JP2010251168A - Ring-lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ring-lighting system capable of performing uniform illumination. <P>SOLUTION: This ring-lighting system 1 includes a plurality of LEDs 2, arranged in a ring shape around the optical axis A of an objective lens 10 for emitting mutually different three kinds of color light; a prism 3 for compositing each color light; and a reflecting mirror 4 for condensing the light composited by the prism 3 on an intersection P. Among the LEDs 2, LED groups 2R, 2G, 2B which emit identical kind of color light are arranged annularly, at a prescribed interval along the surroundings of the optical axis A in the same plane perpendicular to the optical axis A. The prism 3 and the reflecting mirror 4 are formed annularly along the surroundings of the optical axis A. Accordingly, the reflecting mirror 4 can converge light emitted from the LED group 2R, 2G, 2B and synthesized by the prism 3 so as to radially direct it toward the optical axis A. Thus, the ring-lighting system 1 can perform uniform illumination. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a ring illumination device.

Conventionally, a plurality of light emitting elements that are arranged in a ring shape around the optical axis in an optical system and emit at least two different types of color light, a composite element that combines each color light, and a composite element There is known a ring illumination device including a condensing element that condenses light at a predetermined position along the optical axis (see, for example, Patent Document 1).
The ring illumination device described in Patent Document 1 is a mirror group (combining element) including a plurality of light emitting diodes (light emitting elements) that emit three kinds of colored light (red, green, and blue), a reflecting mirror, and a dichroic mirror ) And a reflecting mirror (light condensing element).

JP 2003-337365 A

  However, in the ring illumination device described in Patent Document 1, each light emitting element is arranged in a rectangular shape along the periphery of the optical axis in the same plane substantially orthogonal to the optical axis in the optical system, and the color light emitted by each light emitting element. The light emitting element is separated from the optical axis and is substantially perpendicular to the arrangement direction of the light emitting elements. It cannot be condensed. This is because the dichroic mirror can only be formed in a straight line. Therefore, the ring illumination device described in Patent Document 1 has a problem that uniform illumination cannot be performed.

  The objective of this invention is providing the ring illuminating device which can perform uniform illumination.

  In the present invention, a plurality of light emitting elements that are arranged in a ring shape around the optical axis in the optical system and that emit at least two different types of color light, a combining element that combines the color lights, and the combining element A light-emitting element group that emits the same type of color light among the light-emitting elements. The light-emitting element group includes a light-collecting element that condenses the combined light at a predetermined position along the optical axis. Are arranged in an annular shape at a predetermined interval along the circumference of the optical axis in the same plane substantially orthogonal to the optical axis, and the combining element and the condensing element are arranged along the circumference of the optical axis. It is characterized by being formed in an annular shape.

  According to such a configuration, each light emitting element group, the combining element, and the light collecting element are formed in an annular shape along the circumference of the optical axis in the optical system. Can be condensed radially toward the optical axis. Therefore, the ring illumination device can perform uniform illumination.

  In the present invention, the emission direction of the colored light from each light emitting element group is set to directions inclined at different angles in the same plane including the optical axis, and the combining element disperses each incident color light. It is preferable that the prisms are combined and emitted in the same direction.

  According to such a configuration, the prism can be easily formed in an annular shape, so that the ring illumination device can perform uniform illumination with a simple configuration.

  In the present invention, each of the light emitting element groups, the combining element, and the light collecting element are formed so as to increase in diameter in order, and are disposed along the same plane substantially orthogonal to the optical axis. It is preferable.

Here, since each color light emitted from each light emitting element group needs to be condensed at a predetermined position avoiding the optical system, it is collected by the light collecting element after being emitted in a direction away from the optical axis. It is desirable to be illuminated.
According to the present invention, each light emitting element group, the combining element, and the light collecting element are sequentially arranged in a direction away from the optical axis, so that each color light emitted from each light emitting element group is After being emitted in a direction away from the optical axis, the light can be condensed by a condensing element.

  In the present invention, the light collecting element collects light at the predetermined position by reflecting the light reflected by the first reflecting mirror and the first reflecting mirror that reflects the light combined by the combining element. Each light emitting element group, the composite element, and the first reflecting mirror are formed to have substantially the same diameter, and are sequentially arranged along the optical axis. The first reflecting mirror preferably reflects the light combined by the combining element in a direction away from the optical axis.

