JP2593870Y2 - Lighting equipment - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating device which emits auxiliary light for measuring a distance to a subject or detecting a focus.

[0002]

2. Description of the Related Art Various automatic focus detection devices are used in cameras, video cameras and the like. In general, in a passive type automatic focusing (AF) mechanism, focusing can be performed by projecting auxiliary light of a predetermined pattern (for example, vertical stripes) to a subject by an illumination device in consideration of a case of low luminance or low contrast. A method of creating an accurate environment and improving the accuracy of AF is used.

[0003] As a conventional illuminating device, a pattern mask in which a predetermined pattern (for example, a vertical stripe pattern) is formed on a film is generally provided between a light source and a light projecting lens. In the case of such an illuminating device, in order to form an image of the pattern of the pattern mask at a predetermined distance, it is necessary to precisely arrange the light projecting lens and the pattern mask at predetermined positions.

However, in the case of such a lighting device,
At the time of assembling, since the light projecting lens and the pattern mask are separately installed, the distance between the light projecting lens and the pattern mask is not constant due to an assembly error, etc.
As a result, there is a problem that the image formation position of the pattern varies between products. Further, since the light projecting lens and the pattern mask are manufactured as separate components, the number of components is large and the manufacturing cost is high.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lighting apparatus which has a simple structure, has a small number of parts, and has a high precision of a pattern image forming position.

[0006]

This and other objects are achieved by the present invention described in (1) to (6) below.

(1) An illuminating device having a light source and a light projecting lens for projecting auxiliary light for detecting a distance to a subject or a focus to the subject to the subject. The light source side surface is a flat surface, the light source side focal point of the light projecting lens is located near the light source side surface of the light projecting lens, and the light projecting lens is The surface has a concave and / or convex pattern, and a light portion and a dark portion corresponding to the concave and / or convex pattern are formed on the subject. Lighting equipment.

(2) The concave and / or convex pattern includes a surface that is not substantially parallel to and not perpendicular to the light source side surface of the light projecting lens.
The lighting device according to claim 1.

(3) The lighting device according to the above (1) or (2), wherein the concave and / or convex patterns are formed in stripes.

(4) The lighting device according to any one of (1) to (3), wherein the concave and / or convex patterns are formed irregularly.

(5) The light source side surface of the projection lens is
The lighting device according to any one of (1) to (4), wherein the lighting device is inclined with respect to a plane whose normal line is the optical axis of the light projecting lens.

(6) The lighting device according to any one of (1) to (5), further including a light amount adjusting means for adjusting the light amount of the auxiliary light.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a lighting device according to the present invention. The use of the lighting device of the present invention is not particularly limited.
The case where the lighting device of the present invention is applied to a camera will be described.

FIG. 1 is a side view showing an example of the configuration of the lighting device of the present invention. The illustrated illumination device 1 of the present embodiment projects a passive type auxiliary light for automatic focus detection onto a subject (subject), or detects a distance (distance measurement) to the subject. The present invention is applied to a device that projects auxiliary light to a subject, and includes a light projecting lens 2, a light source 3, and an aperture 4. As the light source 3, for example, a light emitting diode can be used.

The light projecting lens 2 is a plano-convex lens having an incident surface 2A, which will be described later, as a plane, and is installed in front of the light source 3 (light projecting side). The light projecting lens 2 has a concave and / or convex pattern (hereinafter, referred to as an uneven pattern) on a surface 2A on the light source 3 side (hereinafter, referred to as an incident surface). In addition, this uneven pattern will be described later in detail.

The projection / recess pattern of the light projecting lens 2 is formed at a predetermined distance (on the subject) by adjusting various conditions such as the refractive index, shape, and dimensions (for example, lens thickness, lens diameter, lens curvature). It is set to image.

In this case, the light projecting lens 2 in this embodiment is
Is a flat surface, a surface 2B opposite to the light source 3 (hereinafter referred to as an emission surface) 2B is a convex curved surface, and a focal point F of the light projecting lens 2 on the light source 3 side is It is located near and inside the light projecting lens 2. The focal point F is
It may be located on or near the incident surface 2A and outside the light projecting lens 2.

