Eyeball tilt position detection device, display device, and optometry device

Abstract

The objective is to provide an eyeball tilt position detection device that is resistant to vibration and external impacts. [Solution] An apparatus for detecting the tilt position of an eyeball according to one aspect of the disclosed technology, characterized by comprising: a light source array having a plurality of light-emitting units that emit directional light; and an optical position detection element for detecting the optical position of the reflected light from the eyeball.

Description

Technical Field

[0006] , , , , , ,

[0001] The present invention relates to an eye tilt position detection device, a display device, and an ophthalmic examination device.

Background Art

[0002] In recent years, technologies and products related to virtual reality (VR) and augmented reality (AR) have attracted attention. In particular, AR technology is expected to be applied to industrial fields as a means of displaying digital information in the real space. In view of the fact that "people" who utilize AR technology obtain most of their cognitive information through vision, a glasses-type video display device that can be used in an action (work) environment has been developed.

[0003] As such a glasses-type video display device, a glasses-type video display device of a retinal projection method that directly projects an image onto the retina of a "person" using a laser is known. According to the retinal projection method, by superimposing a focus-free image on visual information, digital information can be displayed on the retina in a state where the viewpoint is placed outside the body and recognized by the "person".

[0004] By the way, in a glasses-type video display device of a retinal projection method using a laser, in an action (work) environment involving eye movement due to limitations in the size of the cornea and pupil, laser scattering occurs at the outer periphery of the cornea and pupil, etc., and there may be a case where a predetermined image cannot be projected at a predetermined position.

[0005] In order to detect the position of the cornea and feedback it to the image projection position, etc., an eye tracking technology including a MEMS (Micro Electro Mechanical Systems) mirror that scans a laser on the eye, a photodetector for detecting the intensity of reflected light, and an electronic circuit that estimates the corneal position on the eye from the detected intensity has been disclosed (see, for example, Patent Document 1 and Non-Patent Document 1).

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the technologies described in Patent Document 1 and Non-Patent Document 1 have movable structures such as MEMS mirrors, which can lead to a decrease in the accuracy of detecting the tilt position of the eyeball, such as the corneal position, due to vibrations or external shocks.

[0007] The present invention has been made in view of the above points, and aims to provide an eyeball tilt position detection device that is resistant to vibration and external shocks. [Means for solving the problem]

[0008] An apparatus for detecting the tilt position of an eyeball according to one aspect of the disclosed technology, characterized by comprising: a light source array having a plurality of light-emitting units that emit directional light; and an optical position detection element for detecting the optical position of the reflected light from the eyeball. [Effects of the Invention]

[0009] According to embodiments of the present invention, it is possible to provide an eyeball tilt position detection device that is resistant to vibration and external shocks. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example of the configuration of the pupil position detection device according to the first embodiment. [Figure 2] This figure illustrates an example of the operation of pupil position detection by the pupil position detection device of the first embodiment. [Figure 3] This diagram shows an example of the hardware configuration of the processing unit of the first embodiment, using functional blocks. [Figure 4] This diagram shows an example of the components of the processing unit of the first embodiment, represented by a functional block. [Figure 5] This flowchart shows an example of processing by the pupil position calculation unit of the first embodiment. [Figure 6] This figure illustrates a numerical simulation performed to verify the principle of pupil position detection in the pupil position detection device of the first embodiment. [Figure 7]This figure shows an example of the configuration of the pupil position detection device according to the second embodiment. [Figure 8] This figure shows an example of a light deflection means according to the third embodiment. [Figure 9] This figure shows an example of a configuration in which the light distribution module of the third embodiment is arranged on a spectacle-type support. [Figure 10] This figure shows an example of the configuration of the display device according to the fourth embodiment. [Figure 11] This is a diagram showing the configuration of the eye-tracking device described in Patent Document 1. [Modes for carrying out the invention]

[0011] The embodiments for carrying out the invention will be described below with reference to the drawings. In each drawing, the same reference numerals are used for identical components, and redundant explanations may be omitted.

[0012] In the embodiment, the "tilt position of the eyeball" refers to the position of the pupil or cornea of ​​the eyeball, etc. Below, we will describe an example in which the "tilt position of the eyeball" is the position of the pupil and the "tilt position detection device of the eyeball" is the "pupil position detection device". Hereafter, the "tilt position detection device of the eyeball" will be simply referred to as the "pupil position detection device". Furthermore, we will describe an example in which the "pupil position detection device" is mounted on a spectacle-type support.

[0013] In this embodiment, the pupil position detection device for the right eye of a "person" is described as an example, but the same applies to the left eye. Furthermore, it is possible to use two pupil position detection devices and apply them to both eyes.

[0014] [First Embodiment] Figure 1 shows an example of the configuration of the pupil position detection device according to this embodiment. The arrows shown in the figure indicate the X, Y, and Z directions.

[0015] In FIG. 1, the pupil position detection device 10 includes a light source array 1, a lens 2, a planar mirror 3, a light position detection element 4, and a processing unit 100. The light source array 1 and the lens 2 are provided on the spectacle frame 21 of the spectacle-type support 20, and the planar mirror 3 and the light position detection element 4 are provided on the spectacle lens 22 of the spectacle-type support 20. The processing unit 100 includes a light emission control unit 110 and a pupil position calculation unit 120.

