KR100326539B1 - Lighting apparatus - Google Patents

Abstract

PURPOSE: A lighting apparatus is provided to improve the adjustment of an illumination angle by employing a structure using a few light source. CONSTITUTION: An observing optical system is provided for observing a subject. A light reflector(30) comprises a light reflecting surface for reflecting a light from a light source(32) to the subject to be observed. The light reflecting surface is comprised of a concave surface which is formed by rotating a part of a parabola having a focus F around a rotational shaft(33) perpendicular to a corresponding parabolic axis. The light outputted from the light source(32) is incident to the light reflecting surface in a direction perpendicular to the rotational shaft(33). A light axis of the observing optical system corresponds to an axis of the rotational shaft(33). A moving unit moves the light source(32) along the rotational shaft(33).

Description

Lighting device

The present invention relates to a lighting device, and more particularly, to a lighting device for illuminating an object to be observed, and always relates to a lighting device that continuously changes the illumination angle without steps while illuminating the observation center with sufficient illumination.

In an assembly / inspection apparatus such as an electronic component or an electronic circuit, an illumination device is used to project an image of an object onto a screen, or to image an imaging device such as a CCD camera.

The illumination device is required to vary the illumination conditions such as the light irradiation angle according to the surface state of the object or the purpose of inspection or the like, for example, when the surface of the object is close to the glass surface, generally a projection lens or an imaging device on a screen The light must be illuminated at an angle that prevents specular light from entering the light. On the contrary, when observing a light diffusing surface, the light must be illuminated at an angle close to the specular reflection condition in order to secure the image brightness.

In addition, when the image obtained by imaging the surface of an object is image-processed by a CCD camera to grasp the position and length of a specific portion, when the shadow occurs according to the concave convexity of the surface of the object, shading occurs because it causes measurement error. It should be illuminated so as not to.

Conversely, in order to detect the feature of the object, illumination may be required to emphasize the shadow depending on the concave convexity of the surface.

Conventional lighting devices are arranged to improve direct light sources, such as LEDs, to the irradiation surface, and to cope with the above-described request to change the illumination state, as shown in FIG. It consists of a configuration placed on.

For example, when the outside light source group 21 is used, the observation object 25 can be illuminated in an oblique direction, and when the inside light source group 23 is used, the object 25 is illuminated at an angle close to the vertical direction. can do.

The object 25 to be illuminated is picked up by the CCD camera 27 or the like in the vertical direction and observed or inspected.

In the conventional lighting apparatus, since a plurality of light sources must be arranged with different irradiation directions, that is, angles, adjustment of positions and directions of each light source is cumbersome. Since the number of light sources increases in proportion to the number of illumination directions, increasing the number of illumination directions increases the problem of the adjustment of the light sources more and more.

In addition, since the illumination direction can be selected only at the center of the discrete angle prepared in advance, there is a disadvantage in that it is not always possible to satisfy the illumination condition that is optimal for the surface state of the object to be observed or for the purpose of observation.

Therefore, an object of the present invention is to solve the above disadvantages, and to provide a lighting device that can continuously change the irradiation angle with a simple structure using a few light sources.

<Means for solving the problem>

Referring to the accompanying drawings, the most preferred embodiment which can easily practice this invention by the said structure is as follows.

In the embodiment of the present invention, as the reflector, a concave curved surface formed by rotating a part of the parabola around an axis perpendicular to the parabolic axis is used, and the irradiation angle is continuously changed by changing the light incidence position to the reflector by a light source moving mechanism or the like. Can be changed.

In addition, in the embodiment of the present invention, the irradiation angle can be continuously changed by using a conical surface or a polygonal surface as a reflector, combining the reflector with a Fresnel lens, and changing the light incidence position to the reflector by a light source moving mechanism or the like. have.

This invention is made based on such content.

The light source is disposed radially around a concave curved surface formed by rotating a portion of the parabola around an axis perpendicular to the parabolic axis, and a reflector propagation axis consisting of a conical surface or a polygonal surface.

Light rays output from the light source are incident on the reflecting surface in a direction perpendicular to the central axis of the reflecting mirror. The light beam output from the light source may be directly incident on the reflector, or may be reflected on a small conical mirror or a polygonal mirror arranged inside the reflector and then incident on the reflector.

The light source, or the compact conical mirror or polygonal mirror described above, is movable along the central axis of the reflecting mirror and continuously changes the illumination angle by changing its position.

As a light source, it is good to use light with strong directivity, such as LED and a mini halogen lamp.

1 is an explanatory diagram of a sub-reflection surface formed by rotating a part of a parabola.

