KR20210031597A - Eye accommodation distance measuring device and method for head mounted display, head mounted display - Google Patents

Abstract

Disclosed are a device and a method for determining an adaptive distance of an eye for a head-mounted display. The device of the present invention comprises: an interferometer for generating a plurality of frequency-modulated laser beams in different directions, and generating a plurality of interference signals with the laser beam reflected from reflective surfaces of an eye among the laser beams; a signal processing unit for generating a signal spectrum using each of the interference signals; a distance determining unit for determining the distance to the reflective surfaces of the eye for each of the laser beams by analyzing the signal spectrum; a point coordinate determining unit for determining coordinates of points on each of the reflective surfaces of the eye for each of the laser beams on the basis of the determined distance to the reflective surfaces of the eye and information on the direction of each of the laser beams; a re-configuring unit for generating an internal eye structure model on the basis of the determined coordinates of the points on the reflective surfaces of the eye; and an eye adaptive distance determining unit for determining an adaptive distance of the eye on the basis of the internal eye structure model. Accordingly, a user can use an AR/VR device for a long time.

Description

Eye accommodation distance measuring device and method for head mounted display, head mounted display {Eye accommodation distance measuring device and method for head mounted display}

Disclosed embodiments relate to a stereoscopic display, and more particularly, to an apparatus and method for measuring an adaptive distance of an eye for a head mounted display, and a head mounted display that can be used in an augmented/virtual reality system.

The physiological principle of recognizing 3D objects in the real world requires that the eye's focus (accommodation distance) and the eye's convergence point (vergence distance) be matched. In the currently commercialized AR/VR system with a fixed focal length, these values cannot be matched, resulting in a so-called convergence-accommodation conflict (VAC), resulting in fatigue and visual discomfort to the user. When using AR-glasses, the virtual object is out of focus when observing the real object, so the VAC effect complicates the process of matching the real object and the virtual object. This problem can be alleviated by automatically measuring the focus of the eye (gaze tracking) and providing feedback to the AR glasses rendering system.

In addition, there is a problem in that the focus is blurred due to the movement of the eyes. In virtual reality, the usual tour is performed by the rotation of the head, whereas in the real world, it is also performed by the movement of the eyes. In the conventional AR/VR system, the movement of the eyes causes damage to the rendered image. In order to solve this problem, there is a need for a solution that provides eye tracking.

One of the major AR (Augmented Reality System) problems is focus matching on real and virtual objects. If so-called virtual images with real-world objects are placed on different focal planes, each time they stare at objects that should be completely sharp, they will cause the user to change focus due to the inconsistency of blur.

Accordingly, there is a need for a gaze direction and eye focus tracking device that can be integrated into an AR/VR device (eg, AR glasses, VR helmet) and is inexpensive and compact. An additional requirement for such a device is a small delay (fast measurement speed) in measuring the eye safety for the user and the eye's adaptation distance.

As a known prior art, there is a gaze tracking system disclosed in US 2014375541 A1. Known systems use the time of flight (TOF) method to acquire a 2D image of the human eye, track the gaze direction, and determine the distance to the display. Known systems only track the direction of the gaze and cannot obtain information on the adaptation distance of the eye. TOF cameras have the drawback that there is a dead zone close to the camera, which can complicate the design of the camera.

As a known conventional technique, there is a gaze tracking device disclosed in US 2017109562 A1. Known devices use a depth sensor to estimate the gaze direction by measuring the curvature of the anterior surface of the eye. Known devices only track the direction of the gaze and cannot obtain information about the adaptation distance of the eye.

As a known conventional technique, there is a laser optical feedback tomography (LOFT) sensor disclosed in US 20080208022 A1. The known sensor improves the efficiency of the self-mixing interferometry (SMI) performance of the laser by performing a frequency shift optical feedback with respect to the relaxation oscillation frequency of the laser. The drawback of known sensors is that they are constructed using beamsplitters, frequency shifters, and mechanical scanning. US 20080208022 A1 does not disclose an implementation of a sensor suitable for AR/VR devices or intended for eye tracking.