[0016] The light source array 1 has a plurality of light emitting parts two-dimensionally arranged in a plane. Note that the "plurality of light emitting parts" is synonymous with "plurality of light emitting points" or "plurality of light emitting elements".

[0017] Each light emitting part emits a laser beam with directivity upward in the figure. The light source array 1 is, for example, a VCSEL (Vertical Cavity Surface Emitting LASER) with the upward direction in the figure as the emission direction. However, it is not limited to this, and for example, a plurality of LDs (Laser Diodes) that emit laser beams with directivity may be two-dimensionally arranged in a plane to form the light source array 1.

[0018] The wavelength of the light emitted from the light source array 1 is preferably the wavelength of near-infrared light, which is invisible light, so as not to interfere with the visual recognition of the "person" whose pupil position is to be detected. However, it is not limited to this, and visible light may also be used.

[0019] The lens 2 deflects the light emitted from the light source array 1 in a predetermined direction. The lens 2 is, for example, a convex lens, and deflects the passing light in a predetermined direction by refracting the passing light. The light source array 1 and the lens 2 are fixed and integrated on the same substrate 5a to form a light distribution module 5. The light distribution module 5 is fixed to a stable stationary support such as the spectacle frame 21 provided in the spectacle-type support 20.

[0020] Light deflected by lens 2 is reflected towards the eyeball 30 by plane mirror 3. Planar mirror 3 is fixed to the spectacle lens 22 of spectacle-type support 20. Due to the deflection by lens 2 and the reflection by plane mirror 3, light from light source array 1 is incident at a predetermined angle on the center of the pupil 31 of the eyeball 30 when normal vision is achieved. Lens 2 and plane mirror 3 have the function of deflecting light from light source array 1 and causing it to incident on the eyeball 30. Lens 2 and plane mirror 3 are an example of "light deflection means that causes light to incident on the eyeball at a predetermined angle".

[0021] Furthermore, the light deflection means is not limited to the lens 2 and the planar mirror 3. Any component or any combination of components may be used as long as it is possible to direct light from the light source array 1 onto the eyeball at a predetermined angle. However, by using one or more of the following as the light deflection means in addition to the convex lens described above: a microlens array, a concave curved mirror, a hologram diffraction element, a prism array, or a diffraction grating, effects such as expanding the pupil detection range, miniaturizing the device, and reducing the assembly load of the pupil position detection device 10 can be obtained. Other examples of such light deflection means will be described in detail in the third embodiment.

[0022] The pupil surface (corneal surface) is a transparent body containing water and typically has a reflectivity of about 2-4%. Light incident near the pupil 31 is reflected at the reflection point P on the pupil surface (corneal surface) of the eyeball 30, and the reflected light is incident on the optical position detection element 4. The optical position detection element 4 is, for example, a 2D PSD (Position Sensitive Detector).

[0023] Furthermore, PSD detects the direction of the normal vector of the reflection point, i.e., its 3D shape. The pupil center position is "estimated" by the correspondence between the detected 3D shape and the eyeball model.

[0024] The two-dimensional PSD detects current values ​​corresponding to the distance to the electrodes in two orthogonal directions within the light-receiving surface, based on the position of the incident light on the light-receiving surface. It then calculates and outputs the position of the incident light from the ratio of the current values ​​in the two directions. The two-dimensional PSD can detect the position of the incident light independently of the light intensity of the incident light. Therefore, even if there is a difference in the amount of reflected light due to the reflection position on the eyeball 30, highly sensitive position detection is possible without being affected by the difference in the amount of reflected light. Furthermore, compared to cases where an image sensor such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal-Oxide-Semiconductor) is used as the optical position detection element 4, it does not require complex image processing for position detection, thus reducing the processing load.

[0025] However, the optical position detection element 4 is not limited to a two-dimensional PSD. The position of the incident light in the XY plane may be detected by arranging one-dimensional PSDs capable of detecting the position of incident light in the X direction in the Y direction, or by arranging one-dimensional PSDs capable of detecting the position of incident light in the Y direction in the X direction. In this case, since one-dimensional PSDs are less expensive than two-dimensional PSDs, etc., it is possible to reduce the cost of the pupil position detection device 10.

[0026] Alternatively, an image sensor such as a CCD or CMOS may be used as the optical position detection element 4, and the position of the light may be detected or estimated by image processing based on the spatial intensity distribution of light incident on the imaging surface.

[0027] Furthermore, the position of the light incident on the light-receiving surface of the light position detection element 4 is an example of "the position of the light reflected from the eyeball."

[0028] The light emission control unit 110 of the processing unit 100 is electrically connected to the light source array 1 and transmits control signals to the light source array 1. The light emission control unit 110 controls which light-emitting units in the light source array 1 emit light and the timing of the light emission using the control signals. In other words, the timing of light emission between multiple light-emitting units changes at predetermined intervals. This allows the light emission control unit 110 to change the angle of incidence of light to the eyeball 30 over time. The processing unit 100 is an example of "processing means for performing detection processing of the tilt position of the eyeball," and the light emission control unit 110 is an example of "light emission control means."