As described above, in the illumination device of the present invention, since the projection / recess pattern is formed on the projection lens 2, the optical position of the projection / recess pattern with respect to the projection lens 2 (the projection lens 2)
The distance between the entrance surface 2A and the exit surface 2B) is fixed.
As a result, as compared with a conventional illuminating device in which the light projecting lens and the pattern mask are separately installed, the focus accuracy of the concavo-convex pattern is improved, and the image-forming position of the concavo-convex pattern between products is made uniform.

An aperture 4 is a light amount adjusting means for adjusting the amount of auxiliary light applied to the subject, and is provided on the light exit surface 2B side of the light projecting lens 2. The configuration of the aperture 4 is not particularly limited, and includes, for example, an aperture blade and a unit (for example, an iris motor) for driving the aperture blade. It should be noted that the present invention also includes one in which the aperture 4 is omitted.

Next, a description will be given of an uneven pattern of the light projecting lens 2 in this embodiment. FIG. 2 is a rear view showing a configuration example of the light projecting lens 2, that is, a diagram showing the light projecting lens 2 from the light source 3 side in FIG. FIG.
FIG. 3 is a sectional view taken along line AA in FIG. 2.

As shown in FIGS. 2 and 3, the projection / recess pattern of the light projecting lens 2 in the present embodiment is formed by forming five grooves 21 each having a triangular cross section in a stripe shape. That is, in the present embodiment, by forming such a striped uneven pattern on the incident surface 2A, the incident surface 2A and a surface that is not substantially parallel and not perpendicular to the incident surface 2A (hereinafter referred to as a pattern). 2C) are arranged alternately.

Here, in this embodiment, the shape, size and pitch of the grooves 21 are irregularly formed, so that during the auxiliary light projection, irregularities are formed on the subject as described later. Light projection pattern, that is, the width of the light part 51 and the dark part 53
Are formed in different light emitting patterns.

In the case of such an irregular light emitting pattern, the phase difference of the light emitting pattern during passive automatic focus detection or distance measurement to the object is compared with the regular light emitting pattern. Is less likely to be read erroneously, and erroneous operation of the automatic focus detection mechanism and the like can be prevented.

The irregular pattern of the light projecting lens 2 in the present invention is a regular irregular pattern, that is,
An uneven pattern such that a regular light projection pattern (a light projection pattern in which the width of the light part 51 and the width of the dark part 53 are substantially the same) on the subject is also included.

FIG. 6 shows a case where the projection / recess pattern of the light projecting lens 2 is formed by grooves or projections of various cross-sectional shapes, and the projection / recess pattern of the light projecting lens 2 and the auxiliary light projected from the illumination device 1. It is a figure which shows the correspondence with the projection pattern on an object typically.

When no projection / recess pattern is formed on the light projecting lens 2, auxiliary light having no pattern is projected on the subject. However, as shown in FIG. Is formed on the object, a bright portion 51 having relatively high luminance corresponding to the incident surface 2A and a dark portion 5 having relatively low luminance corresponding to the groove 21a are formed on the subject.
3 are formed. The operation in this case is as follows.

The light incident on the groove 21a of the light projecting lens 2 from the light source 3 is irradiated in a direction different from the light incident on the adjacent incident surface 2A. That is, as shown in FIG. 6, the light irradiated to the groove 21a is refracted on the pattern surface 2C inclined with respect to the incident surface 2A, and therefore travels in a different direction from the light incident on the incident surface 2A, The light is not irradiated upward, and a difference in luminance from the surroundings occurs, thereby forming a dark portion 53.

FIG. 4 is a front view showing a light projection pattern on an object by the auxiliary light emitted from the illumination device 1 of the present embodiment. According to the illuminating device 1 having such a configuration, at the time of auxiliary light projection, as shown in FIG. 4, a band-shaped bright portion (bright line) having a relatively high luminance corresponding to the concavo-convex pattern is formed on the subject.
51 and band-shaped dark portions 53 having relatively low luminance are alternately formed. Such a vertical stripe light projection pattern is projected such that its longitudinal direction is substantially orthogonal to the arrangement direction of a light receiving element array (not shown) for automatic focus detection.

