Eyeball tilt position detection device

Abstract

To provide an eyeball inclination position detection device that is resistant to vibration and external impact.SOLUTION: An eyeball inclination position detection device includes: a light source array including a plurality of light-emission parts for emitting light having directivity; and a light position detection element for detecting a light position of reflected light from the eyeball of the light.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an eyeball tilt position detection device. Place Regarding. [Background technology]

[0005] corner In order to detect the position of the membrane and provide feedback to the image drawing position, etc., an eye tracking technology has been disclosed that includes a MEMS (Micro Electro Mechanical Systems) mirror that scans a laser on the eyeball, a photodetector that detects the intensity of the reflected light, and an electronic circuit that estimates the position of the cornea on the eyeball from the detected intensity (see, for example, Patent Document 1 and Non-Patent Document 1). Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technologies of Patent Document 1 and Non-Patent Document 1 have movable structures such as MEMS mirrors, and therefore, the accuracy of detecting the tilt position of the eyeball, such as the corneal position, can sometimes be reduced due to vibrations, external impacts, etc.

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

[0008] A technology according to one aspect of the disclosed technology is an eyeball tilt position detection device mounted on an eyeglass-type support or a head-mounted wearable device, the device having a plurality of light-emitting units that emit light, a light deflection unit that deflects the light emitted by the light-emitting units and reflected by the eyeball and that does not move when detecting the eyeball tilt position, and a light-receiving unit that receives the light deflected by the light deflection unit. ,before The optical path along which the plurality of light beams travel from the eyeball to the light receiving unit is characterized in that no optical deflection unit other than the optical deflection unit, which moves when detecting the tilt position of the eyeball, is disposed. [Effects of the Invention]

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

[0010] [Figure 1] 1 is a diagram illustrating an example of the configuration of a pupil position detection device according to a first embodiment. [Figure 2] 3A to 3C are diagrams illustrating an example of the operation of pupil position detection by the pupil position detection device of the first embodiment. [Figure 3] FIG. 2 is a functional block diagram illustrating an example of a hardware configuration of a processing unit according to the first embodiment. [Figure 4] FIG. 2 is a functional block diagram illustrating an example of components included in a processing unit of the first embodiment. [Figure 5] 6 is a flowchart showing an example of processing by a pupil position calculation unit of the first embodiment. [Figure 6] 5A to 5C are diagrams illustrating a numerical simulation carried out to verify the principle of pupil position detection in the pupil position detection device of the first embodiment. [Figure 7] FIG. 10 is a diagram illustrating an example of the configuration of a pupil position detection device according to a second embodiment. [Figure 8] FIG. 10 is a diagram illustrating an example of an optical deflection means according to the third embodiment. [Figure 9] FIG. 10 is a diagram showing an example of a configuration in which a light distribution module according to a third embodiment is arranged on a glasses-type support body. [Figure 10] FIG. 10 is a diagram illustrating an example of the configuration of a display device according to a fourth embodiment. [Figure 11] FIG. 1 is a diagram showing the configuration of an eye-tracking device described in Patent Document 1. DETAILED DESCRIPTION OF THE INVENTION

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations may be omitted.

[0012] In the embodiments, the "eyeball tilt position" refers to the position of the pupil or cornea of ​​the eyeball. In the following, an example will be described in which the "eyeball tilt position" refers to the position of the pupil, and the "eyeball tilt position detection device" refers to the "pupil position detection device." In the following, the "eyeball tilt position detection device" will be simply referred to as the "pupil position detection device." In addition, an example will be described in which the "pupil position detection device" is mounted on a glasses-type support.

[0013] In the embodiment, the pupil position detection device for the right eye of a person will be described as an example, but the same applies to the left eye. Also, two pupil position detection devices can be provided and applied to both eyeballs.

[0014] [First embodiment] 1 is a diagram showing an example of the configuration of a pupil position detection device according to this embodiment, in which arrows indicate the X, Y, and Z directions.

