JPH0337039A - Optical apparatus with visual line-detecting device - Google Patents

Abstract

PURPOSE:To prevent the finder visual field from being disturbed and improve a one's visual line-detecting precision by providing a means specifying the effective light flux region of a finder optical system on an ocular. CONSTITUTION:A one's visual line-detecting optical system is constituted of an image forming lens 2, an image sensor 1 and an eyeball illuminating infrared light emitting diode 4 arranged above an ocular 5. The infrared light emitting diode 4 is arranged on the side of the image forming lens 2, and infrared rays are reflected on the dichroic mirror of the ocular 5 and diffusively illuminate an eyeball 3. The upper face A of the dichroic mirror section of the ocular 5 is made wider than the region required to pass the finder effective light flux by this arrangement, and the outgoing face B of its part is made wide accordingly. A limiting block 6 shielding the outside from the finder effective light flux is provided on the finder light flux incidence face of the ocular 5, the observable finder light flux is set the same as before, and the moving range of the eye point of an observer is kept the same as before.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application in Business A] The present invention relates to an optical device such as a camera that has a line of sight detection device and can input information based on the movement of an observer's eyes.

[Prior Art] Conventionally, methods for optically (detecting) the line of sight of a subject include 1, a method for determining the position of the 1st and 4th Purkinje images formed by light illuminating the eyeballs (reference document); : J
internal of 0ptical 5ociety
of^merica, vol, 63. NO,8,pa
ge921 (1973)) 2, a method of detecting and determining the position of the first Purkinje image and the center of the pupil (reference document: Japanese Patent Application Laid-Open No. 172552/1983). In addition, a third method has been proposed in which the position of the iris limbus is detected and determined.

However, the first line of sight detection method has problems such as the relative intensity of the fourth Purkinje image with respect to the first Purkinje image is small, and the second line of sight detection method has problems such as difficulty in determining the center of the pupil due to the small reflectance of the iris. Considering practicality, line of sight detection method 3 is effective.

This 3゛ line of sight detection method is carried out using an optical device with an observation section.
For example, when applied to a camera to detect the line of sight of an observer looking into the camera's viewfinder and input the intention of the observer, one method is to place a line of sight detection device near the eyepiece of the camera. .

However, if a line-of-sight detection device is constructed based on the above optical arrangement, the effective light flux area of the eyepiece lens equipped with a mirror that guides the detection light will be larger than the effective light flux area required by the finder optical system. It has been discovered that it becomes difficult for the observer to fix the eyepoint, the range of movement of the eyepoint also increases, the viewfinder field of view becomes more likely to be eclipsed for the observer, and the line of sight detection device becomes difficult to detect the line of sight.

[Problems to be Solved by the Invention] The present invention attempts to maintain a small movement range of the observer's eye point in an optical device such as a camera that detects the line of sight of an observer looking through an eyepiece. It is.

Therefore, the problem is solved by limiting the effective light flux area of the finder optical system in relation to the eyepiece lens.

1 to 3 show a first embodiment of the present invention,
FIG. 1 is a sectional view of a single-lens reflex camera, FIG. 2 is a perspective view of a line-of-sight detection optical system, and FIG. 3 is a diagram explaining the principle of line-of-sight detection.

First, to explain from the eye reflex camera side, 101
is a photographic lens that is fixed to the camera body or can be attached or detached, 1
02 is a quick return mirror whose central portion is formed into a semi-transparent mirror; 103 is a focusing plate; 104 is a display element that displays various photographic information simultaneously or selectively; for example, a liquid crystal display; 105 is a condenser lens; 106 is a pentaprism.

In addition, 107 is a submirror, and 1o8 is a focus detection unit that can detect multiple positions of the line of sight, but these parts are not directly related to the purpose of this application and are well known to those skilled in the art, so their explanation will be omitted. .

Reference numeral 109 denotes a control circuit for signal processing, display panel driving, and focus adjustment, into which detection information on the line of sight direction, detection information on each detection position, and photometry information from a plurality of positions from an exposure photometry unit (not shown) are manually input. Note that the information from each unit can be manually input in various forms, such as undetected raw data, information on the results of arithmetic processing, and even selected information.