Here, as described above, when each light emitting element group, the combining element, and the light condensing element are sequentially arranged in the direction away from the optical axis, the ring illumination device has a diameter that can simplify the configuration. Get bigger in the direction.
According to the present invention, each light emitting element group, the combining element, and the first reflecting mirror are formed so as to have substantially the same diameter and are arranged in order along the optical axis. An increase in size can be suppressed.
In addition, since the first reflecting mirror reflects the light combined by the combining element in the direction away from the optical axis, each color light emitted from each light emitting element group is emitted in the direction away from the optical axis. Then, it can be condensed by the second reflecting mirror.

  In the present invention, the emission directions of the colored lights by the respective light emitting element groups are set to be substantially the same in the same plane including the optical axis, and the combining element is configured to reflect the incident colored lights internally. It is preferable that the Kester prism emits in the same direction.

  According to such a configuration, since the emission direction of the colored light by each light emitting element group is substantially the same direction in the same plane including the optical axis, as described above, the prism is employed as the synthesis element. Compared to the case, the angle of each light emitting element group can be easily adjusted. Therefore, the manufacturing cost of the ring illumination device can be reduced.

  In the present invention, it is preferable to include a plurality of collimating lenses that are arranged between the light emitting element groups and the combining element and collimate the color lights emitted from the light emitting element groups.

  According to such a configuration, the condensing element can efficiently condense each color light by collimating each color light emitted from each light emitting element group with each collimating lens. Therefore, the illumination efficiency of the ring illumination device can be improved.

The cross-sectional schematic diagram which shows the ring illuminating device which concerns on 1st Embodiment of this invention. The schematic diagram which looked at the ring illuminating device in the said embodiment from the upper side. The figure which shows the state which moved the reflecting mirror and unit in the said embodiment along an optical axis. The cross-sectional schematic diagram which shows the ring illuminating device which concerns on 2nd Embodiment of this invention. The cross-sectional schematic diagram which shows the ring illuminating device which concerns on 3rd Embodiment of this invention. The cross-sectional schematic diagram which shows the ring illuminating device which concerns on 4th Embodiment of this invention.

[First Embodiment]
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing a ring illumination device 1 according to the first embodiment of the present invention. In FIG. 1, only the ring illumination device 1 is cut, and the cutting of the objective lens 10 is omitted. In FIG. 1, the upper direction is defined as the + Z-axis direction, and two axes orthogonal to the Z-axis are described as an X-axis and a Y-axis, respectively. The same applies to the following drawings.

As shown in FIG. 1, the ring illumination device 1 illuminates a workpiece W measured by an image measuring machine or the like (not shown), and is applied to an objective lens 10 as a magnifying optical system such as an image measuring machine. It is attached.
The ring illumination device 1 is arranged as a ring around the optical axis A (Z axis) of the objective lens 10 and emits three different types of light (red, green, blue). LED 2 (Light Emitting Diode), prism 3 as a combining element for combining light of each color, and light combined by prism 3 at a predetermined position along optical axis A, that is, optical axis A and object W to be measured The reflecting mirror 4 as a condensing element which condenses to the intersection P with the surface of this is provided. Each LED 2 and prism 3 are configured as an integrated unit 5, and the image measuring machine or the like can move the reflecting mirror 4 and unit 5 along the optical axis A.

FIG. 2 is a schematic view of the ring illumination device 1 as viewed from above. In FIG. 2, only each LED 2 and the reflecting mirror 4 are shown.
Among the LEDs 2, LED groups 2R, 2G, and 2B that emit the same type of color light (2R that emits red light, 2G that emits green light, 2G that emits blue light, and 2B that emits blue light) 1 and 2 are arranged in an annular shape at predetermined intervals along the periphery of the optical axis A in the same plane (XY plane) substantially orthogonal to the optical axis A, as shown in FIGS. ing. The LED groups 2R, 2G, and 2B are sequentially arranged in the −Z-axis direction from the LED group 2R that emits red light having a long wavelength to the LED group 2B that emits blue light having a short wavelength.
Further, the LED groups 2R, 2G, and 2B are arranged so that the incident angles of the respective color lights to the prism 3 increase in order from the LED group 2R to the LED group 2B. That is, the emission direction of the color light by the LED groups 2R, 2G, and 2B is set to be inclined at different angles in the same plane including the optical axis A.