[0015] 1, pupil position detection device 10 has a light source array 1, a lens 2, a plane mirror 3, a light position detection element 4, and a processing unit 100. Light source array 1 and lens 2 are provided on a spectacle frame 21 of a spectacle-type support body 20, and the plane mirror 3 and light position detection element 4 are provided on a spectacle lens 22 of the spectacle-type support body 20. Processing unit 100 has 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 sections arranged two-dimensionally within a plane. Note that "a plurality of light emitting sections" is synonymous with "a plurality of light emitting points" or "a plurality of light emitting elements."

[0017] Each light-emitting unit emits directional laser light upward in the drawing. The light source array 1 is, for example, a VCSEL (Vertical Cavity Surface Emitting Laser) with the emission direction facing upward in the drawing. However, the light source array 1 is not limited to this, and for example, the light source array 1 may be configured by arranging a plurality of LDs (Laser Diodes) that emit directional laser light two-dimensionally in a plane.

[0018] The wavelength of the light emitted from the light source array 1 is preferably a wavelength of near-infrared light, which is invisible light, so as not to obstruct the visibility of the "person" whose pupil position is to be detected, but is not limited to this and may be visible light.

[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 refracts the light that passes through it, thereby deflecting the light in a predetermined direction. The light source array 1 and the lens 2 are fixed to the same substrate 5a and integrated together to form a light distribution module 5. The light distribution module 5 is fixed to a stable, stationary support, such as an eyeglass frame 21 provided on the eyeglass-type support body 20.

[0020] The light deflected by the lens 2 is reflected by the plane mirror 3 toward the eyeball 30. The plane mirror 3 is fixed to the eyeglass lens 22 of the eyeglass-type support body 20. Due to deflection by the lens 2 and reflection by the plane mirror 3, the light from the light source array 1 is incident at a predetermined angle on the center of the pupil 31 of the eyeball 30 when the eye is looking straight ahead. The lens 2 and the plane mirror 3 have the function of deflecting the light from the light source array 1 and making it incident on the eyeball 30. The lens 2 and the plane mirror 3 are an example of "light deflection means for making light incident on the eyeball at a predetermined angle."

[0021] The optical deflection means is not limited to the lens 2 and the plane mirror 3. Any component or combination of components may be used as long as it is possible to direct light from the light source array 1 to the eyeball at a predetermined angle. However, in addition to the above-mentioned convex lens, the optical deflection means may be any one or a combination of two or more of a microlens array, a concave curved mirror, a hologram diffraction element, a prism array, or a diffraction grating, which can provide effects such as an expanded pupil detection range, a more compact device, and a reduced assembly load for the pupil position detection device 10. Other examples of such optical deflection means will be described in detail in the third embodiment.

[0022] The pupil surface (corneal surface) is a transparent body that contains water and generally has a reflectance of approximately 2 to 4%. Light that enters the vicinity of the pupil 31 is reflected at a reflection point P on the pupil surface (corneal surface) of the eyeball 30, and the reflected light enters a position sensitive detector 4. The position sensitive detector 4 is, for example, a two-dimensional PSD (Position Sensitive Detector).

[0023] The PSD detects the direction of the normal vector of the reflection point, i.e., the three-dimensional shape. The position of the pupil center is "estimated" by matching the detected three-dimensional shape with the eyeball model.

[0024] The two-dimensional PSD detects current values ​​corresponding to the distance to the electrodes in two orthogonal directions on the light-receiving surface from the position of incident light on the light-receiving surface, and 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 incident light independently of the 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, it is possible to perform highly sensitive position detection without being affected by the difference in the amount of reflected light. Furthermore, compared to using an imaging element such as a CCD (Charge Coupled Device) or CMOS (Complementary Metal-Oxide-Semiconductor) as the light position-sensitive detector 4, there is an advantage in that position detection does not require complex image processing, thereby reducing the processing load.

[0025] However, the light position sensitive detector 4 is not limited to a two-dimensional PSD. The position of 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, one-dimensional PSDs are less expensive than two-dimensional PSDs, etc., and therefore, the cost of the pupil position detection device 10 can be reduced.

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

[0027] The position of light incident on the light receiving surface of the position-sensitive detector 4 is an example of the "light position of light reflected from the eyeball."