[0029] The pupil position calculation unit 120 is electrically connected to the light position detection element 4 and receives a detection signal output by the light position detection element 4 according to the position of the light incident on the light-receiving surface of the light position detection element 4. Based on the detection signal, the pupil position calculation unit 120 calculates the position of the pupil 31. The pupil position calculation unit 120 is an example of a "position calculation means".

[0030] When the direction of reflected light from the eyeball 30 changes due to eye movements such as rotation of the eyeball 30, the reflected light may move away from the light-receiving surface of the optical position detection element 4. To prevent this, the light emission control unit 110 sequentially or selectively changes the light-emitting units emitted by the light source array 1. When the light-emitting unit changes, the position of the light emission within the plane in which the light-emitting units are arranged in the light source array 1 changes, and the angle of incidence of the light incident on the eyeball 30 via the lens 2 and the plane mirror 3 changes. By changing the angle of incidence to the eyeball 30, the position of the light reflected by the eyeball 30 and incident on the light-receiving surface of the optical position detection element 4 can be changed. Therefore, by changing the light-emitting units emitted by the light source array 1 in accordance with the eye movements of the eyeball 30, it is possible to prevent the reflected light from the eyeball 30 from moving away from the light-receiving surface of the optical position detection element 4.

[0031] The signal detected by the light position detection element 4 indicates a change in the position of light reflection on the eyeball 30. The pupil position calculation unit 120 calculates the rotation angle of the eyeball 30 and the pupil position based on the detection signal from the light position detection element 4.

[0032] Figure 2 illustrates an example of the operation of pupil position detection by the pupil position detection device 10. Figure 2 shows the behavior of light emitted from two light-emitting parts located at different positions in the light source array 1. Light 1a from one light-emitting part is represented by a dotted line, and light 1b from the other light-emitting part is represented by a dashed line. (a) shows the eyeball 30 in emmetropia, i.e., when the eyeball 30 is facing forward, and (b) shows the eyeball 30 in rotation.

[0033] In (a), the light 1a shown by the dotted line is reflected by the eyeball 30 and incident near the center of the light-receiving surface of the light position detection element 4. Therefore, the light position detection element 4 can detect the change in the incident position of light 1a on the light-receiving surface in accordance with the rotation of the eyeball 30. The pupil position calculation unit 120 can calculate the position of the pupil 31 based on the detection signal of the light position detection element 4. On the other hand, the light 1b shown by the dashed line is reflected by the eyeball 30 and does not incident on the light-receiving surface of the light position detection element 4. Therefore, light 1b does not contribute to the detection signal of the light position detection element 4. For this reason, the pupil position calculation unit 120 cannot calculate the position of the pupil 31.

[0034] On the other hand, as shown in (b), when the eyeball 30 rotates significantly relative to (a), the light 1a that was incident on the light-receiving surface of the light position detection element 4 during normal vision moves away from the light-receiving surface of the light position detection element 4 and no longer contributes to the detection signal of the light position detection element 4. Therefore, the pupil position calculation unit 120 cannot calculate the position of the pupil 31. Conversely, the light 1b is incident near the center of the light-receiving surface of the light position detection element 4. Therefore, the light position detection element 4 can detect the change in the incident position of the light 1b on the light-receiving surface in accordance with the rotation of the eyeball 30. Based on the detection signal of the light position detection element 4, the pupil position calculation unit 120 can calculate the position of the pupil 31.

[0035] Thus, with light from a single light-emitting unit, the eye movement of the eyeball 30 can only be detected within a limited angular range. In contrast, in this embodiment, by changing the light-emitting unit of the light source array 1, the angle of incidence to the eyeball 30 is changed, thereby expanding the detection range of the eye movement of the eyeball 30. This makes it possible to expand the detection range of the pupil 31 position.

[0036] The changes in the light-emitting portion of the light source array 1 are performed in a time series according to the eye movements of the eyeball 30, based on control signals from the light-emitting control unit 110. By controlling the light-emitting portion in accordance with (tracking) the eye movements of the eyeball 30, it is possible to improve light utilization efficiency and shorten the estimation time. However, it is not always necessary to "respond to eye movements". For example, the position of the light-emitting portion can be raster-scanned at regular time intervals independently of eye movements to obtain the coarse movement position of the eyeball.

[0037] In Figure 2, for the sake of simplicity, only light emitted from two light-emitting units is shown as an example. However, in this embodiment, many more light-emitting units of the light source array 1 can be utilized in response to the eye movements of the eyeball 30. In this case, the number and position of the light-emitting units of the light source array 1 are optimized so that the position of the pupil 31 is properly detected, according to the size of the light-receiving surface of the light position detection element 4 and the size of the eyeball.

[0038] Figure 3 is a diagram showing an example of the hardware configuration of the processing unit 100 in this embodiment, using functional blocks.

[0039] The processing unit 100 includes a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, and an input / output interface (I / F) 104. These are interconnected via a system bus 105.

[0040] The CPU 101 comprehensively controls the operation of the processing unit 100. The CPU 101 also performs a process to calculate the position of the pupil 31 based on the detection signal from the optical position detection element 4.

