Video display device

Abstract

This video display device comprises: an optical unit having a display unit and an optical element; a means for driving the optical element; a position detection means for detecting the position of the drive means by transmitting and receiving infrared light; and a line-of-sight detection means for detecting the line of sight of a user by using infrared light. In a projection drawing orthogonal to the optical axis of the optical unit, when assuming a circle having as its radius a distance from the optical axis to a light-emitting unit of the position detection means and also assuming an angle range facing the outside of the circle on the basis of the directivity angle of the light-emitting unit, the direction of light emission from the light-emitting unit is included in the angle range, or the direction of light emission is not included in the angle range, and the angle formed by the line-of-sight detection direction of the line-of-sight detection means and the position detection direction of the position detection means is larger than the directivity angle.

Description

Video display device

[0001] The present invention relates to a technique for adjusting a focal length in a video display device, and in particular to the use of the technique in combination with a line-of-sight detection function.

[0002] There are image display devices that users wear on their heads. These devices can display 3D images using binocular parallax between the left and right eyes. Examples of such devices include virtual reality (VR) devices, augmented reality (AR) devices, and mixed reality (MR) devices.

[0003] These image display devices may experience a significant burden on the user due to a vergence accommodation conflict (VAC) caused by a mismatch between the convergence distance and accommodation distance (or focal distance) of the two eyes. To solve this problem, a variable-focus mechanism has been proposed that changes the accommodation distance of the display optical system. A variable-focus mechanism controls and drives an optical element along the optical axis using a driving means such as a motor based on position information from a position detection means. High-precision position detection means include an optical encoder that detects position using infrared light. These image display devices also have a gaze detection means, which enables functions such as menu selection based on the detection results. A common gaze detection means is a configuration that uses a corneal reflex method to detect the gaze using infrared light.

[0004] Japanese Patent Application Laid-Open No. 2003-124222 discloses an imaging device having a line-of-sight detection means that uses infrared light and an eye proximity detection function that detects the approach of a face.

[0005] Japanese Patent Application Laid-Open No. 2021-093624

[0006] The prior art disclosed in the above-mentioned patent document involves switching the timing of light emission from the light source for gaze detection and eye proximity detection. Therefore, gaze detection and eye proximity detection cannot be used simultaneously. Furthermore, in an image display device in which both the position detection means and the gaze detection means use infrared light, if both are used simultaneously, there is a possibility that they may interfere with each other, for example, when infrared light emitted by the position detection means is incident on the gaze detection means.

[0007] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an image display device that can simultaneously use a position detection unit and a line of sight detection unit.

[0008] The image display device according to the present invention is a head-mounted image display device, comprising: an optical unit having a display unit and an optical element; drive means for driving at least one of the display unit and the optical element; position detection means having a first light-emitting unit for emitting first infrared light and a first light-receiving unit for receiving the first infrared light irradiated from the first light-emitting unit, and for detecting a position of the drive means; and line-of-sight detection means having a second light-emitting unit for irradiating second infrared light and a second light-receiving unit for capturing the second infrared light irradiated from the second light-emitting unit and reflected by a user's eye, and for detecting the line of sight of the user, wherein the direction in which the first light-emitting unit of the position detection means is pointed is defined as a position detection direction, and a range of an angle θ (θ<90°) from the position detection direction is defined as a directivity angle, In a projection diagram in which the position detection means and the line of sight detection means are projected onto a plane perpendicular to the optical axis direction of the optical unit, a position where an imaginary circle having a radius equal to the distance from the optical axis to the first light-emitting unit and the first light-emitting unit overlap is defined as the origin of the first infrared light, and a tangent to the imaginary circle at the origin is divided into a first portion and a second portion with the origin as the boundary, a first line segment is drawn from the origin to the opposite side of the imaginary circle so that the angle between the first portion is θ, and a second line segment is drawn from the origin to the opposite side of the imaginary circle so that the angle between the first line segment and the second portion is θ, and an angle between the first line segment and the second line segment is defined as an angle range R, the following (i) or (ii) is satisfied: (i) the position detection direction of the position detection means is included in the angle range R. (ii) The position detection direction of the position detection means is not included in the angle range R, and the angle formed by the position detection direction and the gaze detection direction, which is the direction in which the second light receiving unit of the gaze detection means is pointed, is larger than the directivity angle.