As a known prior art there is a head-mounted display (HMD) disclosed in US 10154254 A1. Known displays include eye tracking systems using TOF cameras. The eye tracking system includes an illumination light source, an imaging device, and a controller. The controller determines depth information about the surface of the eye and creates a model of the eye. Known displays focus primarily on tracking the direction of the gaze. The disadvantage of the display lies in complex signal processing based on image processing of light patterns that are distorted over time. As pointed out above, the TOF camera has the drawback that there is a blind spot at a close distance from the camera, which can complicate the design of the camera.

As a known conventional technique, there is an apparatus for correcting vision using eye tracking and depth detection disclosed in US 2016370605 A1. Known devices include wearable computing devices with variable lenses, eye tracking sensors, and depth sensors. Known devices indirectly estimate the depth of focus and do not provide the required accuracy.

As a known prior art, there is a display system disclosed in US 2017124928 A1. Known systems can acquire images of the projected wide field of view and use the acquired images to determine the depth of focus (or lateral focal position) for various areas of the wide field of view. This system can correct a variety of display defects and aberrations. The image is composed at various depths of focus. The system is based on eye tracking and does not work with depth or focus tracking of the eye.

It provides an apparatus and method for measuring an eye adaptive distance for a head mounted display.

It provides a head mounted display that can be used in an augmented/virtual reality system.

The apparatus for determining the adaptive distance of the eye according to an embodiment generates a plurality of frequency-modulated laser beams in different directions, and generates a plurality of interference signals from the laser beams reflected from the reflective surfaces of the eye among the plurality of laser beams. interferometer; A signal processor for generating a signal spectrum using each of a plurality of interference signals; A distance determining unit that analyzes the signal spectrum and determines a distance to a reflective surface of the eye for each laser beam; A point coordinate determining unit for determining coordinates of points on each reflective surface of the eye for each laser beam based on the determined distance to the reflective surfaces of the eye and information about the direction of each laser beam; A reconstruction unit that generates an eye internal structure model based on the determined coordinates of points on the reflective surface of the eye; And an eye adaptation distance determination unit that determines an eye adaptation distance based on the eye internal structure model.

For the laser beam incident on the retina of the eye, each signal spectrum generated by the signal processing unit has first to fourth peaks in the frequency domain, the first peak corresponds to the surface of the cornea, and the second peak is of the lens. Corresponding to the front surface, the third peak may correspond to the back surface of the lens, and the fourth peak may correspond to the surface of the retina.

The distance determining unit extracts peaks according to the optical path distance of each laser beam from the first to fourth peaks in the frequency domain of each signal spectrum and calculates the distance to the reflective surfaces of the eyes reflecting each laser beam. I can.

The plurality of laser beams are incident on different points on the reflective surfaces of the eye, respectively, and the signal processing unit may generate signal spectra for different points on the reflective surfaces of the eye using the plurality of laser beams. have.

The reconstruction unit approximates the points corresponding to the surface of the cornea, the front surface of the lens, and the rear surface of the lens with a spherical surface, so that the radius of curvature of the cornea, the radius of curvature of the front of the lens, the radius of curvature of the back of the lens, the thickness of the lens, and between the lens and the retina The distance can be obtained, and based on this, an adaptation distance of the eye can be determined.

The reconstruction unit may determine an optical axis direction of the eye in a direction of a line in which centers of the approximate spherical surfaces are located.

The signal processing unit, the distance determination unit, the point coordinate determination unit, the reconstruction unit, and the eye adaptive distance determination unit may be implemented with one software, one semiconductor chip, or one electronic circuit.

The interferometer is a magnetic mixing interferometer including a laser array including a plurality of lasers and a laser array driver supplying a frequency modulated control signal to each laser of the laser array, and the interference signal may be a laser magnetic mixing signal.