[0041] The CPU 101 executes the above-mentioned control and processing by running programs stored in ROM 102 or the like, using RAM 103 as a work area, thereby realizing the various functions described later. Some or all of the functions of the CPU 101 may be implemented by wired logic hardware such as ASIC (application-specific integrated circuit) or FPGA (field-programmable gate array).

[0042] The Input / Output I / F104 is an interface for connecting to external devices such as PCs (Personal Computers) and video equipment.

[0043] Figure 4 is a diagram showing an example of the components of the processing unit 100 of this embodiment in terms of functional blocks. Note that each functional block shown in Figure 4 is conceptual and does not necessarily have to be physically configured as shown. All or part of each functional block can be functionally or physically distributed and combined in any unit. Each processing function performed by each functional block can be implemented, in whole or in part, by a program executed by the CPU 101 described above, or by hardware using wired logic.

[0044] As described above, the processing unit 100 includes a light emission control unit 110 and a pupil position calculation unit 120. The functions of the light emission control unit 110 are as described above. The pupil position calculation unit 120 includes a detection signal receiving unit 121, an eyeball rotation angle estimation unit 122, and a pupil center position calculation unit 123.

[0045] The detection signal receiving unit 121 receives the detection signal output by the optical position detection element 4 and outputs it to the eye rotation angle estimation unit 122.

[0046] The eyeball rotation angle estimation unit 122 estimates the rotation angle of the eyeball 30 based on the detection signal of the optical position detection element 4, and outputs the estimated rotation angle to the pupil center position calculation unit 123.

[0047] The pupil center position calculation unit 123 calculates the center position of the pupil 31 based on the rotation angle of the eyeball 30.

[0048] Figure 5 is a flowchart showing an example of processing by the pupil position calculation unit 120 of this embodiment.

[0049] Prior to step S61, as preliminary preparation for calculating the pupil position, the angle at which light emitted from the light source array 1 enters the eyeball 30 is designed, and the formula for calculating the rotation angle of the eyeball 30 is determined.

[0050] The formula for calculating the rotation angle of the eyeball 30 is a linear or quadratic function. However, it is not limited to these. Any formula that determines the rotation angle from the designed light ray incidence angle and the landing position of the reflected light ray on the light position detection element is acceptable, regardless of its form. As a simple approximation, a quadratic function formula is used in the simulation.

[0051] A model of the surface shape of the eyeball 30 is used to design the angle at which light enters the eyeball 30. Common models of the eyeball surface shape, such as the simplified eye model, have been known for a long time (see, for example, "Optical Mechanism of the Eye," Precision Machinery 27-11, 1961).

[0052] The planar mirror 3 (see Figures 1 and 2) is positioned at the focal point of the light emitted from the light source array 1. The light reflected by the planar mirror 3 enters the eyeball 30. The light entering the eyeball 30 is reflected by the eyeball 30, which has been rotated by a predetermined angle, and propagates toward the optical position detection element 4. The angle at which the light enters the eyeball 30 is calculated and designed in advance using ray tracing calculations, etc., so that this propagating light enters the center position of the light-receiving surface of the optical position detection element 4.

[0053] The incident position of light on the light-receiving surface of the optical position detection element 4 can be theoretically analyzed based on the incident angle of light on the eyeball 30, the reflection position of light on the eyeball 30, and the inclination of the tangent surface on the eyeball 30. From the solution of such theoretical analysis, an inverse calculation formula (approximation formula) is determined to estimate the rotation angle of the eyeball 30 using polynomial approximation.

[0054] The above describes the preliminary preparations performed for pupil position calculation prior to step S61 in Figure 5. The angle of light incident on the eyeball 30 and the inverse calculation formula for estimating the rotation angle of the eyeball 30 are stored in the memory of the processing unit 100, such as the ROM 102, and are referenced and used in light emission control by the light emission control unit 110 and in pupil position calculation by the pupil position calculation unit 120.

[0055] In Figure 5, first, the light emission control unit 110 causes at least one of the light-emitting parts of the light source array 1 to emit light at a predetermined timing according to the pre-designed angle of incidence of light. The light position detection element 4 detects the position where the light emitted from the light source array 1 and reflected by the eyeball 30 enters the light-receiving surface of the light position detection element 4, and outputs this to the processing unit 100. In the processing unit 100, the detection signal receiving unit 121 of the pupil position calculation unit 120 receives the detection signal from the light position detection element 4 (step S61). The detection signal receiving unit 121 outputs the detection signal to the eyeball rotation angle estimation unit 122.

[0056] Next, the eye rotation angle estimation unit 122 substitutes the input detection signal (position data) into the inverse calculation formula described above to calculate the eye rotation angle (step S63). The eye rotation angle estimation unit 122 outputs the calculated eye rotation angle to the pupil center position calculation unit 123.

[0057] The pupil center position calculation unit 123 calculates the pupil center position using a model of the eyeball surface shape based on the input eyeball rotation angle (step S65).

[0058] In this way, the position of the pupil 31 in the eyeball 30 can be detected.

[0059] Figure 6 illustrates a numerical simulation performed to verify the principle of pupil position detection in the pupil position detection device 10 of this embodiment.