On the other hand, the reference numeral 1 constituting the detection system indicates an image sensor of a solid-state imaging device, 2 indicates an imaging lens, and 3 indicates the position of an eye point of a finder. It is assumed that the imaging lens 2 is focused near the eye point 3. 4.4 in FIG. 2 is a light source for illuminating the anterior segment of the eye, and in this example an infrared light emitting diode is used.

Reference numeral 5 denotes an eyepiece lens, which has a built-in beam splitter 5' like a dichroic mirror for infrared reflection, and has a finder and a detection system coaxially connected to it. Reference numeral 6 denotes a finder effective light flux limiting block, the detailed structure of which will be described later. 7 is a signal processing circuit.

Here, before explaining the operation of the above configuration, the detection method will be explained in the third section.
Explain using diagrams.

As shown in the figure, the rotation angle of the eyeball is θ, and the eyepiece 2
Let S be the shift amount of the eyeball with respect to the optical axis of :=distance: Y" 2, so from this, -2 becomes as shown in the following equation.

... (1) However, a=c-Fy7F.

However, b is the radius of the iris, C is the radius of curvature of the anterior surface of the cornea, °C is the distance from the imaging lens 2 to the anterior surface of the cornea, and γ is the distance from the center of rotation of the eyeball to the anterior surface of the cornea.

Now, there are no differences among practical people in these quantities. In other words,
If c, fl, γ, and a are considered constants, equation (1) becomes θ, S
This is a simultaneous equation for θ, so if you solve this, you will get θ.

S can be found.

The solution is ((y-a) sin θ-b cos θ) (2) Therefore, if the coordinates of the left and right ends of the iris limbus are determined using the image sensor 1, the rotation amount θ and shift amount sh of the eyeball E can be accurately determined.
<It is determined by calculation. In addition, the optical axis and visual axis of the eyeball 3 (
Since the line of sight (line of sight) varies in a well-known manner, the direction of the line of sight is actually determined by electrically correcting the amount of rotation of the eyeball 3.

The effects of the embodiment will be explained below.

As shown in FIG. 1, the line of sight detection optical system includes an imaging lens 2, an image sensor 1, and an infrared light emitting diode 4 (not shown) for illuminating the eyeball, and is arranged above an eyepiece 5. FIG. 2 shows a perspective view of the line of sight detection optical system. The infrared light emitting diode 4 is arranged on the side of the imaging lens 2 (±y direction in the figure), and the emitted infrared light is reflected by the dichroic mirror of the eyepiece 5 to diffusely illuminate the eyeball 3.

Here, the infrared light is projected obliquely from a position off the optical axis of the line-of-sight detection optical system, so the upper surface A of the dichroic mirror part of the eyepiece 5 is wider than the area necessary to pass the finder effective light beam. Become. As a result, the exit surface B of a portion of the dichroic mirror also becomes wider, and the range of movement of the eye point of the observer observing the finder also becomes wider. In order to make the range of movement of the observer's eye point similar to that of the prior art, in this embodiment, a limiting block 6 is provided on the finder light flux incident surface of the eyepiece 5 to block light outside the finder effective light flux. As a result, the finder light flux observable to the observer is set to be the same as in the conventional case, and the moving range of the observer's eye point is also maintained in the same manner as in the conventional case.

The infrared light scattered and reflected by the iris limbus of the eyeball enters the eyepiece lens 5 again, is reflected by the dichroic mirror 5, and forms an image on the image sensor 1 via the imaging lens 2. From the coordinates of the iris limbus, the line-of-sight detection signal processing circuit 7 calculates the line-of-sight direction and further the viewpoint within the viewfinder visual field of the observer, and the gaze point information is sent to the control circuit 109 and the multi-point focus detection unit 108 via it. transmitted. The display element 103 is, for example, a guest-host type 71 that does not use a polarizing plate.
! Based on the signal from the display element driving circuit 109, the crystal element displays the gaze point information in a superimposed manner (FIG. 4P) within the viewfinder field of view. Note that a part of the object light that has passed through the photographic lens lO1 passes through the quick return mirror 102, is reflected by the submirror 107, and is guided to a multipoint focus detection unit 1108k. The multi-point focus detection unit 108 detects the focus of the object to be gazed on based on the gaze point information from the signal processing circuit 7, and adjusts the focus of the photographic lens 101 using a photographic lens driving device (not shown).