The interferometer is a magnetic mixing interferometer including a laser, a laser driver that supplies a frequency modulated control signal to the laser, and an optical-mechanical scanning system, and the interference signal may be a laser magnetic mixing signal.

The interferometer may be configured such that the laser beam reflected from the reflective surfaces of the eye re-enters the cavity of the laser emitting the laser beam.

The interferometer includes a laser array including a plurality of lasers, a laser array driver for supplying a frequency modulated control signal to each laser of the laser array, a detector, a beam splitter, and a reference mirror, and the interference signal is the detector It may be a signal generated by

The interferometer may include a laser, a laser driver for supplying a frequency modulated control signal to the laser, a detector, a beam splitter, a reference mirror, and an optical-mechanical scanning system.

The beam splitter divides the laser beam emitted by the laser into a first beam and a second beam, the first beam is reflected from the reference mirror and the second beam is reflected from the reflective surfaces of the eye, and the reflected first beam The beam and the second beam may form an interference signal in the detector.

The method for determining the adaptive distance of the eye according to another embodiment generates a plurality of laser beams frequency-modulated in different directions, and the beam direction information corresponds to each beam direction, and at least some of the plurality of laser beams are inside the eye. Incident on the reflective surfaces of the structure; Generating an interference signal for each laser beam of the plurality of laser beams; Generating a signal spectrum for each interfering signal from among the plurality of interfering signals; Analyzing a signal spectrum to determine a distance to a reflective surface for each laser beam among the plurality of laser beams; Determining coordinates of points of the eye surface for each beam based on the determined distance to reflective surfaces and beam direction information, within a coordinate system associated with the head mounted display; Generating a model of the internal structure of the eye based on the determined coordinates of points on the eye surface; And determining an adaptation distance of the eye based on the eye internal structure model.

The head mounted display according to another embodiment includes the above-described apparatus for determining the adaptive distance of the eye and a rendering system having an adjustable focal length, and the rendering system having the adjustable focal length is obtained from the apparatus for determining the adaptive distance of the eye. It may have an adjustable focal length that automatically adjusts the focal length based on the adaptation distance of the eye.

According to the disclosed embodiment, it is possible to mitigate the difference between the focus of the eye and the convergence point of the eye. Therefore, the user can use the AR/VR device for a long time. In addition, since the user can change the field of view without losing focus not only by movement of the head but also movement of the eyes, it is possible to give a natural feeling.

1 is a block diagram of an eye accommodation distance determinig device according to an exemplary embodiment.
2 schematically shows the internal structure of an eye reflecting a laser beam.
3 exemplarily shows the signal spectrum generated by the laser beam reflected from the structural surfaces of the eye.
4 shows an analysis of a spectrum of a beam interference signal showing the distance to the reflective surface of the eye structure.
5 exemplarily shows a plurality of beams reflected from the surface of the eye structure.
6 schematically shows an interference signal spectrum of a plurality of beams reflected from the ocular structure surface.
7 shows a model of the internal structure of the eye.
8 shows the effective optical layout of the eye.
9 is a schematic diagram of an apparatus for determining an adaptation distance of an eye according to the first embodiment.
10 is a schematic diagram of an apparatus for determining an adaptive distance of an eye according to a second embodiment.
11 is a schematic diagram of an apparatus for determining an adaptive distance of an eye according to a third exemplary embodiment.
12 is a schematic diagram of an apparatus for determining an adaptive distance of an eye according to a fourth exemplary embodiment.
13 is a schematic diagram of a head mounted display device according to another exemplary embodiment.

Hereinafter, an apparatus and method for measuring an eye adaptive distance for a head mounted display, and a head mounted display will be described in detail with reference to the accompanying drawings. In the following drawings, the same reference numerals refer to the same components, and the size of each component in the drawings may be exaggerated for clarity and convenience of description. In addition, the embodiments described below are merely exemplary, and various modifications are possible from these embodiments.