2 is a conceptual diagram of a conventional lighting device.

3 is a schematic cross-sectional view of one embodiment of a lighting device according to the invention.

4 is a view for explaining the principle of changing the illumination angle.

5 is an explanatory diagram of the illuminance distribution of the light irradiation surface.

6 is a schematic cross-sectional view of one embodiment of a lighting device according to the present invention with a modified light source portion.

7 is a view for explaining the principle of changing the illumination angle in the embodiment of FIG.

8 is a schematic view of one embodiment of a lighting device according to the invention.

9 is an explanatory view of the light path of the lighting apparatus of FIG.

10 is a modified view of another embodiment in which the light source portion is changed.

* Description of the symbols for the main parts of the drawings *

10: parabola 12: parabolic axis 15: rotating surface

21.23: Light source group 25.36: Observation object 27: CCD camera

30: light reflector 31: fixed plate 32: light source

33: center axis (rotation axis) 37: imaging device 38: light source fixing plate

40: sub-reflection surface 50: conical surface light reflection body 60: Fresnel lens

70: polygon surface 80: outer cylindrical member 81: slot

83: inner cylindrical member 84: fixing screw

<Action>

Light incidence position to the reflector by a reflection optical system using a concave curved surface formed by rotating a part of the parabola around an axis perpendicular to the parabolic side, or by using a conical or polygonal surface and a Fresnel lens in combination with a light source moving mechanism. By adopting a configuration for changing the shape, it is possible to change the illumination angle continuously without a step with a simple structure.

In addition, according to the properties of the optical system described above, it is possible to always illuminate the observation center at a high angle even if the illumination angle is changed. In addition, since the number of light sources is small, the adjustment of the optical system is very easy.

Example

Hereinafter, the present invention will be described in detail with reference to Examples.

1 shows a concave reflective surface formed by rotating a portion of the parabola around an axis perpendicular to the axis of the parabola.

As shown in FIG. 1A, part 11 of parabolic 10 having focal point F is rotated about an axis 13 perpendicular to parabolic axis 12, as shown in FIG. A rotating surface as shown is obtained.

The peripheral portion 16 of the rotating shaft 13 of the rotating surface 15 is preferably an opening for the observation optical system described later.

In the embodiment of the present invention, the rotating surface 15 is used as the reflecting surface of the illumination optical system.

As the cross section is briefly shown in FIG. 3A, the light reflector 30 having the rotational reflecting surface is fixed to the outer cylindrical member 80 by the crimping member 86, and the outer cylindrical member 80. Is fixed to the upper fixing plate 31.

Therefore, the light reflection body 30 will be in the state suspended on the fixed plate 31, and the clearance gap between the light reflection surface and the light irradiation surface will be formed. The plurality of light sources 32 are disposed radially around the axis of rotation of the light reflector 30, that is, the central axis 33.

The plurality of light sources 32 are fixed on the light source fixing plate 38 and are designed to be movable along the central axis 33 integrally by the light source moving mechanism.

In this example, the focal point F of the parabola which is the root of the reflecting surface is set to coincide with the observation center C, that is, on the central axis 33 and on the light irradiation surface. Observation is made by an imaging device 27 such as a CCD camera arranged on the rotating shaft 33.

The imaging device 37 is fixed to the illumination device by the screw 85, and the height of the imaging device can be adjusted by loosening the screw 85.

Moreover, the imaging device 37 is equipped with the lens which has a suitable focal length so that the light which injects into an imaging lens by the movable part of the light source moving mechanism mentioned later may be taken.

Focusing of the imaging device 37 is made in accordance with lens adjustment.

The projection lens may be disposed on the rotation shaft 33, and the screen may be disposed in the image direction of the light reflection body 30, and the image of the observation object 350 may be projected onto the screen by the projection lens.

The light source fixing plate 38 for fixing the light source 32 is attached to the lower end of the inner cylindrical member 83, as shown in FIG. The inner cylindrical member 83 is movably inserted into the center of the outer cylindrical member 80 fixed by the member 86 pressed against the top of the light reflection body 30.

A slot 81 is formed in the outer cylindrical member 80, and the inner cylindrical bonsai 83 is fixed to the outer cylindrical bonsai 80 by a fixing screw 84 passing through the slot 81.

Loosen the set screw 84, and then move the inner cylindrical portion 83 up and down with the set screw 84 to set the height of the light source 32, and in this state, tighten the set screw 84 to (32) can be set to any height position.

Each light source 32 is arranged such that its optical axis is directed in the horizontal direction and in the radial direction from the optical axis 33, and the light rays 34 generated from the light source 32 are reflected by the light reflector 30 to be observed. The surface of 35 is illuminated at a predetermined angle.