[0009] According to the present invention, it is possible to provide an image display device that can simultaneously use a position detection means and a line of sight detection means.

[0010] FIG. 1 is a detailed block diagram of the optical unit of the video display device; FIG. 2 is a diagram illustrating possible areas for arranging the position detection means and the line of sight detection means; FIG. 3 is a diagram illustrating the first embodiment; FIG. 4 is a diagram illustrating a modified example of the first embodiment; FIG. 5 is a diagram illustrating the second embodiment; FIG. 6 is a diagram illustrating the third embodiment; FIG. 7 is a diagram illustrating the optical axis direction position of the line of sight detection means in the second embodiment; FIG. 8 is a diagram illustrating the external appearance and main body of a head-mounted video display device; FIG. 9 is a diagram illustrating an optical encoder and a line of sight camera; FIG. 10 is a diagram illustrating the directivity of the light source of the optical encoder;

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, and the like of the components described in these embodiments are not intended to limit the scope of the present invention to those dimensions. Furthermore, the materials, shapes, and the like of components described once in the following description will remain the same in subsequent descriptions unless otherwise specified. Well-known or publicly known technologies in the relevant technical field can be applied to configurations and processes not specifically illustrated or described. Furthermore, the present invention is not limited to these embodiments, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the present invention.

[0012] First, a configuration common to each embodiment will be described with reference to the drawings.

[0013] 9 shows a head mounted display as a head-mounted image display device according to the present disclosure, hereinafter referred to as HMD 100. First, eye position adjustment during viewing will be described.

[0014] The HMD 100 can display a good image when the relative positions of the user's eyes and the optical unit 20 are within an appropriate range. Therefore, the user generally adjusts the wearing position beforehand. This adjustment positions the left eye 4a and the right eye 4b near the center of the optical axis of the eyepiece lenses 12a and 12b.

[0015] 9(a) is an external view of the HMD 100, which is composed of a main body 1, a head-mounted mechanism 2, and a connecting mechanism 3 that connects the main body 1 and head-mounted mechanism 2 of the HMD 100. The tightening force of the headband-shaped band of the head-mounted mechanism 2 can be adjusted using an adjustment mechanism (not shown). The connecting mechanism 3 includes a vertical shift mechanism and a tilt mechanism, and can change the angle and relative distance between the main body 1 and the head-mounted mechanism 2.

[0016] 9B is a front view of the main body 1 as seen from the user's viewing side. The main body 1 has a left optical unit 20a that displays an image for the user's left eye 4a and a right optical unit 20b that displays an image for the user's right eye 4b. The drive mechanisms 21a and 21b are rotary motors that independently move the left optical unit 20a and the right optical unit 20b in a first direction (indicated by the arrow Sx in the figure).

[0017] As described above, the vertical direction is adjusted by the band positions of the connecting mechanism 3 and the head mounting mechanism 2 in FIG. 9( a ), and the horizontal direction is adjusted by the drive mechanism 21 .

[0018] [Explanation of the detailed configuration of the entire optical unit] Next, the entire optical system will be described. FIG. 1 is a diagram illustrating the detailed configuration of the optical unit 20 shown in FIG. 9(b). The symbols "a" are added to the reference numerals of components related to the user's left eye 4a, and the symbols "b" are added to the reference numerals of components related to the user's right eye 4b to distinguish them. For example, the optical unit 20 is referred to as the optical unit 20a for the left eye and the optical unit 20b for the right eye. Note that when it is not necessary to distinguish between left and right, or when it is clear which one is being referred to, the symbols "a" or "b" are omitted and the unit is simply referred to as the optical unit 20.

[0019] 1, a display panel 10 as a display unit for displaying a viewing image, a driven lens 11, and an eyepiece 12 are arranged in this order on an optical axis 13 to realize an optical system that achieves a wide viewing angle. The optical elements include at least the driven lens 11. The driven lens 11 and the eyepiece 12 may be a single lens or a lens group consisting of multiple lenses.