Hereinafter, what is described as "top" or "top" may include not only those directly above by contact, but also those that are above non-contact. Singular expressions include multiple expressions unless the context clearly indicates otherwise. In addition, when a part "includes" a certain component, it means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

The use of the term "above" and similar designating terms may correspond to both the singular and the plural. Unless explicitly stated or contradictory to the steps constituting the method, these steps may be performed in an appropriate order, and are not necessarily limited to the stated order.

In addition, terms such as "... unit" and "module" described in the specification mean a unit that processes at least one function or operation, which may be implemented as hardware or software or a combination of hardware and software. .

Connections or connecting members of lines between components shown in the drawings are illustrative representations of functional connections and/or physical or circuit connections, and in an actual device, various functional connections, physical connections, alternative or additional, Or it can be represented as circuit connections.

The use of all examples or illustrative terms is merely for describing technical concepts in detail, and the scope is not limited by these examples or illustrative terms unless limited by the claims.

Referring to FIG. 1, an eye accommodation distance determinig device according to an embodiment for a head mounted display includes a laser interferometer 1, a signal processing unit 2, and a distance determining unit. (3), a point coordinate determination unit 4, a reconstruction unit 5, and an eye adaptation distance determination unit 6. In FIG. 1, the signal processing unit 2, the distance determining unit 3, the point coordinate determining unit 4, the reconstruction unit 5, and the eye adaptive distance determining unit 6 are separately illustrated for convenience of description. The signal processing unit 2, the distance determining unit 3, the point coordinate determining unit 4, the reconstruction unit 5, and the eye adaptation distance determining unit 6 are actually one software or one semiconductor chip, Alternatively, it may be implemented as a single electronic circuit.

The laser interferometer 1 generates a plurality of frequency-modulated laser beams in different directions forming a beam bundle, includes outer surfaces of the eye and inner surfaces of the eye, and generates an interference signal for each beam. Detects light reflected from one or more surfaces of the generating eye. For example, the outer surfaces of the eye are the surface of the cornea or the sclera, and the inner surfaces of the eye are the surface of the lens or the surfaces of the retina.

The signal processing unit 2 processes the interference signals to generate a signal spectrum for each signal of a plurality of interference signals generated by the laser interferometer 1.

The spectrum of the signals of the beams reflected from the structural surfaces of the eye has specific peaks at different frequencies corresponding to reflections from different surfaces. For example, referring to FIGS. 2 and 3, the spectrum of signals of beams incident on the pupil of the eye are reflective surfaces of internal and external eye structures, such as the surface of the cornea 7 or sclera 8 , It will have four different frequency peaks corresponding to reflections from the front surface of the lens 9, the back surface of the lens 9, and the surface of the retina 10. Thus, spectral peaks can be interpreted as different reflective surfaces. For example, the first peak corresponds to the surfaces of the cornea 7 and sclera 8 of the eye, the second peak corresponds to the front surface of the lens 9 and the iris, and the third peak corresponds to the lens. It corresponds to the back surface of (9), and the fourth peak corresponds to the surface of the retina 10 of the eye.

The distance determining unit 3, for each laser beam, performs a signal spectrum analysis using an interference technique and determines one or more distances to one or more surfaces reflecting the laser beam. For example, referring to FIG. 4, the distance determination unit 3 extracts 4 peaks according to the optical path distance from the 4 peaks in the frequency domain shown in FIG. 3 through analysis of the signal spectrum, Calculate the distance between the reflective surfaces.