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

[0029] Pupil position calculation unit 120 is electrically connected to light position detection element 4 and receives a detection signal output by light position detection element 4 in accordance with the position of light incident on the light receiving surface of light position detection element 4. Pupil position calculation unit 120 calculates the position of pupil 31 based on the detection signal. Pupil position calculation unit 120 is an example of a "position calculation means."

[0030] When the direction of light reflected from the eyeball 30 changes due to eyeball movement, such as the rotation of the eyeball 30, the reflected light may miss the light-receiving surface of the position-sensitive detector 4. To prevent this, the light-emission control unit 110 sequentially or selectively changes the light-emitting units that emit light in the light source array 1. When the light-emitting units are changed, the position of the light emitted changes within the plane on which the light-emitting units are arranged in the light source array 1, and the angle of incidence of light that enters the eyeball 30 via the lens 2 and the plane mirror 3 changes. The change in the angle of incidence on the eyeball 30 changes the position of the light that is reflected from the eyeball 30 and enters the light-receiving surface of the position-sensitive detector 4. Therefore, by changing the light-emitting units that emit light in the light source array 1 in accordance with the eyeball movement of the eyeball 30, it is possible to prevent the light reflected from the eyeball 30 from missing the light-receiving surface of the position-sensitive detector 4.

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

[0032] 2 is a diagram illustrating an example of the operation of pupil position detection by the pupil position detection device 10. Fig. 2 shows the behavior of light emitted from two light-emitting units located at different positions in the light source array 1. Light 1a from one light-emitting unit is represented by a dotted line, and light 1b from the other light-emitting unit is represented by a dashed-dotted line. Also, (a) shows the eyeball 30 when looking directly ahead, that is, when the eyeball 30 is facing forward, and (b) shows the eyeball 30 when it is rotating.

[0033] In (a), light 1a, indicated by a dotted line, is reflected by the eyeball 30 and enters near the center of the light-receiving surface of the position-sensitive detector 4. Therefore, the position-sensitive detector 4 can detect changes 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 position-sensitive detector 4. On the other hand, light 1b, indicated by a dash-dot line, is reflected by the eyeball 30 but does not enter the light-receiving surface of the position-sensitive detector 4. Therefore, light 1b does not contribute to the detection signal of the position-sensitive detector 4. As a result, 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 compared to (a), the light 1a that was incident on the light-receiving surface of the position-sensitive detector 4 during normal vision moves away from the light-receiving surface of the position-sensitive detector 4 and no longer contributes to the detection signal of the position-sensitive detector 4. This prevents the pupil position calculation unit 120 from calculating the position of the pupil 31. Conversely, the light 1b is incident near the center of the light-receiving surface of the position-sensitive detector 4. This allows the position-sensitive detector 4 to detect changes in the incident position of the light 1b on the light-receiving surface in response to 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 position-sensitive detector 4.

[0035] Thus, while light from one light-emitting unit can only detect the eye movement of the eyeball 30 within a limited angular range, in this embodiment, the light-emitting units of the light source array 1 are changed to change the angle of incidence onto the eyeball 30, thereby expanding the detection range for the eye movement of the eyeball 30. This makes it possible to expand the detection range for the position of the pupil 31.

[0036] The light-emitting units of the light source array 1 are changed in a time series manner in response to the eyeball movement of the eyeball 30 by a control signal from the light-emitting control unit 110. By controlling the light-emitting units in response to (following) the eyeball movement of the eyeball 30, it is possible to improve the light utilization efficiency and shorten the estimation time. However, it is not necessarily required to "respond to eyeball movement." For example, the light-emitting unit positions can be raster-scanned at regular time intervals independently of the eyeball movement to obtain the coarse movement position of the eyeball.

[0037] 2 illustrates light emitted from only two light-emitting elements for the sake of simplicity, but in this embodiment, more light-emitting elements provided in the light source array 1 can be used in accordance with the eye movement of the eyeball 30. In this case, the number and positions of the light-emitting elements in the light source array 1 are optimized in accordance with the size of the light-receiving surface of the light position detection element 4 and the size of the eyeball so that the position of the pupil 31 is detected appropriately.