[0020] The driven lens 11 is mounted on a frame 14 and driven by a motor 18, which serves as a driving means, along a guide 17 in the direction of the arrow in the figure on the optical axis. Since the distance between the driven lens 11 and the display panel 10 is variable, the focal length of the optical system of the optical unit 20 can be changed by mechanical operation. The motor 18 may be a stepping motor, a voice coil motor, an ultrasonic motor, or the like. The movement of the motor 18 is detected by an optical encoder 15, which serves as a position detection means. The motor is feedback-controlled based on the position information obtained from the optical encoder 15.

[0021] 1, the driven lens 11 is configured to be driven by the motor 18, but a variable focus function can be realized by a configuration in which at least one of the display panel 10 and the driven lens 11 is driven. In other words, the driving means only needs to be able to change the distance between the driven lens 11 and the display panel 10 in the optical axis direction.

[0022] In addition, in FIG. 1, the motor 18 and the optical encoder 15 are drawn side by side in the optical axis direction, but this is a schematic illustration of the two being placed close to each other, and the actual positional relationship is not limited to this.

[0023] The display panel 10 and eyepiece lens 12 in Figure 1 are fixed in place by a lens barrel structure (not shown). The guide 17 of the driven lens 11 is also fixed to the lens barrel structure. The lens barrel of the HMD 100 is often made of a black resin material so that it is not affected by visible light that enters from the outside before the image on the display panel 10 reaches the eye. The lens barrel structure only needs to function as a fixing part, and there is a high degree of freedom in its shape.

[0024] A gaze camera 16, which serves as a gaze detection means, is disposed at the eye-side end of the optical unit 20. The gaze camera 16 is fixed to a lens barrel structure (not shown). As shown in FIG. 10( b), the gaze camera 16 emits near-infrared light (second infrared light) from a light source 161 (second light-emitting unit), such as an infrared LED, fixed to the lens barrel structure. The image of the infrared light reflected by the user's eye is captured by an image sensor 162 (second light-receiving unit), thereby detecting the user's gaze direction. Near-infrared light is typically light with a wavelength of approximately 750 nm to 1000 nm. However, the wavelength of the gaze camera 16 is not necessarily limited to the near-infrared region, as long as it is capable of gaze detection.

[0025] As described above, the user's eye is adjusted in advance to be near the center of the optical axis. Therefore, the eye camera 16 is fixed facing in a direction that clearly captures the eye near the center of the optical axis. Furthermore, to reliably capture a reflected image, the eye camera is fixed as close to the inner diameter as possible at the center of the optical axis.

[0026] [Explanation of Optical Encoder] Fig. 10(a) is a cross-sectional view illustrating the optical encoder 15 used in this embodiment. The head unit 30 includes an LED 32 (first light-emitting unit) that emits near-infrared light (first infrared light), and a photodiode 34 (first light-receiving unit). The surface of the scale unit 31 facing the head unit 30 is provided with slits 33. The slits 33 have aluminum reflecting portions arranged at regular intervals. The near-infrared light emitted from the LED 32 is reflected by the slits 33 and then enters the photodiode 34. The optical encoder 15 can detect the position and amount of displacement by analyzing the electrical signal output from the photodiode 34.

[0027] The directivity of the near-infrared light emitted by the LED 32 of the head unit 30 is represented by the dashed line in Figure 11(a). The angle used to represent directivity is generally the beam angle (or half-value angle) θ, at which the output is reduced to half of the central beam with the highest output. Figure 11(b) is an example of the light distribution of the LED 32, showing that the output is 0.5 when the beam angle θ = 60°. The beam angle θ can be measured as a product-specific value using an illuminance meter that uses a photodiode, for example.

[0028] 10A, most of the near-infrared light emitted from the LED 32 at a directivity angle θ is irradiated onto the back surface of the scale unit 31 without entering the scale unit 31. Since near-infrared light is highly transparent, it is irradiated onto components arranged in front of the LED 32. However, the wavelength of the optical encoder 15 is not necessarily limited to the near-infrared region, as long as it is capable of detecting the line of sight.