Next, another example of the configuration of the concavo-convex pattern of the light projecting lens 2 in this embodiment will be described. FIG. 5 is a cross-sectional view showing another configuration example of the light projecting lens 2. The concave and convex pattern of the light projecting lens 2 shown in FIG. 5 is formed in stripes by ridges (continuous ridges) 25 each having a triangular cross section. That is, by forming such a striped uneven pattern on the incident surface 2A, the incident surface 2A is formed.
And a light projecting lens 2 in which pattern surfaces 2C are alternately arranged.
Is configured.

In the case of such a concavo-convex pattern formed by the ridges 25, as in the case of the concavo-convex pattern formed by the grooves 21, a vertical-striped light-projection pattern is formed on the subject during auxiliary light projection. You. That is, as shown in FIG. 6, when the projection lens 25a having a triangular cross-sectional shape is formed on the light projecting lens 2, the bright portion 51 corresponding to the incident surface 2A and the projection 25a are formed on the subject. Is formed.

In the present invention, the projection / recess pattern of the light projecting lens 2 may be, for example, a groove (recess) shorter than the above-mentioned groove or a projection shorter than the above-mentioned ridge. These may be arranged intermittently, for example. Further, in the present invention, the concave and convex pattern of the light projecting lens 2 may be formed by only one type of the groove, the ridge, the concave portion and the convex portion, or may be formed by using two or more types in combination. Is also good.

Here, the cross-sectional shapes of the groove 21 and the ridge 25 of the present embodiment are each triangular, but are not limited thereto, and may be any shape. For example, the cross-sectional shapes of the groove and the ridge include, for example, a semicircle, a semi-ellipse, and a trapezoid in addition to the triangle.

As shown in FIG. 6, the groove 21b has a trapezoidal cross section.
In the case where the cross section is a trapezoidal ridge 25b, a bright portion 51 is formed on the subject corresponding to the incident surface 2A and the central surface 2D parallel to the incident surface 2A, respectively, and both sides of the surface 2D are formed. On the subject corresponding to the pattern surface 2C, a dark portion 5
3 is formed.

When the groove 21c has a semicircular cross section and the ridge 25c has a semicircular cross section, the incident surface 2A
And a bright portion 5 on the subject corresponding to the surface 2E at the center.
1 is formed, and a dark portion 53 is formed on the subject corresponding to the pattern surface 2C on both sides of the surface 2E. in this case,
The boundary between the light portion 51 and the dark portion 53 corresponding to the groove and the ridge is clearer in the trapezoidal uneven pattern than in the semicircular uneven pattern. In addition, in the present invention, various conditions such as the number, size, pitch, and the like of the concavo-convex patterns (for example, grooves, ridges, etc.) of the light projecting lens 2 are not particularly limited.

Next, a method for forming an irregular light projection pattern on a subject, that is, a method for forming an irregular pattern on the incident surface 2A of the light projection lens 2 will be described. Methods for forming an irregular light projection pattern on a subject include the following methods.

The size of each groove or ridge of the concavo-convex pattern, for example, the width of each groove or ridge of the concavo-convex pattern is changed. The pitch of each groove or ridge of the concavo-convex pattern is changed. The cross-sectional shape of each groove or ridge of the uneven pattern is changed. For example, a concavo-convex pattern is formed by mixing shapes such as a triangle, a semicircle, a semiellipse, and a trapezoid. In the case where the same concavo-convex pattern is formed, for example, when the cross-sectional shape is a trapezoidal groove and the same-shaped groove is formed, the inclinations of the opposing pattern surfaces are different from each other. In the present invention, only one of the above-mentioned methods may be used, or two or more methods may be used in combination.

