JP3624112B2 - Auto focus glasses - Google Patents

Description

として計算される。
【００１５】
両眼の視線方向を検知する方法としては種々の眼球運動計測法が開発されており、それらが用いているものと同様の原理に基づて実現できる。しかし、本発明による自動焦点調節型眼鏡を実現するための視線方向の検知装置にはより簡便で小型軽量であることが望ましい。また、本発明による自動焦点調節型眼鏡は装着が簡便でしかも人間の動作を制限しないものであることが望ましい。したがって、本発明において採用する両眼視線検出法も非接触で小型軽量であることが望ましく、それを実現できる代表的な方法としては、まず第一に、光学的方法がある。
【００１６】
＜光学的方法＞
光学的に両眼視線方向を検出する方法としては、瞳孔の位置を検出して視線方向を検知する方法がある。この方法によって視線方向を検出する装置も製品化されている。図６はこの方法を説明する図である。
図６（ａ）において、ＣＣＤカメラ等の撮像器６２２および６２４を用いて眼球部分（黒目）を画像として取り込む（図６（ｂ）参照）。取り込んだ画像を、図６（ｃ）に示すような画像の明暗を利用した画像処理技術を用いて、暗い部分である瞳孔部分を抽出して、その位置を検出するものである。この方法は、撮像手段が大きくなること、および撮像時間、画像処理時間などのため眼球の高速な運動を検知できないなどの改良すべき課題が残されている。
【００１７】
同様な構成で、視野内にある輝点像の位置を高速に検知できる検出素子として半導体像位置検出素子（ＰＳＤ）がある（例えば、特開平６−１０４８６１号公報参照）。この検出素子においては、輝点像が投射された位置において生成された光電流を分割抵抗に流入させ、その両端に設けられた電極からの出力信号を演算することによって輝点像の重心的位置を高速に得ることができる。従って、眼球の像から半導体像位置検出素子（ＰＳＤ）を用いて、瞳孔部分の位置を検出することができる。
【００１８】
また、ＰＳＤを改良したものとして、複眼式半導体像位置検出素子（Ｄｉｒｅｃｔｉｏｎ Ｓｅｎｓｉｔｉｖｅ Ｄｅｖｉｃｅ：ＤＳＤ）を用いた方法がある。ＤＳＤは、マイクロレンズと微少ＰＳＤとを組み合わせたものを多数配列し、微少ＰＳＤの出力が加算されて出力されるように構成されている（例えば、特開昭７−２８６８１３号公報参照）。これにより、光学系を小さくしても、等価的にレンズの開口がマイクロレンズの開口部の合計となるようにして、レンズ系を小さくすることによるＳ／Ｎ比の低下を回避している。瞳孔の位置検出は、前述のＰＳＤと同様に行うことができる。
【００１９】
さらに、このＰＳＤ原理にしたがって視野中にある暗点像を高速に検出できる素子が、本発明の発明者により考案されている（特願平１０−３３０３６２号出願参照）。この素子を用いることにより、瞳孔の暗い部分の重心的な位置を高速に検出できる。半導体暗点像検出素子を図７（ａ）を用いて説明する。図７（ａ）において、半導体暗点像検出素子９００は、入射光に応じた光電流を生成する光電素子９２０、光電素子で生成された光電流が光投射位置に対応して流入する負荷抵抗９１０、負荷抵抗に流入する電流分布がほぼ一様になるように、光電流の不足分を補充するために分割抵抗９４０とダイオード９３０から構成されている。実際の構造では、光電素子９２０、負荷抵抗９１０、ダイオード９３０、および分割抵抗９４０はそれぞれ層構造を有し、全体として多層構造となっている。光電流の不足分を補充するための手段が分割抵抗９４０の光電素子の位置に対応した部分から供給され（図７（ｂ）参照）、その光電流の不足分を補充する電流が分割抵抗９４０上の光電素子９２０の位置に対応した部分と両端の信号電極間の抵抗値に応じて分配される。それが補充電流供給区間全域にわたり加え合わされた電流として、分割抵抗９４０の両端より信号電流として出力（供給）されるように構成される。検出された信号電流を従来のＰＳＤにおけると同じように演算処理することによって、明るい背景中の暗い像の位置を検出できる。すなわち、補充電流を供給する分割抵抗の抵抗率が一様であるとすると、抵抗値は端子との間の距離に比例するので光の入射位置ｘの情報（中心位置からのずれ率に相当）は次式で求められる。