[0038] FIG. 3 is a functional block diagram showing an example of the hardware configuration of the processing unit 100 of this embodiment.

[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 I / F (Interface) 104. These are interconnected via a system bus 105.

[0040] The CPU 101 performs overall control of the operation of the processing unit 100. The CPU 101 also executes a process of calculating the position of the pupil 31 based on the detection signal of the light position detection element 4.

[0041] The CPU 101 executes the above-mentioned control and processing and realizes various functions described below by executing programs stored in the ROM 102 or the like using the RAM 103 as a work area. Note that some or all of the functions of the CPU 101 may be realized by hardware using wired logic such as an ASIC (application specific integrated circuit) or an FPGA (field-programmable gate array).

[0042] The input / output I / F 104 is an interface for connecting to external devices such as a PC (Personal Computer) and video equipment.

[0043] FIG. 4 is a diagram showing an example of components of the processing unit 100 of this embodiment in the form of functional blocks. Note that each functional block shown in FIG. 4 is conceptual and does not necessarily have to be physically configured as shown. All or part of each functional block can be configured by functionally or physically distributing or connecting them in any unit. All or any part of each processing function performed by each functional block can be realized by a program executed by the above-mentioned CPU 101, or can be realized as hardware using wired logic.

[0044] As described above, the processing unit 100 has the light emission control unit 110 and the pupil position calculation unit 120. The function of the light emission control unit 110 is as described above. The pupil position calculation unit 120 has 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 light position detecting element 4 and outputs it to the eyeball rotation angle estimating 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 light 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] FIG. 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 a 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 a 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 function or a quadratic function. However, this is not limited to this. The formula can take any form as long as it determines the rotation angle from the designed light incident angle and the landing position of the reflected light on the optical position detection element. As a simple approximation, a quadratic function calculation 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. A simplified model eye and the like have long been known as a general model of the eyeball surface shape (see, for example, "Optical Mechanism of the Eye," Seimitsu Kikai 27-11, 1961).

[0052] The plane 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 plane mirror 3 is incident on the eyeball 30. The incident light on the eyeball 30 is reflected by the eyeball 30 rotated by a predetermined angle and propagates towards the position-sensitive detector 4. The angle of the light incident on the eyeball 30 is calculated and designed in advance using ray tracing calculations or the like so that this propagating light is incident on the center position of the light-receiving surface of the position-sensitive detector 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 plane to the surface of the eyeball 30. From the solution of such theoretical analysis, an inverse calculation formula (approximation formula) for estimating the rotation angle of the eyeball 30 by polynomial approximation is determined.

[0054] The above is the preparation performed for calculating the pupil position prior to step S61 in Fig. 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 a memory such as the ROM 102 of the processing unit 100, and are referred to and used in the light emission control by the light emission control unit 110 and in the pupil position calculation by the pupil position calculation unit 120.

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

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

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

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

[0059] FIG. 6 is a diagram illustrating a numerical simulation carried out 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 the plane mirror 3 and the optical position sensitive detector 4 are placed in a plane 10 mm away from the eyeball 30 in the -Z-axis direction in Fig. 1. The reference angles (θx, θy) of the eyeball 30 are determined by changing the rotation angle of the eyeball 30 at five points in the X direction and three points in the Y direction, both in 5° increments.

[0061] The horizontal axis of Figure 6 represents the amount of change in the eyeball rotation angle in the X direction, and the vertical axis represents the amount of change in the eyeball rotation angle in the Y direction. The rotation angle was changed at five points in the X direction and three points in the Y direction, both in 5° increments, and the incident angle at each point was used as the reference (angle change (0, 0)).

[0062] In the numerical simulation, the exit angle (reflection angle at the plane mirror 3) of light reflected by the eyeball 30 and incident on the center of the position sensitive detector 4 at the position of the plane mirror 3 was calculated by numerical calculation for each reference angle of the eyeball 30. The center of the position sensitive detector 4 is expressed as coordinates (0, 0).