The point coordinate determination unit 4, based on information about the distance to the reflective surfaces for each beam and information about the beam direction (the position of the beam in space), the eye in the coordinate system associated with the head mounted display. Determine the coordinates of the points of the structural surfaces. Each point can be associated with a specific surface of the eye's structure. For example, among the laser beams, the laser beam incident on the eye retina 10 has four reflections, in which case the first peak of the signal spectrum corresponds to a point on the corneal surface, and the second peak of the signal spectrum is Corresponds to a point on the front surface of the lens, the third peak of the signal spectrum corresponds to a point on the back surface of the lens, and the fourth peak of the signal spectrum corresponds to a point on the surface of the retina. In the case of a beam with two reflections, the first peak of the signal spectrum corresponds to the corneal surface, and the first peak of the signal spectrum corresponds to the iris surface. In the case of a beam with one reflection, one single peak corresponds to the sclera or the surface of the sclera or to another surface (if the beam is not incident on the user's eye).

Referring to FIG. 5, a plurality of frequency-modulated laser beams are incident on different points on structural surfaces of the eye, respectively. Accordingly, the positions of the first to fourth peaks of the signal spectrum vary depending on the positions of points on the structural surfaces of the eye to which a plurality of frequency modulated laser beams are incident, as shown in FIG. 6, for example. . The signal processing unit 2 generates a signal spectrum for different points on the structural surfaces of the eye by using a plurality of frequency-modulated laser beams. The distance determining unit 3 determines a distance between surfaces on a path through which the plurality of laser beams travel, respectively, using a plurality of signal spectra obtained from the plurality of laser beams. Then, the point coordinate determining unit 4 may determine coordinates of different points on the structural surfaces of the eye using information provided from the distance determining unit 3.

The reconstruction unit 5 generates an eye structure model based on information on the structural surfaces of the eye. An eye structure model can be created, for example, by approximating points by geometric surfaces. For example, groups of points corresponding to the corneal surface, the front surface of the lens, and the back surface of the lens may be approximated by a spherical surface, and the group of points related to the retina may be approximated by a plane. Thus, the eye structure model may be a combination of approximate surfaces corresponding to the surfaces of the components of the eye.

The reconstruction unit 5 may be configured to determine the direction of the optical axis of the eye in the direction of a line in which centers of approximate spherical surfaces corresponding to the structural surfaces of the eye are located.

The eye adaptation distance determining unit 6 determines an adaptation distance of the eye based on a structural model inside the eye. In more detail with reference to FIGS. 7 and 8, the adaptation distance S1 of the eye is the distances S ₂ ^{, d between the structural surfaces of the eye and the curvatures R1 -1} and R2 ^-1 of the structural surfaces. , R3 ^-1 ), and the distances and curvatures may be obtained based on the eye structure model generated by the reconstruction unit 5. The adaptation distance S ₁ may be determined from a combination of the following equations.

here,

Equation 1 is a thin lens equation (effective optical layout equation),

Equation 2 is the eye optical system equation,

f is the effective optical placement focal length,

R ₁ is the radius of curvature of the cornea,

R ₂ is the radius of curvature of the front of the lens,

R ₃ is the radius of curvature of the back of the lens,

d is the thickness of the lens,

S ₁ is the (to be calculated) adaptation distance,

S ₂ is the distance between the lens and retina,

n ₁ is the refractive index of the eye medium of the vitreous body,

n ₂ is the refractive index of the lens medium.

Among the above-described values, values of R ₁ , R ₂ , R ₃ , d and S ₂ are determined based on a structural model inside the eye (see FIG. 5 ), _{and values of n 1} and n ₂ are predetermined, The value of S ₁ is the value to be determined.

Therefore, the proposed device provides an accurate determination of the adaptation distance of the eye based on a structural model inside the eye.

Specific embodiments in which the method of generating the interference signals is different and the method of generating a plurality of frequency modulated laser beams in different directions will be described below.

Embodiment 1

According to the first embodiment shown in FIG. 9, the interferometer of the apparatus for determining the adaptive distance of the eye is an SMI interferometer, for example, a vertical-cavity surface-emitting-laser (VCSEL). ), a laser array 11, a laser array driver 12, and an optical system.