【数２】

この式により、光電素子に与えられた眼の像から暗い部分（瞳孔部分）が検出できる。
【００２０】
他の光学的な検出方法としては、図８に示したプルキンエ像を用いた方法がある。眼球は白目（強膜）と黒目（角膜）の部分に分かれている。角膜部分は、ガラス面と同様で透明体であり、光に対しては鏡面としての作用する。プルキンエ像とは、眼の外部にある光源（例えば、図８に示したＬＥＤ８２０）が角膜を鏡として映されて眼球内にあるように見える輝点像のことである。図８に示されているように、眼球においては、眼球の回転中心に対して角膜表面の中心が偏心している。このため、眼球の向きが変化すると鏡に相当する面が回転し、プルキンエ像の位置が眼球の向きに対応して移動する。この移動を像位置検出器８３０により検出することにより、眼球の向きすなわち視線方向を検出することができる。この像位置検出器には、上述で説明した検出器（例えばＰＳＤ等）を用いることができる。
【００２１】
上述のように、視線方向の検出を光学的に行うためには、瞳孔位置およびプルキンエンエ像の位置を検出して行うことができる。その他にも、白目と瞳孔境界位置や、コンタクトをはめ、それに付されたマーク位置を検知することによっても、視線方向を検出することができる。
【００２２】
＜筋電を検知する方法＞
眼球は、眼球の周りにある筋肉を用いて動いている。図９（ａ）はこの眼球の周りの筋肉について示している。この眼球運動を生成する筋肉の動きは、動くと発生する皮膚電位を検出することにより検出できるので、この皮膚電位を検出することにより眼球の動きを推定することができる。図９（ｂ）は、この皮膚電位の検出を示している。図９（ｂ）において、眼鏡の内側に複数の電極８１２，８１４，８１６，８１７を取り付け、この電極により、その部分の皮膚電位を検出する。通常は、眼球の左右に取り付けた電極からの信号の差が、眼球の動きの向きに応じて変化する。このため、予め既知の位置を凝視して、この位置との相対的な位置を筋肉の動きを検出することで眼球の向きを推定する。
【００２３】
＜レンズの焦点距離を変化させる方法＞
可変焦点型レンズについてもいろいろな方法がある。周知である方法としては、光学レンズの位置を変化させる方法である。本発明の自動焦点調節型眼鏡の実現には小型軽量で応答速度が速いことが望まれ、それらの点でこの方法はそれほど好ましいものではないが、この方法によって、眼鏡を構成するレンズの焦点距離変えることにより、本発明を実現できる。
【００２４】
＜レンズの形状を変化させる型の方法＞
人間の眼球においては水晶体の厚さを変化させることによって焦点調節が行なわれている。以下においては眼球の水晶体におけると同様あるいはそれに類するような原理、すなわち、レンズ形状を変化させる型の方法による可変焦点レンズの実現法を、図１０に示すことにする。
【００２５】
図１０において、２つの透明な板状対象物３０２の間に、外部環境媒体（すなわち空気）の屈折率と異なる屈折率を有する変形可能な透明体３０４を充満するように介在させ、２つの板状対象物３０２の表面形状及び変形可能な透明体３０４の形状をアクチュエータ３０６により変化させて、２つの板状対象物３０２を通過する光の屈折状態を変化させる。
【００２６】
焦点距離を変化させるためには、例えば透明体３０４を液体等の流動体で構成し、そのアクチュエータ３０６により、流動体を密閉した板状対象物３０２の間に送り込むことを行えばよい。
【００２７】
この図１０に示した可変焦点レンズについて、特にアクチュエータ３０６により板状対象物等を変化させる他の方法等については、同日に出願した同じ発明者による特許出願を参照されたい。
焦点を変化させる他の方法には、例えば、圧電体で構成した板状対象物を変形させる、アクチュエータの厚みを変化させる等がある。
【００２８】
＜立体視への応用＞