[0063] In addition, 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 the 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 positions. When the rotation angle of the eyeball 30 is small, good agreement is obtained. In this case, the error is limited to a maximum of approximately 0.1° within the range of |Δθx| ≦ 2.5°. Here, the value 2.5° is half the reference angle in 5° increments, representing the condition under which no areas of light are detected. Furthermore, because the planar mirror 3 and the optical position-sensitive detector 4 are assumed to be arranged in the X direction within a plane, the error in the Y direction is smaller than that in the X direction.

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

[0066] The above numerical simulation results indicate estimated values ​​for the angle of rotation of the eyeball 30. The angle of rotation of the eyeball 30 can be defined as the angle formed by a line connecting the center of the eyeball 30, i.e., the center position of rotation, and the center position of the cornea, with 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 position of the eyeball 30 in the direction of the angle of rotation of the eyeball 30 by the distance between the center positions of the eyeball 30 and the cornea. The distance from the center position of the eyeball 30 to the center position of the cornea is given in advance by an eyeball model.

[0067] In this way, it has been verified by numerical simulation that the calculation process of the pupil position calculation unit 120 shown in FIG. 5 can calculate the position of the pupil 31 with sufficient accuracy.

[0068] As described above, this embodiment includes a light source array 1 including a plurality of light-emitting units that emit directional light, and a detection element that detects the position of light reflected by the eyeball from the light-emitting units. By changing the light-emitting units of the light source array 1 at a predetermined timing, the angle of incidence on the eyeball 30 is changed, thereby expanding the detection range for the position of the pupil 31. In this embodiment, this pupil position detection is performed using a non-mechanical configuration without using a movable structure such as a MEMS mirror. This makes it possible to achieve pupil position detection that is resistant to vibrations and external impacts. In other words, this embodiment provides a device for detecting the tilt position of the eyeball, such as the pupil position, that is resistant to vibrations and external impacts.

[0069] According to this embodiment, since there is no moving part such as a MEMS mirror, it is possible to prevent the amount of light reflected by the eyeball from not reaching the photodetector, thereby improving light utilization efficiency. It is also possible to suppress the influence of noise such as ambient light. Furthermore, since there is no dynamic deformation like a MEMS mirror, it is possible to ensure the accuracy of pupil position detection without complicated adjustments.

[0070] According to this embodiment, a two-dimensional or one-dimensional PSD is used as the position-sensitive detector 4 to detect the incident position of reflected light from light irradiated onto the eyeball on the light-receiving surface of the position-sensitive detector 4. Because the position of the incident light is detected independently of the intensity of the incident light, even if there is a difference in the amount of reflected light due to the position of light reflection 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 no imaging element such as a CCD is used to detect the position of incident light, the processing load of image processing, etc. can be reduced. Furthermore, high-speed and real-time detection of the position of the pupil, etc. can be ensured without using expensive components such as a high-speed calculator or large-capacity memory. When a one-dimensional PSD is used as the light position-sensitive detector 4, a device for detecting the tilt position of the eyeball, such as the 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 being arranged on the same substrate. This makes it possible to reduce the size of the eyeball tilt position detection device and the assembly load. Note that the first substrate on which the light source array 1 is arranged and the second substrate on which the lens 2 is arranged may be brought into contact with each other to integrate the two, thereby achieving the above-mentioned effect.

[0073] According to this embodiment, a VCSEL is used for the light source array 1, and therefore the angle of incidence on the eyeball 30 can be changed by changing the light emitting portion of the VCSEL, thereby expanding the detection range for the position of the pupil 31.

[0074] Although the above example shows a configuration including one light source array 1, a configuration including multiple light source arrays may be used. This further expands the range in which the angle of incidence onto the eyeball 30 can be changed, and further expands the detection range for the position of the pupil 31.

[0075] [Second embodiment] Next, a pupil position detecting device according to a second embodiment will be described with reference to Fig. 7. In the second embodiment, the description of the same components as those in the embodiments already described may be omitted.

[0076] FIG. 7 is a diagram showing an example of the configuration of a pupil position detecting device 10b of this embodiment.