In this embodiment, an example is shown in which the line of sight detection device is used as a gaze point information input means of the multi-point focus detection unit 108, but it can also be used as a photometry point input means of a multi-point photometry device for exposure, a shooting mode selection means, etc. You may use it. The shooting mode is selected, for example, by displaying various shooting mode marks side by side in a part of the viewfinder field of view, detecting the line of sight of the observer who is fixating on one of them, and then instructing the camera control unit to select the shooting mode. The shooting mode is set.

[Other Embodiments] FIGS. 4 and 5 are diagrams for explaining a second embodiment of the present invention, and FIG. 5 is a perspective view of the line of sight detection optical system.

In the figure, 6' is a dielectric multilayer film area which is a finder effective light flux limiting mask, and FIG. 6 is a spectral transmittance characteristic diagram of the dielectric multilayer film. The other members are the same as those in the first embodiment.

Similar to the above, the line of sight detection optical system is composed of an imaging lens 2, an image sensor 1, and an infrared light emitting diode 4.4 for illuminating the eyeball, and is arranged above the eyepiece 5 of the single-lens reflex camera. The infrared light emitting diode 4.4 is placed on the side of the imaging lens 2 (±y direction in the figure), and the emitted infrared light is
The light is reflected by the dichroic mirror of the eyepiece 5 to illuminate the eyeball. In this embodiment, a dielectric multilayer film region 6 is provided on the finder light beam output surface (plane B in the figure) of the eyepiece lens 5 to shield the outside of the finder effective light beam. The spectral transmittance characteristics of the dielectric multilayer film region 6 are as shown in FIG.
It has the property of blocking almost all visible light but allowing infrared light to pass through. As a result, the viewfinder visual field observable to the observer is set in the same way as before, and the moving range of the observer's eye point is also maintained the same as before. The infrared light diffusely reflected at the iris limbus of the eyeball enters the eyepiece lens 5 again, is reflected by a portion of the dichroic mirror, and is imaged on the image sensor 1 via the imaging lens 2. It is similar in that the direction of the line of sight and further the viewpoint within the viewfinder field of view of the observer is calculated by a line of sight detection circuit (not shown) from the coordinates of the iris limbus.

It should be noted that the present invention can be applied not only to cameras but also to various observation devices such as monitoring devices and microscopes.

[Effects of the Invention] As explained above, in an optical instrument having a device for detecting the line of sight of an observer through an eyepiece, by providing a means for defining an effective light flux area of a finder optical system in the eyepiece, observation is possible. This has the effect of keeping the movement range of the user's eye point small. As a result, the observer's eye point does not move significantly and the funder field of view is not vignetted, and the visual line detection device also has the effect that the visual line detection accuracy is improved by the small movement of the eye point.

[Brief explanation of drawings]

FIG. 1 is an optical sectional view showing an embodiment of the present invention. FIG. 2 is a perspective view showing the main parts of the embodiment. FIG. 3 is a diagram for explaining the detection method. FIG. 4 is a diagram showing an example of the viewfinder field of view. Fifth
The figure is a perspective view showing main parts of another embodiment. Figure 6 is a transmittance characteristic diagram.

Claims (2)

[Claims] (1) For limited use, which has a device that detects the observer's line of sight through the eyepiece, limits the effective light flux area of the finder that comes from the object and passes through the eyepiece, and does not limit the light for line of sight detection. An optical device having a line of sight detection device, characterized in that it is provided with a means for detecting a line of sight. (2) The limiting means is a visible light blocker disposed at or adjacent to a part of the eyepiece, which has a beam splitter and an eyepiece that integrate the finder system and the line of sight detection device. An optical device comprising the line of sight detection device according to item 1.