  The prism 3 combines the incident color lights by dispersing them and emits them in the same direction. The prism 3 is formed in a triangular cross section having an incident end face 3A on which each color light emitted from the LED groups 2R, 2G, and 2B is incident and an exit end face 3B that emits synthesized light, and an optical axis A. It is formed in an annular shape along the periphery of. Then, the prism 3 emits the combined light in the direction away from the optical axis A along the X-axis direction (+ X-axis direction). The prism 3 is formed with a larger diameter than the LED groups 2R, 2G, and 2B, and is arranged along a plane on which the LED groups 2R, 2G, and 2B are arranged.

The reflecting mirror 4 has a reflecting surface 4A that reflects the light synthesized by the prism 3, and is formed in an annular shape along the periphery of the optical axis A. The reflecting mirror 4 is formed with a larger diameter than the prism 3, and is disposed along a plane on which the LED groups 2R, 2G, 2B are arranged. That is, the LED groups 2R, 2G, 2B, the prism 3, and the reflecting mirror 4 are formed so as to increase in diameter in order, and are disposed along the same plane substantially orthogonal to the optical axis A.
The reflection surface 4A has a curved shape in which an end on the + Z-axis direction side protrudes toward the optical axis A side and becomes a surface substantially parallel to the optical axis A toward the −Z-axis direction. The light emitted from the prism 3 and reflected by the reflecting surface 4A is collected at the intersection P.
In FIGS. 1 and 2, the optical path of illumination by the ring illumination device 1 emitted from the LED groups 2R, 2G, and 2B and reaching the intersection P is indicated by a one-dot chain line.

FIG. 3 is a diagram illustrating a state in which the reflecting mirror 4 and the unit 5 are moved along the optical axis A. In FIG. 3, a state before the reflecting mirror 4 and the unit 5 are moved is indicated by a two-dot chain line.
An image measuring machine or the like can change the angle of the light collected at the intersection P by moving the reflecting mirror 4 and the unit 5 along the optical axis A. For example, as shown in FIG. 3, the position of light emitted from the prism 3 can be changed in the −Z axis direction by moving the unit 5 in the −Z axis direction. When the relative position of the reflecting mirror 4 and the unit 5 is changed by moving the reflecting mirror 4 in the −Z-axis direction, the position at which the light emitted from the prism 3 is reflected by the reflecting surface 4A of the reflecting mirror 4 is changed. Can be changed. Here, since the reflecting surface 4A has a curved shape, the light that is collected at the intersection P by changing the position at which the light emitted from the prism 3 is reflected by the reflecting surface 4A of the reflecting mirror 4 is changed. The angle can be changed.
Further, the ring illumination device 1 can control the intensity and color of the light collected at the intersection P by controlling the lighting, extinction, and intensity of the LED groups 2R, 2G, and 2B.

The ring illumination device 1 according to the present embodiment has the following effects.
(1) Since the LED groups 2R, 2G, and 2B, the prism 3, and the reflecting mirror 4 are formed in an annular shape along the periphery of the optical axis A in the objective lens 10, the reflecting mirror 4 includes the LED group 2R, Light emitted from 2G and 2B and synthesized by the prism 3 can be condensed radially toward the optical axis A. Therefore, the ring illumination device 1 can perform uniform illumination.
(2) Since the prism 3 is easily formed in an annular shape, the ring illumination device 1 can perform uniform illumination with a simple configuration.
(3) Since the LED groups 2R, 2G, and 2B, the prism 3, and the reflecting mirror 4 are sequentially arranged in a direction away from the optical axis A, each color light emitted from the LED groups 2R, 2G, and 2B is emitted. The light can be condensed by the reflecting mirror 4 after being emitted in a direction away from the optical axis A.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
FIG. 4 is a schematic cross-sectional view showing a ring illumination device 1A according to the second embodiment of the present invention.
In the following description, parts that have already been described are assigned the same reference numerals and description thereof is omitted.
In the first embodiment, the ring illumination device 1 includes the unit 5, and the unit 5 includes the LED groups 2 </ b> R, 2 </ b> G, and 2 </ b> B and the prism 3. On the other hand, in this embodiment, the ring illumination device 1A includes a unit 5A as shown in FIG. 4, and the unit 5A includes LED groups 2R, 2G, and 2B, a prism 3, and LED groups 2R and 2G. , 2B and the prism 3 are different in that they include three collimating lenses 6 that collimate the respective color lights emitted from the LED groups 2R, 2G, 2B.