The laser array driver 12 provides a modulation of the laser pumping current at the same time to the lasers in the laser array 11, e.g., to one laser, to a group of lasers, or to all lasers in the array, The modulated control signal is selectively supplied. The number of lasers operating simultaneously is limited to the maximum permissible laser emission power that is safe for the eyes. Each laser in the array has a different specific beam direction. This beam direction depends and is known in advance on the position of the laser in the laser array 11 relative to the other components of the eye's adaptive distance determination device involved in forming the beam direction.

The optical system is involved in shaping the direction of the beams, transmits light to the user's eye, and may include, for example, one or more lenses 13 and a dichroic mirror 14. The dichroic mirror 14 is just one example of a means for transmitting light to the user's eyes. Instead of the dichroic mirror 14, a waveguide, for example, may be used.

In the detailed description, the term beam direction is used at the end of the path of the laser beam before it is incident on the reflective surfaces of the eye, that is, in the part of the path of the beam after exiting from the optical system of the interferometer, the head mounted display and It can be understood as the position in space of the axis of the laser beam relative to the associated coordinate system.

According to this embodiment, the interferometer generates a self-mixed interference signal. The beam emitted by a specific laser is transmitted to the eye through the elements of the optical system, is reflected by the structural surfaces of the eye, and re-enters the cavity of the laser that emitted the laser beam to affect the beam generation mode (i.e. , A self-mixing effect occurs). This effect is detected by measuring the laser bias voltage at the driver 12 side or by measuring the oscillation of the laser output using a photodiode (not shown in the drawing) mounted in the laser package. The corresponding signal obtained from the driver or photodiode is the self-mixed interference signal.

Thus, the laser array 11 is used to generate a plurality of beams and the SMI effect is used to generate an interference signal. This embodiment is characterized by a minimization of the number of elements, a simple configuration and a low cost.

In this and other embodiments, the functions of generating a plurality of beams and delivering light to the user's eyes and elements (e.g., optical and optical-mechanical scanning systems) are conditionally related to the interferometer, but if necessary, You can think of it separately.

Example 2

According to the second embodiment shown in FIG. 10, the interferometer of the apparatus for determining the adaptive distance of the eye includes a laser array 11, a laser array driver 12, a detector 15, a beam splitter 16, and a reference mirror 17. , And an optical system.

The laser array 11, the laser array driver 12, and the optical system are the same as those described in the first embodiment.

The second embodiment differs from the first embodiment in the manner of generating an interference signal. The beam emitted by a particular laser in the array 11 is split into two beams by a beam splitter 16 (partially reflecting mirror), one of which is reflected from the reference mirror 17 and the other is the user. It is transmitted to the eye of the eye and reflected from the reflective surfaces of the eye. The two beams return to the beam splitter 16 and are sent to the detector 15, where the beams interfere to form an interfering signal.

This embodiment has more components, is less compact and more expensive, but provides a better signal-to-noise ratio with the same laser power.

Embodiment 3

According to the third embodiment shown in Fig. 11, the interferometer of the apparatus for determining the adaptive distance of the eye is a magnetic mixing interferometer and includes a single laser 18, a laser driver, an optical-mechanical scanning system, and an optical system.

Since the optical system of this embodiment corresponds to the optical system of the previous embodiments, a description thereof will be omitted.

The generation of the interference signal is performed using a magnetic mixing effect similar to that of the first embodiment, that is, by measuring the laser bias voltage at the driver side or by measuring the oscillation of the laser output using a photodiode mounted in the laser package.

The optical-mechanical scanning system provides a change in laser beam direction and can be implemented using any optical deflection technique, such as rotating mirrors, MEMS mirrors, movable lenses, acoustic-optical deflectors, and the like. In the embodiment schematically shown in FIG. 11, the optical-mechanical scanning system is a movable mirror 19.