[0029] 1, the head unit 30 and scale unit 31 of the optical encoder 15 are disposed near the driven lens 11. The head unit 30 is connected to a power supply means (not shown), and is therefore preferably fixed to a lens barrel structure or the like. The scale unit 31 is disposed on a frame 14 or the like that is driven in synchronization with the driven lens 11. This allows the position detection means to detect the position and amount of movement of the motor 18 and driven lens 11.

[0030] [Explanation of Locations for Arranging the Gaze Camera and Optical Encoder] Fig. 2 is a diagram illustrating locations in the HMD 100 where the gaze camera 16 and the optical encoder 15 can be placed. In Fig. 2, the horizontal axis represents the horizontal position of the HMD 100, the vertical axis represents the vertical position of the HMD 100, and the intersection of the coordinate axes is the center of the optical axis of the optical unit 20. The positive side of the horizontal axis represents the inside of the HMD 100, that is, the side closer to the user's nose. On the other hand, the negative side of the horizontal axis represents the outside, that is, the side farther from the user's nose.

[0031] In Figure 2(a), the gaze camera 16 is placed in the lower half of the range below the center of the optical axis. This is because the lower half is a suitable position for detecting gaze direction due to the structure of the human eye. As for the number of gaze cameras 16, one or two cameras are placed within the hatched area per optical unit 20, and it is well known that the greater the number, the higher the detection performance. The hatched area in Figure 2(a) is the area below the horizontal line passing through the optical axis of the optical unit 20, and is referred to as the gaze camera placement area 70.

[0032] In Figure 2(b), the optical encoder 15 is placed in the outer half of the range from the center of the optical axis. First, there is no space to place the motor 18 in Figure 1 inside where the nose is, so the motor is necessarily located on the outer side. Second, since placing the optical encoder 15 near the motor 18 allows for more accurate detection, the optical encoder 15 is also located on the outer side. The hatched area in Figure 2(b) is the area outside the vertical line passing through the optical axis of the optical unit 20 in the figure, and is called the optical encoder placement area 72.

[0033] 3 to 6 are diagrams for explaining the first to third embodiments of the present invention. These diagrams show the circumferential installation positions of the optical encoder 15 and the gaze camera 16 in the optical unit 20 for the left eye, projected onto a plane perpendicular to the optical axis of the optical unit 20. Arrows also indicate the optical axis directions in which the LED 32 of the optical encoder 15 and the image sensor 162 of the gaze camera 16 are oriented. For simplicity, the symbol "a" indicating the left eye side has been omitted.

[0034] In the figure, the illumination range of the LED 32 of the optical encoder 15 is represented by an arrow A indicating the illumination direction of the LED 32 and a directivity angle (half-value angle) θ indicating the directivity. Here, the arrow with the starting point of the illumination direction A of the LED 32 of the optical encoder 15 moved to the coordinate origin is defined as illumination direction A'. The direction in which the LED 32 is pointed is defined as the position detection direction. The position detection direction may be considered to be the direction of the central optical axis when the infrared light emitted from the LED 32 travels in a cone shape. Alternatively, the position detection direction may be considered to be the direction of the infrared light with the highest intensity among the infrared light emitted from the LED 32.

[0035] The direction in which the gaze camera 16 is pointed is defined as the gaze detection direction. The gaze detection direction may be considered to be the direction in which the installed gaze camera 16 can detect incident infrared light with the highest sensitivity. The gaze detection direction may also be the front direction set during the design of the gaze camera 16. In this case, the angle Φ is the angle between the irradiation direction A' (position detection direction) and the incident direction B (gaze detection direction) to the gaze camera 16.

[0036] Note that in this diagram, the distance from the optical axis of both devices is meaningless. Furthermore, in this application, of the regions divided into four by the coordinate axes in the diagram, the region where the X-axis and Y-axis values ​​are both positive is referred to as the first quadrant, and the quadrants are designated counterclockwise from there as the second to fourth quadrants. In the diagram, the first to fourth quadrants for the optical unit 20a for the left eye are indicated by symbols I to IV. When considering the optical unit 20b for the right eye, the X-axis is positive on the left side, which corresponds to the nose. The region where the X-axis and Y-axis values ​​are both positive is referred to as the first quadrant, and the quadrants are designated clockwise from there as the second to fourth quadrants.