In this embodiment as well, the same operations and effects as those of the first embodiment can be achieved, and the following operations and effects can be achieved.
(4) By collimating each color light emitted from the LED groups 2R, 2G, and 2B with each collimating lens 6, the reflecting mirror 4 can efficiently collect each color light. Therefore, the illumination efficiency of the ring illumination device 1A can be improved.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.
FIG. 5 is a schematic cross-sectional view showing a ring illumination device 1B according to the third embodiment of the present invention.
In the said 1st Embodiment, the ring illuminating device 1 was provided with the reflective mirror 4 as a condensing element. On the other hand, in this embodiment, the ring illumination device 1B is different in that it includes a first reflecting mirror 41 and a second reflecting mirror 42 as a condensing element, as shown in FIG.

The ring illumination device 1 </ b> B includes each LED 2, a prism 3, a first reflecting mirror 41, and a second reflecting mirror 42. The LED 2, the prism 3, and the first reflecting mirror 41 are configured as an integrated unit 5B.
Among the LEDs 2, the LED groups 2R, 2G, and 2B that emit the same type of colored light are arranged in an annular shape at predetermined intervals along the periphery of the optical axis A in the same plane that is substantially orthogonal to the optical axis A. Has been. The LED groups 2R, 2G, and 2B are sequentially arranged in a direction away from the optical axis A from the LED group 2R that emits red light having a long wavelength to the LED group 2B that emits blue light having a short wavelength. .

  The prism 3 is formed in a triangular cross section having an incident end face 3A and an exit end face 3B, and is formed in an annular shape along the periphery of the optical axis A. Then, the prism 3 emits the combined light in the −Z axis direction. The prism 3 is formed to have substantially the same diameter as the LED groups 2R, 2G, and 2B, and is disposed on the −Z axis direction side of the LED groups 2R, 2G, and 2B.

The first reflecting mirror 41 has a reflecting surface 41 </ b> A that reflects the light synthesized by the prism 3, and is formed in an annular shape along the periphery of the optical axis A. The first reflecting mirror 41 is formed to have substantially the same diameter as the LED groups 2R, 2G, 2B and the prism 3, and is disposed on the −Z axis direction side of the prism 3. That is, the LED groups 2R, 2G, 2B, the prism 3, and the first reflecting mirror 41 are formed to have substantially the same diameter, and are sequentially arranged along the optical axis A.
The reflection surface 41A has a curved shape in which the end on the −Z-axis direction side protrudes on the opposite side of the optical axis A and becomes a surface substantially parallel to the optical axis A toward the + Z-axis direction. The light emitted from the light is reflected in the direction away from the optical axis A.

The second reflecting mirror 42 has a reflecting surface 42A that collects light at the intersection P by reflecting the light reflected by the first reflecting mirror 41, and is formed in an annular shape along the periphery of the optical axis A. Yes. Further, the second reflecting mirror 42 is formed with a larger diameter than the first reflecting mirror 41, and is disposed along a plane on which the first reflecting mirror 41 is disposed.
The reflecting surface 42A has a curved shape in which an end on the + Z-axis direction side protrudes toward the optical axis A side and becomes a surface substantially parallel to the optical axis A toward the −Z-axis direction. Then, the light reflected by the reflection surface 41A and the reflection surface 42A is collected at the intersection P.

In this embodiment as well, the same operations and effects as those of the first embodiment can be achieved, and the following operations and effects can be achieved.
(5) Since the LED groups 2R, 2G, 2B, the prism 3, and the first reflecting mirror 41 are formed to have substantially the same diameter and are arranged in order along the optical axis A, ring illumination The enlargement of the apparatus 1B can be suppressed.
(6) Since the first reflecting mirror 41 reflects the light synthesized by the prism 3 in the direction away from the optical axis A, each color light emitted from the LED groups 2R, 2G, and 2B is reflected on the optical axis. After being emitted in a direction away from A, the light can be condensed by the second reflecting mirror 42.

[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to the drawings.
FIG. 6 is a schematic cross-sectional view showing a ring illumination device 1C according to the fourth embodiment of the present invention.
In the first embodiment, the ring illumination device 1 includes the prism 3 as a synthesis element. On the other hand, in the present embodiment, the ring illumination device 1C is different in that it includes a Kester prism 7 as a synthesis element, as shown in FIG.

