described above and the attached drawings, and various modifications and variations may be possible from the perspective of those skilled in the art to which the present invention belongs. Accordingly, the scope of the present invention should be defined not only by the claims of this specification but also by equivalents thereof.
Claims
1. A laser light source that emits parallel light; A first optical system comprising a reflective spatial light modulator (SLM) that reflects light generated by the above laser light source and modulates it by a computer-generated hologram (CGH); A second optical system comprising a non-diffraction reflection removal filter having a defined power, into which light reflected from the above spatial light modulator is incident, and which removes non-diffraction reflection light and passes diffraction reflection light; Light passing through the above-mentioned non-diffraction reflection removal filter is incident on a third optical system having a positive power; A mirror having a predetermined thickness, including a front surface and a rear surface, wherein light passing through the third optical system is incident through the front surface and is refracted by a first degree, the first-degree refracted light is reflected from the rear surface, and the reflected light is emitted through the front surface and is refracted by a second degree; It includes a fourth optical system comprising a reflective holographic optical element (HOE) having a defined power, into which light reflected from the mirror is reflected, and A virtual image whose position can be changed by the above spatial light modulator is formed, and An intermediate holographic image is formed between the mirror and the reflective optical element. Optical device that generates holographic images.
2. In Paragraph 1, The above mirror is formed of glass having the above-mentioned predetermined thickness and includes a reflective coating formed on the above-mentioned rear surface. Optical device that generates holographic images.
3. In Paragraph 1, The above second optical system is, Arranged in the direction of the third optical system from the first optical system, A first lens having both sides formed as convex surfaces and positive refractive power; A second lens joined to the first lens, having an exit surface formed as a flat plane and having negative refractive power; and The above non-diffraction reflection removal filter Optical device that generates holographic images.
4. In Paragraph 1, The first optical system further includes a polarizer located between the spatial light modulator and the second optical system. Optical device that generates holographic images.
5. In Paragraph 1, The third optical system further includes at least one cylindrical lens. Optical device that generates holographic images.
6. In Paragraph 5, Let A be the power about the first axis of the above cylindrical lens and B be the power about the second axis orthogonal to the first axis, satisfying the following condition 1 and condition 2 Optical device that generates holographic images. <Condition 1> A < 0 <Condition 2> |B| < 0.2|A| 7. In Paragraph 1, The third optical system is arranged in the mirror direction in the second optical system, A third lens that is a cylindrical lens; A fourth lens having a concave incident surface, a convex exit surface, and negative refractive power; A fifth lens having a convex surface of incidence, a concave surface of exit, and positive refractive power; A sixth lens having a convex surface of incidence, a concave surface of exit, and positive refractive power; A seventh lens having a concave incident plane, a concave exit plane, and negative refractive power; An eighth lens having a concave incident surface, a concave exit surface, and negative refractive power; and A ninth lens having a concave incident surface, a convex exit surface, and positive refractive power Optical device that generates holographic images.
8. In Paragraph 1, satisfying the following condition 3 Optical device that generates holographic images. <Condition 3> 0.95< efx / efy< 1.00 Here, efx is the effective focal length along the x-axis (short axis) and efy is the effective focal length along the y-axis (long axis).
9. In Paragraph 1, Let f4 be the focal length of the above fourth optical system, satisfying the following condition 4 Optical device that generates holographic images. <Condition 4> 19mm < f4 < 22mm 10. In Paragraph 1, Let the x-axis focal length of the second optical system be f2x and the y-axis focal length be f2y, and Let f3x be the x-axis focal length and f3y be the y-axis focal length of the above third optical system, satisfying the following condition Equation 5 Optical device that generates holographic images. <Condition 5> 0.9 < {(f3x / f2x)+(f3y / f2y)} / 2 < 1.1