[0077] In the pupil position detection device 10b, a light position detection element 4 is arranged in the direction of retroreflection of light that is incident on the eyeball 30 via the light source array 1 and the lens 2. In other words, the light position detection element 4 is arranged on the same side of the eyeball 30 as the light source array 1.

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

[0079] According to this embodiment, the light distribution module 5 having the light source array 1, the lens 2, and the substrate 5a can be arranged on the same substrate as the position sensitive detector 4, and these can be integrated. This prevents the relative positions of the light distribution module 5 and the position sensitive detector 4 from changing, eliminating the need to adjust their positions.

[0080] Other effects are the same as those described in the first embodiment.

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

[0082] In the first and second embodiments, examples have been shown in which the lens 2 and the plane mirror 3 are used as the light deflection means, but in this embodiment, an example in which light deflection is performed by a method other than these will be shown.

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

[0084] As shown in (a), the light-emitting units of the light source array 1 and the lenses of the microlens array 2a are arranged in a one-to-one correspondence. The light-emitting units are also arranged offset in the X-axis and Y-axis directions with respect to the optical axes of the lenses of the microlens array 2a, with the amount of offset varying for each light-emitting unit. The deflection angle of the light from the light-emitting units is adjusted by this amount of offset.

[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 made smaller and thinner. In addition, the deflection angle of light from the light-emitting unit can be adjusted easily and with high precision. In other words, the angle of incidence of light on the eyeball 30 can be adjusted easily and with high precision. Furthermore, the light distribution module 6 has a reflective mirror 2b, which enables light to be reflected, simplifying the implementation of optical components such as the microlens array 2a.

[0086] 8(b) shows an example of a light deflection means having a concave curved mirror 2c. The light distribution module 7 has a light source array 1, a concave curved mirror 2c, and a substrate 7a. The use of the concave curved mirror 2c reduces the number of optical components and enables light to be folded back, simplifying the implementation of the optical components.

[0087] In addition to the above, diffraction gratings, prisms, hologram elements, etc. can also be used as light deflection means. Note that diffraction gratings and prisms are basically one-dimensional deflection elements. Therefore, when using a diffraction grating or prism as light deflection means, it is necessary to combine two or more diffraction gratings or prisms whose deflection directions intersect, or to provide an area division structure on the deflection surface of the diffraction grating or prism to deflect light in two or more intersecting directions.

[0088] 9 shows an example of a configuration in which the light distribution module 6 shown in Fig. 8(a) is provided on a spectacle-type support body 20. In Fig. 9, the position sensitive detector 4 is disposed on the spectacle frame 21, but there are no restrictions on the position at which the position sensitive detector 4 is disposed, as long as it is disposed so that reflected light from the eyeball 30 is incident on the light receiving surface of the position sensitive detector 4.

[0089] According to this embodiment, the light deflection means is any one or a combination of two or more of the following: a partial region of a convex lens, a plane 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 onto the eyeball 30, making it possible to expand the detection range for the position of the pupil 31. Because light deflection is performed with a simple configuration that does not have any moving parts, the eyeball tilt position detection device can be made smaller 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 arranged on the same substrate, thereby integrating the two. This makes it possible to reduce the size of the eyeball tilt position detection device and the assembly load. Note that the substrate on which the light source array 1 is arranged and the substrate on which the optical deflection means such as the microlens array 2a is arranged may be brought into contact with each other to integrate the two, thereby achieving the above-mentioned effect.

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

[0092] [Fourth embodiment] Next, a display device according to a fourth embodiment will be described with reference to Fig. 10. In the first to third embodiments, the description of the same components as those in the embodiments already described may be omitted.

[0093] FIG. 10 is a diagram showing an example of the configuration of a display device 50 of this embodiment.

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

[0095] The RGB laser light source 51 modulates and outputs laser light of three RGB colors over time. The scanning mirror 52 scans the light from the RGB laser light source 51 two-dimensionally. The scanning mirror 52 is, for example, a MEMS mirror. Any mirror having a reflective portion for scanning light, such as a polygon mirror or a galvanometer mirror, will do. MEMS mirrors are advantageous in terms of size and weight reduction. The driving method for the MEMS mirror may be electrostatic, piezoelectric, electromagnetic, or other.