図２で示したように、両眼立体視により３次元対象物を表示する場合などに、立体が見える位置までの距離と画面までの距離が異なるため人間の目にとって焦点調節が不自然な状態、すなわち両眼の輻輳と焦点調節との間でも矛盾が生じる。このため、長時間立体視を行うと所謂「立体視酔い」とか「ＶＲ酔い」などと呼ばれる状態となりひどい場合には頭痛や吐き気をもようすことがある。このような場合に視線方向を検知し、それに応じて結果的に焦点が自然に画面上に合うように調整することにすれば、従来の立体視システムに比べてより自然な形態で、「立体視酔い」を著しく軽減できるステレオ視システムが実現される。これを図１１を用いて説明する。
【００２９】
図１１において、図３と同様に、左眼および右眼の視線方向検出器２２２および２２４と、焦点距離を変化できる可変焦点レンズ２４２および２４４は、本発明の自動焦点調節眼鏡を構成している。レンズ２３２および２３４は、それぞれ眼鏡の主レンズで、必要があれば、可変焦点レンズ２４２および２４４と組み合わされてレンズ系を構成している。
【００３０】
さて、スクリーン１４０上の立体視用の画像をみて立体視を行い、１３０にその立体画像が見えているとする。このような場合に、立体視画像１３０を見ている視線方向を検知し、それに応じて結果的に焦点がスクリーン１４０上に合うように調整する。このように眼鏡の焦点距離を調節して、眼の焦点が立体視画像１３０に合わせられていても、実際に見る必要のあるスクリーン１４０上に焦点を合わせることができる。これにより、両眼の輻輳と焦点調節との間の矛盾による「立体視酔い」を著しく軽減できる。
【００３１】
【発明の効果】
上記の説明のように、本発明においては、人間が見ようとする距離にある対象物に容易に焦点を合わせられる様に、焦点調節可能なレンズ系の焦点距離を注視点距離に応じて変化させることができる。
【００３２】
そのため、たとえばオフィスにおける事務作業や工業における組立作業等の様に、腕が届く程度の範囲での作業において、近い対象物および離れた対象物を明瞭に観察し判断して操作するような場合に、老眼の人でも眼鏡を掛け替える必要がなく、作業効率を著しく高めることができる。
さらに、両眼立体視により３次元対象物を表示する場合に、長時間立体視を行うと生じる所謂「立体視酔い」とか「ＶＲ酔い」を防ぐためも使用することができる。
【図面の簡単な説明】
【図１】眼において、老眼鏡が必要となることを説明する図である。
【図２】立体視において、「立体視酔い」が起きる原因を説明する図である。
【図３】本発明の自動焦点調節眼鏡の構成を説明する図である。
【図４】本発明の自動焦点調節眼鏡の制御系を説明するブロック図である。
【図５】視線方向から焦点距離を算出することを説明する図である。
【図６】ＰＳＤ等による眼の位置検出を説明する図である。
【図７】半導体暗点像検出素子による眼の位置検出を説明する図である。
【図８】プルキンエ像による視線方向検出を説明する図である。
【図９】皮膚電位により視線方向検出を説明する図である。
【図１０】可変焦点レンズの構成を説明する図である。
【図１１】立体視への応用を説明する図である。
【符号の説明】
１１０ 左眼
１２０ 右眼
１３０ 立体視画像
１３２ 左眼用画像
１３４ 右眼用画像
１４０ スクリーン
２００ 自動焦点調節眼鏡
２２２，２２４ 視線方向検出器
２３２，２３４ レンズ
２４２，２４４ 可変焦点レンズ
２５０ 注目点
３０２ 板状対象物
３０４ 透明体
３０６ アクチュエータ
５２０ 算出部
５２０ 注視点距離算出部
５３０ 焦点距離制御部
６２２，６２４ 画像撮像器
８１２，８１４，８１６，８１７ 電極
８３０ 像位置検出器
９００ 半導体暗点像検出素子
９１０ 負荷抵抗
９２０ 光電素子
９３０ ダイオード
９４０ 分割抵抗[0001]
BACKGROUND OF THE INVENTION
The present invention relates to automatic focusing glasses capable of changing a focal length according to a gaze point distance.