[0060] In this numerical simulation, we assume that a planar mirror 3 and an optical position detection element 4 are positioned in a plane 10 mm away from the eyeball 30 in the -Z axis direction, as shown in Figure 1. The reference angle (θx, θy) of the eyeball 30 is defined as the value obtained when the rotation angle of the eyeball 30 is changed in 5 increments in the X direction (5 points) and the Y direction (3 points).

[0061] In Figure 6, the horizontal axis represents the change in the eye rotation angle in the X direction, and the vertical axis represents the change in the eye rotation angle in the Y direction. The values ​​are based on the angle of incidence (angle change (0,0)) for each of the five points in the X direction and three points in the Y direction, each in 5° increments.

[0062] In the numerical simulation, the emission angle (reflection angle at the plane mirror 3) at the position of the plane mirror 3, where the light reflected by the eyeball 30 and incident on the center of the light position detection element 4 is located, was numerically calculated for each reference angle of the eyeball 30. The center of the light position detection element 4 is represented as coordinate (0,0).

[0063] Furthermore, the difference (Δθx, Δθy) between the light at each emission angle and the reference angle (θx, θy) of the eyeball 30 was expressed as a quadratic function using an inverse calculation formula that estimates the incident position (x, y) on the light-receiving surface of the light position detection element 4, and its coefficients were numerically calculated using a Taylor expansion method.

[0064] Figure 6(a) is a graph showing the estimated rotation angle of the eyeball 30 when the reference angle is (θx,θy)=(0°,0°), i.e., when the normal viewing state is used as the reference angle. In graph (a), the grid points represent the actual rotation angle of the eyeball 30, and the dots represent the estimated position. When the rotation angle of the eyeball 30 is small, a good agreement is obtained. In this case, the error is limited to a maximum of about 0.1° within the range of |Δθx|≦2.5°. Here, the value of 2.5° is half the value obtained by dividing the reference angle into 5° increments, and represents the condition that no region where light is not detected occurs. Furthermore, since a configuration in which the plane mirror 3 and the optical position detection element 4 are arranged in the X direction in a plane is assumed, the error in the Y direction is smaller than that in the X direction.

[0065] Figure 6(b) shows the results when the reference angle is (θx,θy)=(10°,5°), that is, when the position of the pupil 31 is to the upper right of the normal viewing position. The rotation angle of the eyeball 30 is estimated within the same error range as the result in (a).

[0066] The numerical simulation results above show an estimated value of the rotation angle of the eyeball 30. The rotation angle of the eyeball 30 can be defined as the angle formed by the straight line connecting the center of the eyeball 30, i.e., the center of rotation, and the center of the cornea, with respect to the Z-axis, which is the direction of normal vision. Therefore, the position of the pupil 31 can be calculated as a coordinate that is separated from the center of the eyeball 30 by the distance between the center of the eyeball 30 and the center of the cornea, in the direction of the rotation angle of the eyeball 30. Note that the distance from the center of the eyeball 30 to the center of the cornea is given in advance by the eyeball model.

[0067] As shown above, numerical simulations have verified that the calculation process of the pupil position calculation unit 120, as shown in Figure 5, can calculate the position of the pupil 31 with sufficient accuracy.

[0068] As described above, this embodiment includes a light source array 1 having a plurality of light-emitting units that emit directional light, and a detection element that detects the position of the reflected light from the light-emitting units on the eyeball. By changing the light-emitting units of the light source array 1 at predetermined timings, the angle of incidence to the eyeball 30 is changed, and the detection range of the pupil 31 position is expanded. In this embodiment, such detection of the pupil position is performed using a non-mechanical configuration without using a movable structure such as a MEMS mirror. This makes it possible to detect the pupil position in a way that is resistant to vibration and external shocks. In other words, this embodiment provides an eyeball tilt position detection device, such as pupil position, that is resistant to vibration and external shocks.

[0069] According to this embodiment, since there are no movable parts such as MEMS mirrors, it is possible to suppress the amount of light reflected by the eyeball that does not reach the photodetector, thereby improving light utilization efficiency. Furthermore, the influence of noise such as ambient light can be suppressed. In addition, since there is no dynamic deformation like that of MEMS mirrors, the accuracy of pupil position detection can be ensured without complicated adjustments.

[0070] According to this embodiment, a two-dimensional or one-dimensional PSD is used as the optical position detection element 4 to detect the incident position of the reflected light of the light irradiated onto the eyeball on the light-receiving surface of the optical position detection element 4. Since the position of the incident light is detected independently of the light intensity of the incident light, even if there is a difference in the amount of reflected light due to the reflection position of the light on the eyeball 30, the position of the incident light can be detected with high sensitivity without being affected by the difference in the amount of reflected light. As a result, the tilt position of the eyeball, such as the pupil, can be detected with high accuracy.

[0071] Furthermore, since an image sensor such as a CCD is not used to detect the position of incident light, the processing load such as image processing can be reduced. In addition, high speed and real-time performance of pupil position detection can be ensured without using expensive configurations such as high-speed arithmetic units and large-capacity memory. When a one-dimensional PSD is used as the optical position detection element 4, an eyeball tilt position detection device, such as pupil position, can be realized at low cost.