[0096] The plane 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 a portion of it toward the eyeball 30. The half mirror 54 has a concave curved surface, and converges the reflected light near the pupil 31 of the eyeball 30, forming an image at the position of the retina 32. In this way, the image formed by the scanning light is projected onto the retina 32. Light 51a indicated by a dashed line in the figure represents light that forms an image on the retina 32. It should be noted that the light amounts of the reflected light and transmitted light from the half mirror 54 do not necessarily have to be one-to-one.

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

[0098] The image generating means 55 has a function of controlling the deflection angle of the scanning mirror 52 and a function of controlling the light emission of the RGB laser light source 51. The image generating means 55 also receives a feedback signal of the position of the pupil 31 from the pupil position detecting device 10b. According to the position of the pupil 31 detected by the pupil position detecting device 10b, the image generating means 55 controls the deflection angle of the scanning mirror 52 and the light emission of the RGB laser light source 51, and rewrites the projection angle of the image or the image content. This makes it possible to form an image on the retina 32 that tracks (eye-tracks) the change in the position of the pupil 31 accompanying eye movement.

[0099] The above shows an example in which the display device 50 is a head mounted display (HMD) that is a wearable terminal. The display device 50 as a head mounted display may be worn directly on the head of a person, or may be worn indirectly on the head of a person via a member such as a fixing part. Also, a binocular display device having a pair of display devices 50 for the left and right eyes may be used.

[0100] Here, the pupil position detection devices 10, 10a, and 10b of this embodiment will be compared with the device described in Patent Document 1. Fig. 11 is a diagram showing the configuration of the eye tracking device described in Patent Document 1.

[0101] The device described in Patent Document 1 uses a laser light source, and scans the laser light with a MEMS mirror to change the angle of incidence of the light on the eyeball 30. In contrast, in this embodiment, a light source array 1 having multiple light-emitting elements is used as the light source, and the angle of incidence of the light on the eyeball 30 is changed by changing the light-emitting elements 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 (lens, flat mirror, microlens array, concave curved mirror, hologram diffraction element, prism array, diffraction grating, etc.) in combination with the light source array 1. In this way, in this embodiment, the angle of incidence of the light on the eyeball 30 is changed without using any movable parts. Therefore, compared to a configuration that uses a movable part, it is more resistant to vibrations, external impacts, etc.

[0102] In the device described in Patent Document 1, a photodetector detects the reflected light intensity of light irradiated onto the cornea, whereas in this embodiment, a two-dimensional position-sensitive detector 4 such as a PSD is used to detect the position of light reflected by the eyeball 30 and incident on the light-receiving surface of the position-sensitive detector 4. Because 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 position of light reflection 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, and the light emission control unit 110 shifts the positions of the light emitting units of the light source array 1 and the light emission timing between the light emitting units to individually light up. This allows coarse movement of the eyeball 30 to be detected, and the reflected light from the eyeball 30 to fall on the light receiving surface of the optical position detection element 4, and fine movement of the eyeball 30 to be detected by position detection by the optical position detection element 4.

[0104] In the device described in Patent Document 1, the eyeball position is estimated from two peak intensities of light reflected from the eyeball on the time axis (two reflection positions on the cornea). In this embodiment, the eyeball position is estimated from the reflection position of one point on the eyeball, such as the cornea. Therefore, the light source array 1 and the position-sensitive detector 4 do not necessarily have to be positioned symmetrically. In this embodiment, the position-sensitive detector 4 may be positioned on the same side as the light source array 1, rather than being positioned near the specular reflection (specular reflection) angle of the eyeball 30.