Next, another configuration example of the lighting device of the present invention will be described. FIG. 7 is a side view showing a configuration example of the lighting device of the present invention. Illumination device 10 of the present embodiment illustrated
Is a device for projecting auxiliary light for passive automatic focus detection or distance measurement to a subject similarly to the above-described illumination device 1 shown in FIG. Have. The light projecting lens 20 has a predetermined uneven pattern on the incident surface 20A, the incident surface 20A is a flat surface, and the emission surface 20B is a convex curved surface. Hereinafter, main differences from the lighting device 1 illustrated in FIG. 1 will be described.

In this embodiment, the incident surface 2 of the light projecting lens 20
0A is formed to be inclined at a predetermined angle with respect to the surface 7 having the optical axis 63 of the light projecting lens 20 as a normal line. In this case, the contour of the incident surface 20A is an elliptical shape, and the concavo-convex pattern (for example, groove or ridge) is formed in the major axis direction (the direction of arrow B in FIG. 7) of the incident surface 20A.

The light projecting lens 20 has an automatic focus detecting function such that the optical axis 63 of the light projecting lens 20 and the optical axis 61 of the automatic focus detecting optical system intersect practically on the exit surface 20B side. It is installed at an angle to the optical axis 61 of the optical system for use.

In this case, the concavo-convex pattern of the light projecting lens 20 forms an image on or near the optical axis 61 of the optical system for automatic focus detection, that is, the image forming surface of the concavo-convex pattern of the light projecting lens 20 is The lens thickness of the light projecting lens 20 is set so as to be positioned on or near the optical axis 61 of the automatic focus detection optical system in a state parallel or nearly parallel to the optical axis 61.
Various conditions such as the curvature, the angle of inclination of the incident surface 20A, the position of the light projecting lens 20, the angle of inclination of the light projecting lens 20, and the like are set.

Here, the optical axis 61 of the automatic focus detecting optical system coincides with the photographing optical system such as a single-lens reflex camera, and is independent of the photographing optical system such as a compact camera. Some are provided.

In the illumination device 10 having such a configuration, for example, the pattern at the point a is imaged at the point c, and the pattern at the point b is imaged at the point d. Since a certain pattern forms an image between the points c and d, for a subject at a predetermined distance from the camera (for example, a subject at any position between the points c and d), It is possible to form an image of a part of the uneven pattern of the light projecting lens 20 on the subject. As a result, in this embodiment, even if the distance from the camera to the subject changes, a light projection pattern with high contrast and a clear boundary between a bright portion and a dark portion can be obtained.

In this embodiment, the light projecting lens 20 is
Although the optical axis 63 of the light projecting lens 20 and the optical axis 61 of the automatic focus detection optical system are set to be inclined with respect to the optical axis 61 so as to intersect practically on the exit surface 20B side. The invention is not limited to this. For example, as shown in FIG. 8, the light projecting lens 20 is installed such that the optical axis 63 of the light projecting lens 20 and the optical axis 61 of the optical system for automatic focus detection are parallel. May be done.

In this case, the incident surface 20A of the light projecting lens 20
The concavo-convex pattern formed on the upper half (on the upper side of the optical axis 63 in FIG. 8) forms an image on or near the optical axis 61 of the automatic focus detection optical system.
A structure having a concavo-convex pattern only in the upper half of the incident surface 20A may be used.

Here, the light projecting lenses 2, 20 of the illuminating devices 1 and 10 of the present embodiment shown in FIGS.
Is a plano-convex lens whose entrance surfaces 2A and 20A are plane surfaces and the exit surfaces 2B and 20B are convex curved surfaces, respectively. The light-projecting lens in the present invention is a plano-convex lens whose exit surface is a convex curved surface. It is not limited to.

The constituent materials of the light projecting lenses 2 and 20 of the illuminating devices 1 and 10 of the present embodiment are not particularly limited, and various glass materials or plastic materials can be used. In order to integrally form the lens and the lens, it is preferable to use a plastic material that can be molded. The light projecting lenses 2 and 20 made of glass material
In this case, the concave / convex pattern can be formed by, for example, shaving or etching. Further, the physical characteristics (for example, Knoop hardness) and the optical characteristics (for example, transmittance and refractive index) of the light projecting lenses 2 and 20 of the illumination devices 1 and 10 of the present embodiment are not particularly limited. .