The optical-mechanical scanning system, for example, is a system of movable mirrors that are driven by a motor to provide laser beam scanning, a mirror position sensor, and the state of the scanning system at each moment by controlling the motor and reading the sensor. It may include a controller that provides the generation (beam direction information) of a signal to build and determine the laser beam position at each instant.

In this embodiment where an optical-mechanical scanning system is used, since a single laser with a beam moving continuously in space is used, a specific laser beam is considered within a small time interval (e.g., within the modulation period of the laser). It should be understood as a laser beam.

Embodiment 4

According to the fourth embodiment shown in Fig. 12, the interferometer of the apparatus for determining the adaptive distance of the eye is a single laser 18, a laser driver, an optical-mechanical scanning system, a detector 15, a beam splitter 16, and a reference mirror ( 17), and a two-arm interferometer including an optical system.

The fourth embodiment is different from the third embodiment and is similar to the second embodiment in the manner of generating an interference signal.

The proposed eye adaptive distance determination device can be used as a component of a head mounted display device having a variable focal length. For example, referring to FIG. 13, the head mounted display device 20 having a variable focal length includes the aforementioned apparatus for determining an adaptive distance of the eye and a rendering system 21 having a variable focal length. The rendering system 21 having a variable focal length is connected to the apparatus for determining an adaptive distance of the eye and receives a signal regarding the adaptive distance of the eye determined by the apparatus for determining the adaptive distance of the eye. At the same time, the rendering system 21 is configured to adjust the focal length based on the determined adaptation distance. The algorithm for determining the focal length of the visualization system based on the determined adaptation distance varies depending on the application. For example, the rendering system 21 may adjust the focal length so that the displayed virtual object is always focused on the user's eyes. For example, the rendering system 21 may adjust the focal length so that the virtual object and the real object coincide by minimizing the distance g between the adaptation distance of the user's eyes and the focal plane of the virtual object. Accordingly, the focal length of the head mounted display can be more accurately adjusted based on the adaptation distance of the user's eyes.

The above-described apparatus and method for measuring eye adaptive distance for a head mounted display, and a head mounted display have been described with reference to the embodiments shown in the drawings, but these are only exemplary, and those of ordinary skill in the art It will be appreciated that various modifications and other equivalent embodiments are possible. Therefore, the disclosed embodiments should be considered from an illustrative point of view rather than a limiting point of view. The scope of the rights is indicated in the claims rather than the above description, and all differences within the scope equivalent thereto should be construed as being included in the scope of the rights.

1.....laser interferometer 2.....signal processing unit
3.....distance determination unit 4.....point coordinate determination unit
5.....reconstruction part 6.....adaptation distance determination part of eyes
11.....laser array 12.....laser array driver
15.....detector 16.....beam splitter
17.....reference mirror 18.....single laser
20.....head mounted display unit 21.....rendering system

Claims (15)