[0072] According to this embodiment, the light source array 1 and the lens 2 are integrated by placing them on the same substrate. This makes it possible to miniaturize the eyeball tilt position detection device and reduce the assembly load. Alternatively, the above effects can be achieved by integrating the first substrate on which the light source array 1 is placed and the second substrate on which the lens 2 is placed by bringing them into contact.

[0073] According to this embodiment, since a VCSEL is used in the light source array 1, the angle of incidence to the eyeball 30 can be changed by changing the light-emitting part of the VCSEL, thereby expanding the detection range of the pupil 31.

[0074] Although the above example shows a configuration with one light source array 1, a configuration with multiple light source arrays is also possible. This further expands the range in which the incident angle to the eyeball 30 can be changed, and further expands the detection range of the pupil 31 position.

[0075] [Second Embodiment] Next, the pupil position detection device of the second embodiment will be described with reference to Figure 7. Note that in the second embodiment, descriptions of components identical to those described in the previously described embodiments may be omitted.

[0076] Figure 7 shows an example of the configuration of the pupil position detection device 10b of this embodiment.

[0077] The pupil position detection device 10b has an optical position detection element 4 positioned in the direction of the reverse reflection of light incident on the eyeball 30 via the light source array 1 and lens 2. In other words, the optical position detection element 4 is positioned on the same side of the eyeball 30 as the light source array 1.

[0078] The above arrangement is achieved by changing the incident position on the eyeball 30 and the position of the reflection point P compared to the first embodiment.

[0079] According to this embodiment, the light distribution module 5, which has a light source array 1, a lens 2, and a substrate 5a, can be placed on the same substrate as the optical position detection element 4, and these can be integrated. As a result, the relative positions of the light distribution module 5 and the optical position detection element 4 do not change, and therefore, adjustment of their positions becomes unnecessary.

[0080] Furthermore, the effects other than those described in the first embodiment are the same.

[0081] [Third Embodiment] Next, the pupil position detection device of the third embodiment will be described with reference to Figures 8 and 9. Note that in the first and second embodiments, descriptions of components identical to those already described may be omitted.

[0082] In the first and second embodiments, examples were shown in which a lens 2 and a planar mirror 3 are used as the light deflection means, but this embodiment shows an example in which light deflection is performed by a method other than the above.

[0083] Figure 8(a) shows an example of a light deflection means having a microlens array 2a and a reflective mirror 2b. The light distribution module 6 includes a light source array 1, a microlens array 2a, a reflective mirror 2b, and a substrate 6a.

[0084] As shown in (a), the light-emitting parts of the light source array 1 and the lenses of the microlens array 2a are arranged in a one-to-one ratio. Furthermore, the light-emitting parts of the microlens array 2a are offset in the X-axis and Y-axis directions with respect to the optical axis of the lenses, and the amount of offset differs for each light-emitting part. This amount of offset adjusts the deflection angle of the light from the light-emitting parts.

[0085] By placing the substrate on which the microlens array 2a is formed in contact with the substrate of the light source array 1, the light distribution module 6 can be miniaturized and made thinner. In addition, the deflection angle of the light from the light-emitting part can be adjusted easily and with high precision. In other words, the angle of incidence of light to the eyeball 30 can be adjusted easily and with high precision. Furthermore, the light distribution module 6 has a reflective mirror 2b, which enables the reflection of light, thereby simplifying the mounting of optical components such as the microlens array 2a.

[0086] On the other hand, Figure 8(b) shows an example of a light deflection means having a concave curved mirror 2c. The light distribution module 7 includes a light source array 1, a concave curved mirror 2c, and a substrate 7a. By having a concave curved mirror 2c, the number of optical components can be reduced, and the reflection of light is made possible, simplifying the mounting of optical components.

[0087] In addition to the above, diffraction gratings, prisms, and holographic elements can be used as optical deflection methods. However, diffraction gratings and prisms are basically one-dimensional deflection elements. Therefore, when using diffraction gratings or prisms as optical deflection methods, it is necessary to use two or more diffraction gratings or prisms with intersecting deflection directions in combination, or to provide a region division structure on the deflection surface of the diffraction grating or prism to deflect light in two or more intersecting directions.

[0088] Figure 9 shows an example of a configuration in which the light distribution module 6 shown in Figure 8(a) is installed on a spectacle-type support 20. In Figure 9, the light position detection element 4 is placed on the spectacle frame 21, but there are no restrictions on the position where the light position detection element 4 is placed; it should be placed so that reflected light from the eyeball 30 is incident on the light-receiving surface of the light position detection element 4.

[0089] According to this embodiment, the light deflection means is one or more combinations of a convex lens, a planar mirror, a microlens array, a concave curved mirror, a hologram diffraction element, a prism array, or a diffraction grating. This changes the angle of incidence to the eyeball 30 and expands the detection range of the pupil 31 position. Because light deflection is performed with a simple configuration that does not have movable parts, the eyeball tilt position detection device can be miniaturized and the assembly load can be reduced.

[0090] According to this embodiment, the light source array 1 and the optical deflection means such as a microlens array are integrated by arranging them on the same substrate. This makes it possible to miniaturize the eyeball tilt position detection device and reduce the assembly load. Alternatively, the above effects can be obtained by integrating the substrate on which the light source array 1 is arranged and the substrate on which the optical deflection means such as a microlens array 2a is arranged by bringing them into contact.