[0002]
[Background]
In the human eyeball, the thickness of the crystalline lens changes according to the distance of the object to be watched, and a clear image is projected on the retina (FIG. 1 (a) I). However, in the case of hyperopia (FIG. 1 (a) II) or myopia (FIG. 1 (a) III), an image cannot be projected on the retina.
[0003]
In addition, the adjustable range of the lens thickness becomes narrower with age. For this reason, the distance of the object to be seen in daily life often exceeds the focus adjustable range, making various operations difficult. Glasses are used to compensate for the focus adjustment ability of the eyeball (see FIG. 1B).
[0004]
When a nearsighted person becomes old and the focus adjustment range is narrowed, a method of selectively using two types of glasses for near vision and far vision is used. In addition, the upper region of the spectacle lens is used for far vision and the lower region is used for near vision, with different lens focal lengths in one lens. This method is used to change the distance and for near vision and for near vision.
[0005]
When a human focuses on an object in the natural environment, there is a one-to-one relationship between absolute distance and focus adjustment. Convergence angle is an angle when the eye looks at an object is, since the absolute distance and inversely proportional to the object, the angle of convergence and focusing is also in one-to-one relationship. Therefore, the convergence angle is one of the cues for distance sense or focus adjustment. For this reason, it is considered that the mismatch between the angle of convergence and the focal length causes visual burden and fatigue. However, in the case of stereoscopic viewing, the consistency between the sense of distance obtained from an object viewed stereoscopically and the convergence angle cannot be obtained. This will be described with reference to FIG. In FIG. 2, the left eye image 132 and the right eye image 134 are viewed with the left eye 110 and the right eye 120, respectively, and the stereoscopic image 130 of the image is viewed. The right eye 120 and the left eye 110 are focused on the images 132 and 134, but the stereoscopic image 130 is seen in front of the images, and the sense of distance is the same as the convergence angle and the focal length that the eyes actually match. Do not fit. Such inconsistency can cause “stereoscopic sickness”, “VR sickness”, and the like.
[0006]
[Problems to be solved by the invention]
In the method of selectively using two kinds of glasses, it is difficult to continue the work when both hands are used for the work. In addition, in the case where the near vision lens and the far vision lens are incorporated in one lens, the movement of the line of sight with respect to the spectacle lens and the head movement for correcting the line of sight to match the gaze point are required. In the case of work that is carried out by concentrating consciousness continuously, it is often accompanied by difficulties such as trouble in the work.
Furthermore, it cannot be applied to the purpose of reducing stereoscopic sickness by eliminating the contradiction between binocular convergence and focus adjustment that occurs when a three-dimensional object is displayed by binocular stereoscopic vision.
[0007]
The object of the present invention is to detect the distance to the gazing point with both eyes in order to alleviate such difficulties in work that requires near vision and far vision, and automatically adjust the lens focal length accordingly. An object of the present invention is to realize a spectacle that can assist a focus adjustment function so that a clear image can be observed over both the distance and near vision ranges without performing eyeglass exchange, intentional line-of-sight movement, and head movement.
Furthermore, when displaying a three-dimensional object by binocular stereoscopic vision, etc., the contradiction between binocular convergence and focus adjustment can be alleviated, and more natural morphological observation can be performed compared to conventional stereo vision systems. It is also an object of the present invention to realize a stereo vision system that can remarkably reduce “stereoscopic sickness” and “VR sickness”.
[0008]
[Means for Solving the Problems]
In order to solve the above problem, in the present invention, means for detecting which direction each eye is facing and estimating information on the distance to the position where both eyes are gazing and a lens capable of adjusting the focal length And a focal length of the lens system is automatically adjusted according to the detected distance information to the gazing point.