In addition, the light source moving mechanism using the fixing screw shown in FIG. 3 is only an example, and the objective of this invention can be achieved even if it uses any light moving mechanism.

As shown in (a) and (b) of FIG. 4, according to this lighting apparatus, the position of the light source 32 is changed in the vertical direction so that the irradiation angle is continuously in the range of 75 ° to 15 °, for example. Can change.

That is, as the light source 32 moves away from the light irradiation surface, an illumination angle close to vertical is obtained, and as the light source 32 gets closer to the light irradiation surface, an illumination angle close to horizontal is obtained.

Furthermore, light rays incident in parallel to the parabolic axis can always illuminate near the observation center C of the object to be observed, even if the light window position changes, depending on the nature of the parabola reflected from the parabola and then passing through the focal point.

(A) of FIG. 5 shows that the 12 LED light sources are arranged at 30 ° intervals under the condition that the focal point of the focal length having a focal length of 80 mm is positioned on the axis of rotation to form a reflecting surface and the focal point is located on the irradiation surface. In this case, the illuminance distribution on the irradiation surface is calculated.

The number corresponding to each contour represents the relative illuminance.

(B) of FIG. 5 shows the illuminance profile on the line passing through the observation center (C). As can be seen from FIG. 5, illuminance of 20% or more of the highest illuminance is obtained in the range of ± 20 mm at the observation center C, and according to this illuminating device, an object with a diameter of 40 mm can be observed with sufficient illuminance to the periphery.

In this invention, although the focal point of the parabola is set to coincide with the observation center C, that is, on the rotation axis 33 and on the light irradiation surface, the focal position is determined according to the characteristics of the light source used. In some cases, a method in which the information is set apart in the vertical direction or the left and right directions is advantageous in terms of equalizing the illuminance distribution on the irradiation surface.

Instead of irradiating the light emitting surface directly toward the reflecting surface (hereinafter referred to as the main reflecting surface) in which part of the parabola is rotated, the light source output from the light source 32 is reflected to another reflecting surface as shown in FIG. (Hereinafter referred to as a sub-reflection surface) (40) may be reflected once and then incident to the main reflection surface (30).

In the sub-reflection surface 40, a cone mirror or a polygon mirror having an inclined surface equal to the number of light sources may be used. The conical mirror or polygonal mirror is arranged in the inner space of the main reflection surface so as to coincide with the central axis 33 of the main reflection surface.

When the sub-reflection surface 40 is used, the light source 32 can be arrange | positioned so that the long-axis direction may face an up-down direction, and it can have a compact design.

In addition, when the light source 32 and the sub-reflective surface 40 are used, the light source 32 can be arrange | positioned so that the long-axis direction may face to an up-down direction, and a compact design can be carried out.

In addition, by providing a mechanism for moving the light source 32 and the sub-reflection surface 40 integrally in the vertical direction, the illumination angle can be continuously changed as shown in FIGS. 7A and 7B. .

FIG. 7A illustrates a case where the heights of the light source 32 and the sub-reflection surface 40 are set high, and the observation object 35 is illuminated at an angle close to the vertical.

In the case where the light source has an elongated shape, when the arrangement as shown in FIG. 3 in which the optical axis of each light source is directed directly to the light reflection surface is made, the light emitting point of the light source is separated from the rotation axis 33 of the main reflection surface in the upward direction of the light source. Although the range of movement to is limited, it is difficult to obtain an illumination angle close to vertical, but according to the arrangement shown in FIG. 6 using the sub-reflective surface 40, this difficulty is eliminated and even in the case of using an elongated light beam, It is possible to easily obtain a lighting angle close to.

As a mechanism for moving the light source and the sub-reflection surface integrally, any one, for example, the mechanism shown in FIG. 3 can be used.

In addition, the sub-reflection surface 40 is preferably cut out around the central axis to facilitate the arrangement of the observation optical system.

Hereinafter, a second embodiment of a lighting apparatus using a light reflector having a conical surface or a polygonal surface and a Fresnel lens assembly will be described.

(A) of FIG. 8 is an external view of the lighting apparatus using the light reflector 50 having a conical surface having a 90 ° right angle as a reflecting surface.

A fresnel lens 60 is mounted in the downward direction of the conical light reflector 50, and the whole is suspended from the fixing plate mounted in the upward direction as in the above-described embodiment, for example.

It is advantageous to arrange the imaging device 37 such as a CCD camera on the central axis of the conical light reflector 50.

If necessary for the placement of the observation optical system, it is possible to cut the head of the conical light reflector 50 to provide an opening.