[0091] Furthermore, other effects are the same as those described in the first and second embodiments.

[0092] [Fourth Embodiment] Next, the display device of the fourth embodiment will be described with reference to Figure 10. Note that in the first to third embodiments, descriptions of components that are the same as those described in the embodiments already described may be omitted.

[0093] Figure 10 shows an example of the configuration of the display device 50 in this embodiment.

[0094] The display device 50 includes an RGB (Red, Green, Blue) laser light source 51, a scanning mirror 52, a planar mirror 53, a half mirror 54, an image generation means 55, and a pupil position detection device 10b.

[0095] The RGB laser light source 51 outputs laser light of three RGB colors, modulated in time. The scanning mirror 52 scans the light from the RGB laser light source 51 in two dimensions. The scanning mirror 52 is, for example, a MEMS mirror. Any mirror with a reflective surface that scans light, such as a polygon mirror or a galvanometer mirror, will suffice. MEMS mirrors are advantageous in terms of miniaturization and weight reduction. The driving method of the MEMS mirror can be electrostatic, piezoelectric, electromagnetic, or any other.

[0096] The planar mirror 53 reflects the scanning light from the scanning mirror 52 toward the half mirror 54. The half mirror 54 transmits a portion of the incident light and reflects the other portion toward the eyeball 30. The half mirror 54 has a concave curved shape, which focuses the reflected light near the pupil 31 of the eyeball 30, forming an image at the position of the retina 32. This projects the image formed by the scanning light onto the retina 32. The light 51a shown by the dashed line in the figure represents the light that forms the image on the retina 32. Note that the amount of reflected light and transmitted light in the half mirror 54 does not necessarily have to be in a 1:1 ratio.

[0097] The pupil position detection device 10b detects the position of the pupil 31 in accordance with eye movement and transmits a feedback signal of the pupil 31 position to the image generation means 55.

[0098] The image generation means 55 has a function to control the deflection angle of the scanning mirror 52 and a function to control the emission of the RGB laser light source 51. The image generation means 55 also receives a feedback signal of the position of the pupil 31 from the pupil position detection device 10b. In accordance with the position of the pupil 31 detected by the pupil position detection device 10b, the deflection angle of the scanning mirror 52 and the emission of the RGB laser light source 51 are controlled to rewrite the projection angle of the image or the image content. This makes it possible to form an image on the retina 32 that follows the change in the position of the pupil 31 due to eye movement (eye tracking).

[0099] The above shows an example in which the display device 50 is a wearable terminal, specifically a head-mounted display (HMD). The display device 50 as a head-mounted display may be attached not only directly to the head of a person, but also indirectly to the head of a person via components such as fixing parts. Furthermore, it may be a binocular display device with a pair of display devices 50 for the left and right eyes.

[0100] Here, we compare the device described in Patent Document 1 with the pupil position detection devices 10, 10a, and 10b of this embodiment. Figure 11 shows the configuration of the eye tracking device described in Patent Document 1.

[0101] In the apparatus described in Patent Document 1, a laser light source is used, and the laser light is scanned by a MEMS mirror to change the angle of incidence of light to the eyeball 30. In contrast, in this embodiment, a light source array 1 having multiple light-emitting units is used as the light source, and the angle of incidence of light to the eyeball 30 is changed by changing the light-emitting units of the light source array 1. Furthermore, in this embodiment, the range of change in the angle of incidence is expanded by using light deflection means (lenses, plane mirrors, microlens arrays, concave curved mirrors, hologram diffraction elements, prism arrays, diffraction gratings, etc.) in conjunction with the light source array 1. In this embodiment, the angle of incidence of light to the eyeball 30 is changed without using movable parts. Therefore, it is more resistant to vibrations and external shocks compared to a configuration with movable parts.

[0102] In the apparatus described in Patent Document 1, the intensity of reflected light irradiated onto the cornea is detected by a photodetector. In contrast, in this embodiment, a two-dimensional PSD or similar optical position detection element 4 is used to detect the position of light reflected by the eyeball 30 and incident on the light-receiving surface of the optical position detection element 4. Since the PSD detects the position of incident light independently of light intensity, even if there is a difference in the amount of reflected light due to the reflection position of the light on the eyeball 30, highly sensitive position detection is possible without being affected by the difference in the amount of reflected light. As a result, the tilt position of the eyeball, such as the pupil, can be detected with high accuracy.

[0103] In this embodiment, a light emission control unit 110 is provided, which adjusts the position of the light-emitting units of the light source array 1 and the timing of light emission between the light-emitting units to light up individually. This allows for the capture of coarse movements of the eyeball 30 so that the reflected light from the eyeball 30 falls onto the light-receiving surface of the optical position detection element 4, and also allows for the capture of fine movements of the eyeball 30 by position detection by the optical position detection element 4.

[0104] In the apparatus described in Patent Document 1, the position of the eyeball is estimated from two peak intensities on the time axis of reflected light from the eyeball (two reflection positions on the cornea). In this embodiment, the position of the eyeball is estimated from the reflection position of one point on the eyeball, such as the cornea. Therefore, the light source array 1 and the optical position detection element 4 do not necessarily have to be in symmetrical positions. In this embodiment, the optical position detection element 4 may not be placed near the specular reflection angle of the eyeball 30, but on the same side as the light source array 1.