[0009]
If the direction in which both eyes are facing, that is, the direction of the line of sight is detected, the distance to the position where the eyes are observed as the point where the lines of sight of both eyes intersect can be estimated. If the distance to the position where both eyes are gazing is known, the focal length of the variable focal length lens can be adjusted accordingly so that the object at the gazing point position can be seen clearly. Therefore, it is possible to always clearly observe the image of the object at the position where both eyes are gazing.
[0010]
In the case of stereo display, it is natural for human vision to focus on the point of sight, that is, the position where the binocular line of sight intersects. Therefore, the variable focal length lens is adjusted so that the position where the image is displayed is naturally focused and the amount of deviation from the observable position is corrected, and the image is observed as a clear image in a natural state. it can.
[0011]
According to the present invention, according to the distance at which both eyes are gazing, the spectacles are exchanged from the far vision to the near vision over the range where the near vision glasses are necessary to the near vision glasses. In addition, it is possible to clearly observe the image of the object at the position of the gazing point without intentionally changing the line-of-sight direction of both eyes and the posture of the head. Therefore, it is possible to perform a natural and efficient work when the work requires both the far vision glasses and the near vision glasses.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
FIG. 3 and FIG. 4 are conceptual diagrams of the configuration of the automatic focusing glasses realized based on the present invention. As shown in FIG. 3, the automatic focusing glasses 200 of the present invention are composed of left and right eye gaze direction detectors 222 and 224 and variable focus lenses 242 and 244 that can change the focal length. The lenses 232 and 234 are the main lenses of the glasses, and if necessary, are combined with the variable focus lenses 242 and 244 to form a lens system. FIG. 4 shows a control system of the automatic focusing glasses 200 of the present invention. In FIG. 4, the left-eye and right-eye gaze direction signals obtained from the left-eye and right-eye gaze direction detectors 222 and 224 are output to the gaze point distance calculation unit 520, respectively. The gaze point distance calculation unit 520 calculates the gaze point (250 in FIG. 3) that both eyes are looking at based on the input gaze direction signal, and calculates the focal length of the lens system of the glasses. Based on this, a control signal to the variable focus lenses 242 and 244 is generated in the focal length control unit 530 of the lens system. The variable focus lenses 242 and 244 are controlled by the control signal generated by the focal length control unit 530, and the distance to the gazing point is set as the focal length of the lens system constituting the glasses.
[0013]
There are various methods for realizing the above-described components such as the gaze direction detector. Therefore, since the embodiment of the present invention can be realized as a combination of these, the types thereof are extremely various. In the following, first, an implementation method for each of these components will be described, and one embodiment configured as a combination thereof will be described in detail.
[0014]
<Gaze direction detection>
FIG. 5 is a diagram for explaining the calculation of the distance to the point of interest. As shown in FIG. 5, the gaze point can be estimated by calculating the position where the line of sight of both eyes intersects if the direction in which the binocular eyeballs face, that is, the line of sight direction can be detected. That is, when the distance between the left eye 110 and the right eye 120 is d and the angles indicating the line-of-sight direction are θL and θR, the distance L from the eye to the point of interest 250 is
[Expression 1]

Is calculated as
[0015]
Various eye movement measurement methods have been developed as methods for detecting the line-of-sight direction of both eyes, and can be realized based on the same principle as those used. However, it is desirable that the gaze direction detecting device for realizing the autofocusing glasses according to the present invention be simpler, smaller and lighter. In addition, it is desirable that the auto-focusing glasses according to the present invention are easy to wear and do not restrict human movement. Therefore, it is desirable that the binocular line-of-sight detection method employed in the present invention is also non-contact, small and light, and a representative method capable of realizing it is, first of all, an optical method.
[0016]
<Optical method>
As a method for optically detecting the binocular line-of-sight direction, there is a method for detecting the line-of-sight direction by detecting the position of the pupil. Devices that detect the line-of-sight direction by this method have also been commercialized. FIG. 6 is a diagram for explaining this method.
In FIG. 6A, an eyeball portion (black eye) is captured as an image using imagers 622 and 624 such as a CCD camera (see FIG. 6B). A captured pupil image is extracted by using an image processing technique using the brightness of the image as shown in FIG. 6C, and the position of the pupil is detected. This method still has problems to be improved, such as the fact that the imaging means becomes large and high-speed movement of the eyeball cannot be detected due to imaging time, image processing time, and the like.