[0037] First Embodiment FIG. 3 is a diagram illustrating a first embodiment. The optical unit 20 of this embodiment has one gaze camera 16. The optical encoder 15 is located in the second quadrant, and the gaze camera 16 is located near the X-axis, which is the boundary between the first and second quadrants. As shown in the figure, the LED 32 of the optical encoder 15 is located inside the lens barrel of the optical unit 20, that is, facing the center of the optical axis and facing the gaze camera 16. Near-infrared light has high transparency and passes through the lens barrel structure. However, in this embodiment, the relationship between the angle Φ between the irradiation direction A' and the incident direction B and the directivity angle θ is set to Φ > θ, thereby preventing errors.

[0038] If Φ<θ, the light illuminating the area inside the dashed line, i.e., the area less than the directivity angle θ, has a high output, and there is a risk that bright light spots will be captured as video information by the eye camera 16. Data containing such unnecessary video information may cause errors in post-processing. On the other hand, by setting Φ>θ as in this embodiment, the output of near-infrared light captured by the eye camera 16 can be kept within a low range, and therefore, the video information will be visualized as dark light spots. Therefore, this unnecessary video information can be easily excluded in post-processing.

[0039] (Modification) FIG. 4 is a diagram illustrating a modification of the first embodiment having one gaze camera 16. In this modification, the optical encoder 15 is placed in the second quadrant, and the gaze camera 16 is placed in the third quadrant. As shown in the figure, the magnitude relationship of the angle Φ between the irradiation direction A' and the incident direction B is Φ>θ. If the angle relationship is Φ>θ, the output of near-infrared light emitted from the LED 32 when it enters the gaze camera 16 can be kept within a low range. Therefore, even when both the optical encoder 15 and the gaze camera 16 are placed outside the Y axis, error occurrence can be prevented as in the first embodiment.

[0040] Second Embodiment Fig. 5 is a diagram illustrating a second embodiment. An optical unit 20 of this embodiment has a plurality of eye cameras 16. Description of parts having the same configuration and function as those of the first embodiment will be omitted.

[0041] As shown in the figure, an optical encoder 15 is disposed in the second quadrant. Furthermore, eye cameras 16 are disposed in the third and fourth quadrants. For convenience, the two eye cameras 16 are referred to as a first eye camera 16 (α) and a second eye camera 16 (β), respectively. In this case, if the optical encoder 15 is oriented toward the center of the optical axis as in the first embodiment, near-infrared light with a high output and a directivity angle θ or less may be incident on one of the two eye cameras 16, and may be captured as unnecessary video information.

[0042] Therefore, in this embodiment, the optical encoder 15 is positioned so that the direction of irradiation from the LED 32 of the optical encoder 15 is vertically upward. As a result, when the angle between the irradiation direction A' and the incident direction B1 of the first eye camera 16 (α) is Φ1, Φ1 > θ holds. Also, when the angle between the irradiation direction A' and the incident direction B2 of the second eye camera 16 (β) is Φ2, Φ2 > θ holds. This suppresses the intensity of near-infrared light incident on the eye camera 16, preventing errors from occurring.

[0043] 7 and 8 are diagrams showing the installation positions of the optical encoder 15 (head unit 30 and scale unit 31) and the gaze camera 16 in the optical axis direction projected onto a vertical plane including the optical axis of the optical unit 20 in the second embodiment shown in Fig. 5. In these diagrams, a plane perpendicular to the optical axis that passes near the LED of the head unit 30 of the optical encoder 15 is defined as a position detection plane P1. Furthermore, a plane perpendicular to the optical axis that passes through the image sensor 162 of the gaze camera 16 is defined as a gaze detection plane P2.