The uneven patterns of the light projecting lenses 2 and 20 of the illuminating devices 1 and 10 of this embodiment are usually formed integrally with the light projecting lenses 2 and 20 (integral molding), so that the manufacturing is easy. In addition, the number of parts is reduced as compared with the related art, whereby the configuration can be simplified and the cost can be reduced.

The illuminating device of the present invention is, for example, a single-lens reflex camera, a compact camera, a video camera, a still video camera, or the like, as an illuminating device for projecting auxiliary light for passive automatic focus detection. As an illumination device for projecting auxiliary light for distance measurement to a subject, for example, it is applied to a distance measurement device using a passive automatic focus detection method.

[0049]

As described above, according to the illuminating device of the present invention, since the light projecting lens and the concavo-convex pattern are one component, the light projecting lens and the pattern mask are separately manufactured and installed separately. As compared with the above-described illumination device, the focus accuracy of the concavo-convex pattern is improved, and the imaging position of the concavo-convex pattern between products is made uniform.

Further, the structure can be simplified by reducing the number of parts. In addition, since the number of parts is reduced and the projection / recess pattern is formed only by molding the light projecting lens, the manufacturing cost can be reduced.

Further, according to the illumination device of the present invention in which the incident surface of the light projecting lens is formed to be inclined with respect to the surface whose normal line is the optical axis of the light projecting lens, regardless of the distance to the subject, A light projection pattern having a high contrast and a sharp boundary between a bright portion and a dark portion can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view showing a configuration example of a lighting device of the present invention.

FIG. 2 is a rear view showing a configuration example of the light projecting lens 2 in the present invention.

FIG. 3 is a sectional view taken along line AA in FIG. 2;

FIG. 4 is a front view showing a light projection pattern on a subject by auxiliary light emitted from the illumination device of the present invention.

FIG. 5 is a sectional view showing a configuration example of the light projecting lens in the present invention.

FIG. 6 is a diagram schematically showing the correspondence between the concavo-convex pattern of the light projecting lens 2 and the light projecting pattern on the subject by the auxiliary light projected from the illumination device in the present invention.

FIG. 7 is a side view showing a configuration example of the lighting device of the present invention.

FIG. 8 is a side view showing a configuration example of the lighting device of the present invention.

[Explanation of symbols]

 1, 10 Illumination device 2, 20 Projection lens 2A, 20A Incident surface 2B, 20B Exit surface 2C Pattern surface 2D, 2E Central surface 21, 21a to 21c Groove 25, 25a to 25c Convex stripe 3, 30 Light source 4, Reference Signs List 40 aperture 51 bright part 53 dark part 61 optical axis of optical system for automatic focus detection 63 optical axis of light projecting lens 7 plane F focal points a to d points

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G02B 7/28 G01C 3/06 G03B 13/36

Claims (6)

(57) [Scope of request for utility model registration] 1. An illumination device having a light source and a light projecting lens, and projecting auxiliary light for detecting a distance to a subject or focus detection to the subject to the subject. The light source side surface is a flat surface, the light source side focal point of the light projecting lens is located near the light source side surface of the light projecting lens, and the light projecting lens is the light source side surface A concave and / or convex pattern, wherein a bright portion and a dark portion corresponding to the concave and / or convex pattern are formed on the subject. Lighting equipment. 2. The illumination device according to claim 1, wherein the concave and / or convex patterns include a surface that is not substantially parallel and not perpendicular to a light source side surface of the light projecting lens. 3. The lighting device according to claim 1, wherein the concave and / or convex patterns are formed in stripes. 4. The lighting device according to claim 1, wherein the concave and / or convex patterns are formed irregularly. 5. The lighting device according to claim 1, wherein a surface of the light projecting lens on a light source side is inclined with respect to a surface having a normal to an optical axis of the light projecting lens. 6. The lighting device according to claim 1, further comprising a light amount adjusting unit for adjusting the light amount of the auxiliary light.