An interferometer that generates a plurality of frequency-modulated laser beams in different directions and generates a plurality of interference signals from the laser beams reflected from the reflective surfaces of the eye among the plurality of laser beams;
A signal processor for generating a signal spectrum using each of a plurality of interference signals;
A distance determining unit that analyzes the signal spectrum and determines a distance to a reflective surface of the eye for each laser beam;
A point coordinate determining unit for determining coordinates of points on each reflective surface of the eye for each laser beam based on the determined distance to the reflective surfaces of the eye and information about the direction of each laser beam;
A reconstruction unit that generates an eye internal structure model based on the determined coordinates of points on the reflective surface of the eye; And
And an eye adaptation distance determining unit configured to determine an eye adaptation distance based on the eye internal structure model. The method of claim 1,
Each signal spectrum generated by the signal processing unit for the laser beam incident on the retina of the eye has first to fourth peaks in the frequency domain,
The first peak corresponds to the surface of the cornea, the second peak corresponds to the front surface of the lens, the third peak corresponds to the back surface of the lens, and the fourth peak corresponds to the surface of the retina. The method of claim 2,
The distance determining unit calculates distances to reflective surfaces of the eyes reflecting each laser beam by extracting peaks according to the optical path distance of each laser beam from the first to fourth peaks in the frequency domain of each signal spectrum. Device for determining the adaptive distance of the eye The method of claim 2,
The plurality of laser beams are incident on different points on the reflective surfaces of the eye, and the signal processing unit generates a signal spectrum for different points on the reflective surfaces of the eye using the plurality of laser beams. Adaptive distance determination device. The method of claim 1,
The reconstruction unit approximates the points corresponding to the surface of the cornea, the front surface of the lens, and the rear surface of the lens with a spherical surface, so that the radius of curvature of the cornea, the radius of curvature of the front of the lens, the radius of curvature of the rear of the lens, the thickness of the lens, and between the lens and the retina An eye adaptation distance determination device that calculates a distance and determines an adaptation distance of the eye based on this. The method of claim 5,
The reconstruction unit determines the optical axis direction of the eye in the direction of the line where the centers of the approximate spherical surfaces are located. The method of claim 1,
The signal processing unit, the distance determining unit, the point coordinate determining unit, the reconstruction unit, and the eye adaptive distance determining unit determine the adaptive distance of the eye implemented by one software, one semiconductor chip, or one electronic circuit. Device. The method of claim 1,
The interferometer is a magnetic mixing interferometer including a laser array including a plurality of lasers and a laser array driver for supplying a frequency modulated control signal to each laser of the laser array,
The interference signal is a laser magnetic mixing signal adaptive distance determination device of the eye. The method of claim 1,
The interferometer is a magnetic mixing interferometer including a laser, a laser driver for supplying a frequency modulated control signal to the laser, and an optical-mechanical scanning system,
The interference signal is a laser magnetic mixing signal adaptive distance determination device of the eye. The method of claim 9,
The interferometer is an apparatus for determining an adaptive distance of the eye, configured such that the laser beam reflected from the reflective surfaces of the eye re-enters the cavity of the laser emitting the laser beam. The method of claim 1,
The interferometer includes a laser array including a plurality of lasers, a laser array driver for supplying a frequency modulated control signal to each laser of the laser array, a detector, a beam splitter, and a reference mirror,
The apparatus for determining an adaptive distance of the eye, wherein the interference signal is a signal generated by the detector. The method of claim 1,
The interferometer comprises a laser, a laser driver for supplying a frequency modulated control signal to the laser, a detector, a beam splitter, a reference mirror, and an optical-mechanical scanning system. The method of claim 12,
The beam splitter divides the laser beam emitted by the laser into a first beam and a second beam, the first beam is reflected from the reference mirror and the second beam is reflected from the reflective surfaces of the eye, and the reflected first beam An apparatus for determining an adaptive distance of an eye in which the beam and the second beam form an interference signal in the detector. Generating a plurality of laser beams frequency modulated in different directions, the beam direction information corresponding to each beam direction, and at least some of the plurality of laser beams are incident on reflective surfaces of the inner structure of the eye;
Generating an interference signal for each laser beam of the plurality of laser beams;
Generating a signal spectrum for each interfering signal from among the plurality of interfering signals;
Analyzing a signal spectrum to determine a distance to a reflective surface for each laser beam among the plurality of laser beams;
Determining coordinates of points of the eye surface for each beam based on the determined distance to reflective surfaces and beam direction information, within a coordinate system associated with the head mounted display;
Generating a model of the internal structure of the eye based on the determined coordinates of points on the eye surface; And
Determining an adaptation distance of the eye based on the internal structure model of the eye. An apparatus for determining an adaptive distance of an eye according to any one of claims 1 to 13 and a rendering system having an adjustable focal length,
The rendering system having the adjustable focal length automatically adjusts the focal length based on the eye adaptation distance obtained from the eye adaptation distance determination device.

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