[0044] The position of the gaze detection plane P2 differs between Figures 7 and 8. In Figure 7, the gaze camera 16 is positioned closer to the eye than the driven lens 11. Therefore, the gaze camera 16 is not affected by changes in the focal length of the entire optical system due to movement of the driven lens 11. Therefore, this is a common configuration that is relatively easy technically; however, the gaze camera 16 protrudes toward the eye, resulting in a large optical unit 20. In this configuration, the gaze camera 16 faces the eye (right side of the figure) to capture the eye, and the position detection plane P1 is located behind the gaze camera 16. In other words, for the gaze camera 16 to capture the near-infrared light emitted from the head unit 30, the near-infrared light must reflect at least once. Because the light intensity decreases due to reflection, the configuration in Figure 7 is less likely to cause detection errors.

[0045] On the other hand, in Fig. 8, the gaze camera 16 is placed closer to the panel than the driven lens 11. As a result, the gaze camera 16 is affected by changes in the focal length of the entire optical system due to movement of the driven lens 11. Therefore, although this is a technically difficult configuration, the gaze camera 16 is embedded in an empty space near the display panel 10, which makes it possible to reduce the size of the optical unit 20. Since the size of the optical unit 20 has a large impact on the overall size of the HMD 100, and with the increasing demand for a smaller optical unit 20, Fig. 8 is a promising configuration.

[0046] In the configuration of Figure 8, the gaze camera 16 is facing the eye on the right side of the figure to capture an image of the eye, and the position detection plane P1 is on the front side of the gaze camera 16. In other words, there is a risk that near-infrared light emitted from the head unit 30 will directly enter the image sensor of the gaze camera 16. However, by arranging the LED 32 of the optical encoder 15 facing vertically upward as in the second embodiment of Figure 5, it is possible to prevent errors from occurring and to reduce the size of the optical unit 20.

[0047] 6 is a diagram illustrating a third embodiment. The optical unit 20 of this embodiment has two eye cameras 16. Descriptions of configurations and functions similar to those of the first and second embodiments will be omitted.

[0048] As shown in the figure, an optical encoder 15 is arranged in the third quadrant. Furthermore, eye cameras 16 are arranged in the third and fourth quadrants. For convenience, the two eye cameras 16 are referred to as a first eye camera 16 (α) and a second eye camera 16 (β), respectively.

[0049] In this embodiment, as shown in the figure, the LED 32 of the optical encoder 15 is arranged facing outward. For the first line of sight camera 16 (α) in the fourth quadrant, when the angle between the irradiation direction A' and the incident direction B1 is Φ1, the magnitude relationship of the angles is Φ1>θ, which prevents the occurrence of errors. This is the same as in the first and second embodiments.

[0050] On the other hand, for the second gaze camera 16 (β) in the third quadrant, when the angle between the illumination direction A' and the incident direction B2 is Φ2, Φ2<θ, which does not satisfy the condition for preventing error occurrence (Φ>θ). In this case, it is preferable to make the distance from the optical center of the optical encoder 15 to the LED 32 greater than the distance from the optical center of the gaze camera 16 to the image sensor 162. In other words, the distance from the optical axis in the position detection plane P1 to the LED 32 is greater than the distance from the optical axis in the gaze detection plane P2 to the image sensor 162. This causes the LED 32 to irradiate light from the rear side of the gaze camera 16, resulting in at least one reflection before the image sensor 162 captures the near-infrared light. Therefore, the intensity of the light incident on the image sensor 162 is low, preventing error occurrence.

[0051] Here, using FIG. 12 , we will generalize what is meant by the LED 32 facing outward in the third embodiment. FIG. 12 , expressed in the same way as FIG. 6 , is a diagram showing the irradiation direction A of the optical encoder 15 projected onto a plane perpendicular to the optical axis of the optical unit 20. Here, we consider a virtual circle C whose radius is the distance from the optical center (optical axis M) in the projection to the light source (starting point L of the light emission of the LED 32), and a tangent line T at the starting point L of the virtual circle C. The tangent line T is then divided into a first portion Ta and a second portion Tb, with the starting point L as the boundary. Furthermore, a first line segment LSa is drawn from the starting point L on the side opposite the virtual circle C, such that the angle between the first portion Ta and the tangent line T is θ. Furthermore, a second line segment LSb is drawn from the starting point L on the side opposite the virtual circle C, such that the angle between the second portion Tb and the tangent line T is θ. The angle between the first line segment LSa and the second line segment LSb is defined as a predetermined angle range R. If the directivity angle θ is 90° or more, the angle range R cannot be defined and the infrared light will travel backward from the light source. Therefore, the angle θ is defined as θ (θ<90°).