As a reflector instead of a conical surface, as shown in (b) of FIG. 8, a polygonal surface 70 having the same number of slopes as the number of light sources (eight shown) and having an angle of 45 ° with each slope as a central axis. The same lighting apparatus can be configured also by using.

Hereinafter, the case where a cone surface is used for the light reflection body 50 is demonstrated.

As in the case of the first embodiment, a plurality of light sources are arranged radially around the central axis of the conical surface which becomes the light reflector. It is preferable to set the light irradiation surface which arrange | positions the observation object 35 to the downward direction of the Fresnel lens 60, and around the focal length of the Fresnel lens 60.

As briefly shown in the cross-sectional view of FIG. 9, the light rays generated mostly in the horizontal direction from the light source 32 are reflected by the reflector 50, and the direction is changed mostly in the vertical direction, which is then refracted by the Fresnel lens 60. The observation object 35 on the light irradiation surface is illuminated at a predetermined angle.

When the position of the light source 32 is moved up and down according to the light source moving mechanism having an arbitrary structure, the light passing position in the Fresnel lens 60 is changed, and accordingly the illumination angle of the observation object 35 is also changed.

Since the light irradiation surface is set close to the focal length of the Fresnel lens 60, it is possible to always illuminate the periphery of the observation center C with high illumination even if the illumination angle changes.

The light source 32 instead of directly irradiating the light emitting surface toward the conical reflecting surface (hereinafter referred to as the main reflecting surface) 50, as shown briefly in FIG. 10, the light beam output from the light source 32 May be reflected once on another reflective surface (hereinafter referred to as a sub-reflective surface) 40 and then incident on the main reflective surface 50.

As the reflecting surface 40, the conical mirror or the polygon mirror 40 can be arranged in the inner space of the main reflecting surface so that its center axis coincides with the center axis of the main reflecting surface.

When the sub-reflection surface 40 is used, the light source 32 can be arrange | positioned so that the long-axis direction may face an up-down direction, and a compact design can also be carried out.

Further, by designing the mechanism so that the light source 33 and the sub-reflection surface 40 are integrally moved in the vertical direction, the same illumination angle as in the above embodiment can be continuously changed.

If the illumination optical system using the sub-reflective surface 40 is adopted in the case where the light ray has a thin and long shape, it is possible to arrange the axial direction of the light source in the vertical direction, thus limiting the movement of the light source in the internal space of the main reflective surface. It is possible to relax and obtain an illumination angle close to vertical.

Arbitrary things can be selected and used as a mechanism which moves together a light source and a sub-reflection surface. In addition, the sub-reflection surface 40 is preferably cut out around the central axis to facilitate the arrangement of the observation optical system.

As described above, according to the embodiment of the present invention, the illumination angle can be continuously changed without step while always illuminating the observation center with sufficient illumination.

In addition, since the number of light sources is small, it is possible to provide an illumination optical system having an effect of easily adjusting the device.

Claims (7)

In the lighting device for illuminating the object to be observed, A light source; An observation optical system for observing the observation object; And a light reflecting surface for reflecting light from the light source to the object to be observed, wherein the light reflecting surface comprises a concave curved surface formed by rotating a part of a parabola having a focal point F about a rotation axis perpendicular to the parabolic axis. ; And Means for moving the light source, The light output from the light source is incident on the light reflection surface in a direction orthogonal to the rotation axis, the optical axis of the observation optical system coincides with the rotation axis, and the means for moving the light source moves the light source along the rotation axis. Lighting device to be specified. The method of claim 1, And a sub-reflector disposed in an inner space of the light reflector and reflecting light output from the light source to a light reflection surface of the light reflector. The method of claim 2, The sub-reflector is a conical shape of the central axis coincides with the rotation axis, characterized in that movable along the rotation axis. In the lighting device for illuminating the object to be observed, A light source; A light reflector comprising a light reflecting surface for reflecting light from the light source to the observation object; A Fresnel lens disposed between the light reflector and the object to be observed perpendicular to a central axis of the light reflector surface, The light output from the light source is incident on the light reflection surface in a direction orthogonal to the central axis of the light reflection body, and is irradiated to the observation object disposed at the focal length of the Fresnel lens through the Fresnel lens. Lighting device. The method of claim 4, wherein And means for moving the light source along a central axis of the light reflector. The method of claim 4, wherein And a sub-reflector whose central axis coincides with the central axis of the light reflection body, and which reflects the light output from the light source to the light reflection surface of the light reflection body. The method of claim 6, The sub-reflective body is made of a conical or polygonal cone, characterized in that movable along the central axis of the light reflection surface.