[0017]
There is a semiconductor image position detecting element (PSD) as a detecting element capable of detecting the position of a bright spot image in the field of view at high speed with the same configuration (see, for example, Japanese Patent Laid-Open No. 6-104861). In this detection element, the photocurrent generated at the position where the bright spot image is projected flows into the dividing resistor, and the output signal from the electrodes provided at both ends thereof is calculated, thereby calculating the barycentric position of the bright spot image. Can be obtained at high speed. Therefore, the position of the pupil portion can be detected from the image of the eyeball using the semiconductor image position detecting element (PSD).
[0018]
Further, as an improvement of PSD, there is a method using a compound eye type semiconductor image position detection element (Direction Sensitive Device (DSD)). The DSD is configured so that a large number of combinations of microlenses and micro PSDs are arranged and the outputs of micro PSDs are added and output (for example, see Japanese Patent Application Laid-Open No. 7-286813). As a result, even if the optical system is made smaller, the lens aperture is equivalently the sum of the apertures of the microlens, so that a reduction in the S / N ratio due to the smaller lens system is avoided. The detection of the position of the pupil can be performed in the same manner as the PSD described above.
[0019]
Furthermore, an element capable of detecting a dark spot image in the visual field at high speed according to the PSD principle has been devised by the inventor of the present invention (see Japanese Patent Application No. 10-330362). By using this element, the center-of-gravity position of the dark part of the pupil can be detected at high speed. The semiconductor dark spot image detection element will be described with reference to FIG. In FIG. 7A, a semiconductor dark spot image detecting element 900 includes a photoelectric element 920 that generates a photocurrent according to incident light, and a load resistance in which the photocurrent generated by the photoelectric element flows in corresponding to the light projection position. 910, a dividing resistor 940 and a diode 930 are used to supplement the shortage of the photocurrent so that the current distribution flowing into the load resistor becomes substantially uniform. In an actual structure, each of the photoelectric element 920, the load resistor 910, the diode 930, and the dividing resistor 940 has a layer structure, and has a multilayer structure as a whole. A means for replenishing the shortage of the photocurrent is supplied from the portion of the dividing resistor 940 corresponding to the position of the photoelectric element (see FIG. 7B), and the current for replenishing the shortage of the photocurrent is supplied to the dividing resistor 940. Distribution is performed according to the resistance value between the portion corresponding to the position of the upper photoelectric element 920 and the signal electrodes at both ends. It is configured to be output (supplied) as a signal current from both ends of the dividing resistor 940 as a current added over the entire supplementary current supply section. By computing the detected signal current in the same way as in a conventional PSD, the position of a dark image in a light background can be detected. That is, assuming that the resistivity of the dividing resistor that supplies the supplementary current is uniform, the resistance value is proportional to the distance from the terminal, and therefore information on the light incident position x (corresponding to the deviation rate from the center position). Is obtained by the following equation.
[Expression 2]

By this formula, a dark part (pupil part) can be detected from the eye image given to the photoelectric element.
[0020]
As another optical detection method, there is a method using the Purkinje image shown in FIG. The eyeball is divided into white eyes (sclera) and black eyes (cornea). The cornea portion is a transparent body similar to the glass surface, and acts as a mirror surface for light. The Purkinje image is a bright spot image in which a light source (for example, LED 820 shown in FIG. 8) outside the eye is reflected in the cornea as a mirror and appears to be in the eyeball. As shown in FIG. 8, in the eyeball, the center of the cornea surface is decentered with respect to the center of rotation of the eyeball. For this reason, when the direction of the eyeball changes, the plane corresponding to the mirror rotates, and the position of the Purkinje image moves corresponding to the direction of the eyeball. By detecting this movement by the image position detector 830, the direction of the eyeball, that is, the line-of-sight direction can be detected. The detector (for example, PSD etc.) demonstrated above can be used for this image position detector.