[0052] In this case, "outward" means that the direction of light emitted from the LED 32 is included in the angle range R. This angle range R can be defined at any position in the circumferential direction, and as long as the arrow A is within this angle range R, there is no need to consider the effect on the gaze camera 16.

[0053] On the other hand, the direction of the irradiation direction A described in the first embodiment shown in Fig. 3 and Fig. 4 and the second embodiment shown in Fig. 5 is "inward" rather than "outward." In Fig. 12, when the irradiation direction A is directed within a range not included in the angle range R, it is referred to as "inward."

[0054] In the first and second embodiments, even if the irradiation direction A is directed inward, the angle magnitude relationship is Φ>θ, so it is possible to prevent errors in gaze detection. To summarize the first to third embodiments, it is sufficient that (i) the position detection direction of the position detection means is included in the angle range R, or (ii) the position detection direction is not included in the angle range R, but the angle Φ between the position detection direction and the gaze detection direction is larger than the directivity angle θ.

[0055] As described above, according to the configuration of each embodiment, the light beam from the LED 32 of the optical encoder 15, which is the position detection means, does not directly enter the image sensor of the gaze camera 16, which is the gaze detection means. Therefore, even if the optical encoder 15 uses near-infrared light like the gaze camera 16, it does not affect the gaze detection results. Therefore, it is possible to provide an HMD 100 that can use the optical encoder 15 and the gaze camera 16 simultaneously.

[0056] The present invention is not limited to the above-described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to apprise the public of the scope of the present invention.

[0057] This application claims priority based on Japanese Patent Application No. 2024-099537, filed June 20, 2024, the entire contents of which are incorporated herein by reference.

[0058] [Configuration 1] A head-mounted image display device comprising: an optical unit having a display unit and an optical element; drive means for driving at least one of the display unit and the optical element; position detection means having a first light-emitting unit for emitting first infrared light and a first light-receiving unit for receiving the first infrared light irradiated from the first light-emitting unit, and for detecting a position of the drive means; and line-of-sight detection means having a second light-emitting unit for irradiating second infrared light and a second light-receiving unit for capturing the second infrared light irradiated from the second light-emitting unit and reflected by a user's eye, and for detecting the line of sight of the user, wherein the direction in which the first light-emitting unit of the position detection means is pointed is defined as a position detection direction, and a range of an angle θ (θ<90°) from the position detection direction is defined as a directivity angle, 1. An image display device comprising: a projection diagram in which the position detection means and the line-of-sight detection means are projected onto a plane orthogonal to the optical axis direction of the optical unit; a position where a virtual circle having a radius equal to the distance from the optical axis to the first light-emitting unit overlaps with the first light-emitting unit is defined as the origin of the first infrared light; a tangent to the virtual circle at the origin is divided into a first portion and a second portion with the origin as the boundary; a first line segment is drawn from the origin to the opposite side of the virtual circle such that the angle between the first portion is θ; a second line segment is drawn from the origin to the opposite side of the virtual circle such that the angle between the first line segment and the second portion is θ; and an angle between the first line segment and the second line segment is defined as an angle range R; (ii) the position detection direction of the position detection means is not included in the angle range R, and the angle formed by the position detection direction and the gaze detection direction, which is the direction in which the second light receiving unit of the gaze detection means is pointed, is larger than the directivity angle. [Configuration 2] The image display device according to Configuration 1, characterized in that, in the optical unit, when the user wears the image display device, the side closer to the user's nose is defined as the inside and the side farther from the user's nose is defined as the outside, in the projection view, the first light emitting unit of the position detection means is arranged outside a vertical line passing through the optical axis, and the second light receiving unit of the gaze detection means is arranged below a horizontal line passing through the optical axis.[Configuration 3] The image display device according to Configuration 1 or 2, comprising a plurality of the gaze detection means. [Configuration 4] The image display device according to any one of Configurations 1 to 3, wherein, in the projection diagram, the first light-emitting unit of the position detection means is arranged to irradiate the first infrared light vertically upward. [Configuration 5] The image display device according to Configuration 4, wherein, when a plane orthogonal to the optical axis direction and on which the first light-emitting unit of the position detection means is arranged is defined as a position detection plane, and a plane orthogonal to the optical axis direction and on which the second light-receiving unit of the gaze detection means is arranged is defined as a gaze detection plane, when the user wears the image display device, the gaze detection plane and the position detection plane are aligned in this order as seen from the display unit between the display unit of the optical unit and the user's eyes. [Configuration 6] The image display device according to any one of Configurations 1 to 5, wherein, in the projection diagram, the distance from the first light-emitting unit of the position detection means to the optical axis is greater than the distance from the second light-receiving unit of the gaze detection means to the optical axis.