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

[0106] For example, the present invention can be adopted in an optometry device capable of detecting the tilt of the eyeball and pupil position (cornea). An optometry device is a device capable of performing various tests, such as visual acuity tests, eye refraction tests, intraocular pressure tests, and axial length tests. An optometry device is a device capable of performing non-contact tests on the eyeball. It comprises a support unit for supporting the subject's face, an examination window, a display unit for displaying information to keep the subject's eyeball (gaze direction) constant during the eye examination, a control unit, and a measurement unit. To improve the measurement accuracy of the measurement unit, the subject is required to gaze at a single point without moving the eyeball (gaze direction). The subject fixes their face on the support unit and gazes at an object displayed on the display unit through the examination window. The eyeball tilt position detection device of this embodiment can be used to detect the tilt position of the eyeball. The eyeball tilt position detection device is positioned to the side of the measurement unit so as not to interfere with the measurement. The eyeball tilt position (gaze) information obtained by the eyeball tilt position detection device can be fed back to the control unit, allowing measurements to be made according to the eyeball tilt position information. [Explanation of symbols]

[0107] 1 Light source array 1a, 1b light 2. Lens (an example of a light deflection means) 2a Microlens array 2b Deflecting prism 2c Concave curved mirror 3. Plane mirror (an example of an optical deflection means) 4 Optical position sensitive detector 5, 6, 7 Light distribution module 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 mirror 53 Plane Mirror 54 Half Mirror 55 Image generation means 100 Processing section 101 CPU 102 ROM 103 RAM 104 Input / Output Interface 105 System Bus 110 Light emission control unit (an example of a light emission control means) 120 Pupil position calculation unit (an example of a position calculation means) 121 Detection signal receiver 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. An eyeball tilt position detection device mounted on an eyeglass-type support or a head-mounted wearable device, a plurality of light emitting units that emit light; a light deflection unit that deflects light emitted by the light emitting unit and reflected by the eyeball, and that is not movable when detecting the tilt position of the eyeball; a light receiving unit that receives the light deflected by the light deflection unit; and An optical deflection unit that moves when detecting the tilt position of the eyeball and is separate from the optical deflection unit is not disposed in the optical path along which the plurality of light beams travel from the eyeball to the light receiving unit. An eyeball tilt position detection device characterized by:

2. The light emitted from the light emitting unit and detected by the light receiving unit is reflected once or twice by the eyeball tilt position detection device.

2. The eyeball tilt position detection device according to claim 1.

3. When the light is reflected twice by the eyeball tilt position detection device, the reflection occurs at the light deflection unit.

3. The eyeball tilt position detection device according to claim 2.

4. At least one of the light deflection units is provided on a plane of the eyeglass-type support or the head-mounted wearable device that intersects with the normal viewing direction of the eyeball.

2. The eyeball tilt position detection device according to claim 1.

5. A plane of the eyeglass-type support or the head-mounted wearable device that intersects with the normal viewing direction of the eyeball is a plane perpendicular to the normal viewing direction of the eyeball.

5. The eyeball tilt position detection device according to claim 4.

6. The distance between the position where the light emitted from the light emitting unit is reflected by the optical deflection unit and a plane that is perpendicular to the surface of the eyeglass-type support or the head-mounted wearable device and includes the light emitting unit is closer than the distance between the position where the light deflected by the optical deflection unit is reflected by the eyeball and a plane that is perpendicular to the surface of the eyeglass-type support or the head-mounted wearable device and includes the light emitting unit.

6. The eyeball tilt position detection device according to claim 5.

7. At least one of the light deflection units is provided on a member different from a member on which the light emitting unit is provided in the eyeglass-type support or the head-mounted wearable device.

7. The eyeball tilt position detection device according to claim 6.

8. The light emitting unit emits light toward a plane of the eyeglass-type support or the head-mounted wearable device that intersects with the normal viewing direction of the eyeball.

8. The eyeball tilt position detection device according to claim 7.

9. At least one of the light deflection units deflects the light emitted from the light emitting unit toward a plane intersecting the normal viewing direction of the eyeball in the eyeglass-type support or the head-mounted wearable device.

9. The eyeball tilt position detection device according to claim 8.

10. The light receiving unit is an image sensor.

10. The eyeball tilt position detection device according to claim 9.

11. The imaging element detects the position of light based on the spatial intensity distribution of light incident on the imaging surface. The eyeball tilt position detection device according to claim 10.

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