[0021]
As described above, in order to optically detect the line-of-sight direction, the pupil position and the position of the Purkinje image can be detected. In addition, the line-of-sight direction can also be detected by detecting a boundary position between the white eye and the pupil, a contact, and a mark position attached thereto.
[0022]
<Method for detecting myoelectricity>
The eyeball moves using muscles around the eyeball. FIG. 9A shows the muscles around the eyeball. Since the movement of the muscle that generates the eye movement can be detected by detecting the skin potential generated when the eye moves, the movement of the eye can be estimated by detecting the skin potential. FIG. 9B shows the detection of this skin potential. In FIG. 9B, a plurality of electrodes 812, 814, 816, and 817 are attached to the inner side of the glasses, and the skin potential of that portion is detected by these electrodes. Usually, the difference in signal from the electrodes attached to the left and right of the eyeball changes according to the direction of movement of the eyeball. Therefore, the direction of the eyeball is estimated by staring at a known position in advance and detecting the movement of the muscle relative to this position.
[0023]
<Method of changing the focal length of the lens>
There are various methods for variable focus lenses. A well-known method is a method of changing the position of the optical lens. In order to realize the auto-focusing glasses of the present invention, it is desired that the glasses are small and light, and the response speed is high. In this respect, this method is not so preferable. By changing, the present invention can be realized.
[0024]
<Method of mold to change lens shape>
In the human eyeball, focus adjustment is performed by changing the thickness of the crystalline lens. In the following, the principle similar to or similar to that in the crystalline lens of the eyeball, that is, a method for realizing a variable focus lens by a method of changing the lens shape will be shown in FIG.
[0025]
In FIG. 10, two plates are interposed between two transparent plate-like objects 302 so as to be filled with a deformable transparent body 304 having a refractive index different from that of the external environment medium (ie, air). The surface shape of the object 302 and the shape of the deformable transparent body 304 are changed by the actuator 306 to change the refraction state of the light passing through the two plate objects 302.
[0026]
In order to change the focal length, for example, the transparent body 304 may be formed of a fluid such as a liquid, and the fluid may be fed between the sealed plate-like objects 302 by the actuator 306.
[0027]
Regarding the variable focus lens shown in FIG. 10, in particular, for other methods for changing the plate-like object or the like by the actuator 306, refer to the patent application filed by the same inventor filed on the same day.
Other methods for changing the focus include, for example, deforming a plate-like object formed of a piezoelectric body, changing the thickness of an actuator, and the like.
[0028]
<Application to stereoscopic vision>
As shown in FIG. 2, when displaying a three-dimensional object by binocular stereoscopic vision, the focus adjustment is unnatural for the human eye because the distance to the position where the stereoscopic can be seen and the distance to the screen are different. That is, there is also a contradiction between binocular convergence and focus adjustment. For this reason, when stereoscopic vision is performed for a long time, a so-called “stereoscopic sickness” or “VR sickness” occurs, and in severe cases, headache or nausea may occur. In such a case, if the gaze direction is detected and the focus is adjusted so that the focus is naturally adjusted on the screen as a result, the “stereoscopic” has a more natural form compared to the conventional stereoscopic system. A stereo vision system that can significantly reduce “visual sickness” is realized. This will be described with reference to FIG.
[0029]
In FIG. 11, as with FIG. 3, the left-eye and right-eye gaze direction detectors 222 and 224 and the variable focus lenses 242 and 244 capable of changing the focal length constitute the auto-focusing glasses of the present invention. . The lenses 232 and 234 are the main lenses of the glasses, and if necessary, are combined with the variable focus lenses 242 and 244 to form a lens system.
[0030]
Now, it is assumed that the stereoscopic image on the screen 140 is viewed and the stereoscopic image is seen at 130. In such a case, the direction of the line of sight in which the stereoscopic image 130 is viewed is detected, and as a result, the focus is adjusted to be on the screen 140. By adjusting the focal length of the glasses in this way, even when the eye is focused on the stereoscopic image 130, it is possible to focus on the screen 140 that actually needs to be viewed. Thereby, the “stereoscopic sickness” due to the contradiction between the convergence of both eyes and the focus adjustment can be remarkably reduced.