[0059] 10: Display panel, 11: Driven lens, 13: Optical axis, 15: Position detection means, 16: Line-of-sight camera, 18: Motor, 20: Optical unit, 32: LED, 34: Photodiode

Claims

1. A head-mounted image display device comprising: an optical unit having a display unit and optical elements; drive means for driving at least one of the display unit and the optical elements; position detection means having a first light-emitting unit for emitting first infrared light and a first light-receiving unit for receiving the first infrared light irradiated from the first light-emitting unit, and for detecting the position of the drive means; and line-of-sight detection means having a second light-emitting unit for irradiating second infrared light and a second light-receiving unit for capturing the second infrared light irradiated from the second light-emitting unit and reflected by the user's eye, and for detecting the line of sight of the user; wherein the direction in which the first light-emitting unit of the position detection means is pointed is defined as the position detection direction, and the range of an angle θ (θ<90°) from the position detection direction is defined as the directivity angle; In a projection diagram in which the position detection means and the line of sight detection means are projected onto a plane perpendicular to the optical axis direction of the optical unit, a position where an imaginary circle having a radius equal to the distance from the optical axis to the first light-emitting unit and the first light-emitting unit overlap is defined as the origin of the first infrared light, and a tangent to the imaginary circle at the origin is divided into a first portion and a second portion with the origin as the boundary, a first line segment is drawn from the origin to the opposite side of the imaginary circle so that the angle between the first portion is θ, and a second line segment is drawn from the origin to the opposite side of the imaginary circle so that the angle between the first line segment and the second portion is θ, and an angle between the first line segment and the second line segment is defined as an angle range R, the following (i) or (ii) is satisfied: (i) the position detection direction of the position detection means is included in the angle range R. (ii) The position detection direction of the position detection means is not included in the angle range R, and the angle formed by the position detection direction and the gaze detection direction, which is the direction in which the second light receiving unit of the gaze detection means is pointed, is larger than the directivity angle.

2. The image display device according to claim 1, characterized in that, in the optical unit, when the user wears the image display device, the side closer to the user's nose is defined as the inside and the side farther from the user's nose is defined as the outside, in the projection view, the first light-emitting unit of the position detection means is positioned outside a vertical line passing through the optical axis, and the second light-receiving unit of the line-of-sight detection means is positioned below a horizontal line passing through the optical axis.

3. The image display device according to claim 1 or 2, characterized in that it comprises a plurality of said line-of-sight detection means.

4. An image display device according to claim 1 or 2, characterized in that in the projection view, the first light-emitting unit of the position detection means is arranged so as to irradiate the first infrared light vertically upward.

5. The image display device according to claim 4, characterized in that when a plane perpendicular to the optical axis direction and on which the first light-emitting unit of the position detection means is arranged is defined as a position detection plane, and a plane perpendicular to the optical axis direction and on which the second light-receiving unit of the gaze detection means is arranged is defined as a gaze detection plane, when the user wears the image display device, the gaze detection plane and the position detection plane are aligned in this order as seen from the display unit between the display unit of the optical unit and the user's eyes.

6. An image display device as described in claim 1 or 2, characterized in that in the projection view, the distance from the first light-emitting element of the position detection means to the optical axis is greater than the distance from the second light-receiving element of the line-of-sight detection means to the optical axis.

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