[0105] Although the image forming apparatus and image forming method according to the embodiments have been described above, the present invention is not limited to the above embodiments, and various modifications and improvements are possible within the scope of the present invention.

[0106] For example, it can be used in optometry devices that have the function of detecting the tilt of the eyeball and the position of the pupil (cornea). An optometry device refers to a device that can perform various tests such as visual acuity tests, refractive power tests, intraocular pressure tests, and axial length tests. An optometry device is a device that can perform eye examinations without contact with the eyeball and has a support part that supports the subject's face, an eye examination window, a display part that displays information to keep the direction of the subject's eyeball (direction of gaze) constant during the eye examination, a control part, and a measurement part. In order to improve the measurement accuracy of the measurement part, it is required that the subject stare at a single point without moving their eyeball (gaze), and the subject fixes their face to the support part and stares at the display displayed on the display part through the eye examination window. At this time, the eyeball tilt position detection device of this embodiment can be used when detecting the tilt position of the eyeball. The eyeball tilt position detection device is positioned to the side of the measurement part so as not to interfere with the measurement. The tilt position (line of sight) information of the eyeball obtained by the eyeball tilt position detection device can be fed back to the control unit, enabling measurements to be taken according to the tilt position information of the eyeball. [Explanation of Symbols]

[0107] 1. Light source array 1a, 1b light 2. Lenses (an example of a light deflection method) 2a Microlens array 2b Deflection prism 2c Concave curved mirror 3. Planar mirror (an example of a light deflection means) 4. Optical position detection element 5, 6, 7 Light distribution modules 5a, 6a, 7a board 10, 10a, 10b Pupil position detection device 20 Spectacle-shaped support 21 Eyeglass Frames 22 Eyeglass Lenses 30 Eyeball 31 Pupil 32 Retina 50 Display device 51 RGB laser light source 52 Scanning mirrors 53. Flat mirror 54 Half Mirror 55 Image generation means 100 Processing Unit 101 CPU 102 ROM 103 RAM 104 Input / Output Interfaces 105 System Bus 110 Light emission control unit (an example of light emission control means) 120 Pupil position calculation unit (an example of a position calculation means) 121 Detection signal receiving unit 122 Eye rotation angle estimation unit 123 Pupil center position calculation unit P reflection point [Prior art documents] [Patent Documents]

[0108] [Patent Document 1] US2016 / 0166146 [Non-patent literature]

[0109] [Non-Patent Document 1] IEEE 30th International Conference on Micro Electro Mechanical Systems (MEMS), Las Vegas, 2017, pp.304-307

Claims

1. A device for detecting the tilt position of the eyeball, A light source array comprising multiple light-emitting units that emit directional light, The system includes an optical position detection element that detects the optical position of the reflected light from the eyeball. An eyeball tilt position detection device characterized by the following:

2. The light source array includes a surface-emitting laser in which the light-emitting units are arranged in a plane. The eyeball tilt position detection device according to feature 1.

3. In the aforementioned plurality of light-emitting units, the light-emitting timing between the light-emitting units changes at predetermined timings. The eyeball tilt position detection device according to claim 1 or 2.

4. The optical position detection element has a two-dimensional PSD (Position Sensitive Detector). An eyeball tilt position detection device according to any one of claims 1 to 3.

5. The optical position detection element has a plurality of one-dimensional PSDs arranged in a predetermined direction. An eyeball tilt position detection device according to any one of claims 1 to 3.

6. The system includes a light deflection means that causes the aforementioned light to be incident on the eyeball at a predetermined angle, The optical deflection means is one or more of the following: a portion of a convex lens, a mirror, a microlens array, a concave curved mirror, a holographic diffractometer, a prism array, or a diffraction grating. An eyeball tilt position detection device according to any one of claims 1 to 5.

7. The light source array and the light deflection means are arranged on the same substrate. The eyeball tilt position detection device according to feature 6.

8. The light source array is arranged on a first substrate, and the light deflection means is arranged on a second substrate. The first substrate and the second substrate are arranged in contact with each other. The eyeball tilt position detection device according to feature 6.

9. The system includes a light deflection means that causes the aforementioned light to be incident on the eyeball at a predetermined angle, The light source array and the light deflection means are arranged on the same substrate. An eyeball tilt position detection device according to any one of claims 1 to 5.

10. The light position detection element is positioned on the same side as the light source array with respect to the eyeball. An eyeball tilt position detection device according to any one of claims 1 to 9.

11. The system includes processing means for performing the process of detecting the tilt position of the eyeball, The processing means is Light emission control means for controlling the emission of light from the aforementioned light source array, The system includes a position calculation means that calculates the tilt position of the eyeball based on the output of the optical position detection element, The light emission control means controls the light-emitting unit that emits light and the timing of the light emission. An eyeball tilt position detection device according to any one of claims 1 to 10.

12. A display device having an eyeball tilt position detection device according to any one of claims 1 to 11.

13. An optometry device having an eyeball tilt position detection device according to any one of claims 1 to 11.

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