[0031]
【The invention's effect】
As described above, in the present invention, the focal length of the lens system that can be adjusted is changed in accordance with the gaze point distance so that an object at a distance to be seen by a human can be easily focused. be able to.
[0032]
For this reason, when working within a range where the arm can reach, such as office work in the office or assembly work in industry, etc., when a close object and a distant object are clearly observed, judged and operated. Even presbyopic people do not need to change their glasses, and work efficiency can be significantly increased.
Furthermore, when displaying a three-dimensional object by binocular stereoscopic vision, it can also be used to prevent so-called “stereoscopic sickness” or “VR sickness” that occurs when stereoscopic vision is performed for a long time.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining that reading glasses are necessary for eyes.
FIG. 2 is a diagram for explaining the cause of “stereoscopic sickness” in stereoscopic vision;
FIG. 3 is a diagram illustrating a configuration of automatic focusing glasses according to the present invention.
FIG. 4 is a block diagram illustrating a control system of the automatic focusing glasses according to the present invention.
FIG. 5 is a diagram for explaining calculation of a focal length from a line-of-sight direction.
FIG. 6 is a diagram for explaining eye position detection by PSD or the like.
FIG. 7 is a diagram for explaining eye position detection by a semiconductor dark spot image detection element;
FIG. 8 is a diagram for explaining gaze direction detection based on a Purkinje image.
FIG. 9 is a diagram illustrating gaze direction detection based on skin potential.
FIG. 10 is a diagram illustrating a configuration of a variable focus lens.
FIG. 11 is a diagram illustrating application to stereoscopic vision.
[Explanation of symbols]
110 Left eye 120 Right eye 130 Stereoscopic image 132 Left eye image 134 Right eye image 140 Screen 200 Automatic focusing glasses 222 and 224 Gaze direction detectors 232 and 234 Lenses 242 and 244 Variable focus lens 250 Attention point 302 Plate shape Object 304 Transparent body 306 Actuator 520 Calculation unit 520 Gaze point distance calculation unit 530 Focal length control unit 622, 624 Image pickup device 812, 814, 816, 817 Electrode 830 Image position detector 900 Semiconductor dark spot image detection element 910 Load resistance 920 Photoelectric element 930 Diode 940 Split resistance

Claims (2)

Means for detecting the position of the eyes of both eyes by detecting the position of the eyes of both eyes, using a semiconductor dark spot image detecting element that detects a dark portion against a bright background, and a distance to a position to be watched with both eyes;
A lens with adjustable focal length,
A focal length adjusting means for adjusting a focal length of the lens system based on the detected distance information;
The semiconductor dark point image detection element, a photoelectric element which light to generate a photocurrent corresponding to the intensity of incident light at the incident portion, the incident position the photocurrent generated is the light at the photoelectric elements replenishment inflow load resistor flowing correspondingly, the shortage of current in the photocurrent as the distribution of current flowing to the load resistance corresponding to the incident position of the light is substantially uniform over the entire detection range A split resistor and a diode disposed corresponding to the photoelectric element , and signal electrode ends disposed at both ends of the split resistor, for supplementing the shortage of the photocurrent A current is supplied from a portion of the dividing resistor corresponding to a position where the photocurrent flows into the load resistor, and a current for supplementing the shortage of the photocurrent is insufficient for the photocurrent on the dividing resistor. Of current to replenish the minute Are distributed at a ratio corresponding to the resistance value between the signal electrode terminal and feeding portion, is outputted from the signal electrode end as added combined current over supply interval entire current to replenish the shortage of the photocurrent This is an automatic focusing type eyeglass. In the automatic focusing glasses according to claim 1,
The lens capable of adjusting the focal length is interposed between two transparent plate-like objects so as to be filled with a deformable transparent body having a refractive index different from the refractive index of the external environment medium. By changing the thickness of the actuator provided on the surface, the surface shape of the two plate-like objects and the deformable transparent body shape are changed to change the refractive state of the light passing through the two plate-like objects. An auto-focusing spectacle that is a focusing lens.

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