The ring illumination device 1 </ b> C includes each LED 2, a Kester prism 7, and a reflecting mirror 4. The LED 2 and the Kester prism 7 are configured as an integrated unit 5C.
Among the LEDs 2, the LED groups 2R, 2G, and 2B that emit the same type of colored light are arranged in an annular shape at predetermined intervals along the periphery of the optical axis A in the same plane that is substantially orthogonal to the optical axis A. Has been. The LED groups 2R, 2G, and 2B are sequentially arranged in a direction away from the optical axis A from the LED group 2R that emits red light having a long wavelength to the LED group 2B that emits blue light having a short wavelength. .
The LED groups 2R, 2G, and 2B are arranged so that the incident angles of the respective color lights to the Kester prism 7 are substantially the same. That is, the emission directions of the colored lights by the LED groups 2R, 2G, and 2B are substantially the same in the same plane including the optical axis A.

  The Kester prism 7 is formed in a cross-sectional triangle shape having an incident end face 7A on which each color light emitted from the LED groups 2R, 2G, and 2B is incident and an exit end face 7B that emits the combined light, and an optical axis A It is formed in an annular shape along the periphery of. Further, the Kester prism 7 is formed to have substantially the same diameter as the LED groups 2R, 2G, and 2B, and is disposed on the −Z axis direction side of the LED groups 2R, 2G, and 2B.

  The Kester prism 7 is constituted by joining four members each having a different refractive index, and a dichroic film is vapor-deposited on two of the joining surfaces (thick line in FIG. 6). Of the dichroic films, the dichroic film deposited on the joint surface on the optical axis A side functions as a dichroic mirror that transmits red light and reflects green light (hereinafter, referred to as a first dichroic mirror 71). The dichroic film deposited on the joining surface on the reflecting mirror 4 side functions as a dichroic mirror that transmits green light and reflects blue light (hereinafter referred to as a second dichroic mirror 72).

In the following description, the end face other than the entrance end face 7A and the exit end face 7B of the Kester prism 7, that is, the end face on the −Z-axis direction side is simply referred to as an end face. A description will be given assuming that a non-joint surface, that is, a joint surface between the first dichroic mirror 71 and the second dichroic mirror 72 is simply referred to as a joint surface.
Further, the joint surface is parallel to the emission end surface 7B, and the Kester prism 7 is configured such that the first dichroic mirror 71 and the second dichroic mirror 72 are parallel to the emission direction of the color light from the LED groups 2R, 2G, 2B. It is arranged to be.

The red light emitted from the LED group 2R is incident from the optical axis A side of the first dichroic mirror 71 on the incident end surface 7A, reflected by the end surface, and transmitted through the first dichroic mirror 71 and the second dichroic mirror 72. Then, it is injected from the injection end face 7B.
The green light emitted from the LED group 2G is incident from between the first dichroic mirror 71 and the second dichroic mirror 72 on the incident end surface 7A, reflected by the joint surface and the first dichroic mirror 71, and second dichroic. The light passes through the mirror 72 and is emitted from the emission end face 7B.

The blue light emitted from the LED group 2B is incident from the reflecting mirror 4 side of the second dichroic mirror 72 on the incident end face 7A, reflected by the emitting end face 7B and the second dichroic mirror 72, and emitted from the exit end face 7B. The
That is, the Kester prism 7 combines the incident color lights by reflecting them internally, and emits the combined light in the same direction away from the optical axis A along the X-axis direction.

In this embodiment as well, the same operations and effects as those of the first embodiment can be achieved, and the following operations and effects can be achieved.
(7) Since the emission direction of the colored light by the LED groups 2R, 2G, and 2B is substantially the same direction in the same plane including the optical axis A, compared with the case where a prism is employed as the combining element, Adjustment of the angles of the LED groups 2R, 2G, and 2B can be facilitated. Therefore, the manufacturing cost of the ring illumination device 1C can be reduced.

[Modification of Embodiment]
Note that the present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within the scope in which the object of the present invention can be achieved are included in the present invention. Moreover, it is free to combine the embodiments.
For example, in each of the embodiments described above, the ring illumination devices 1 to 1C include the plurality of LEDs 2 that emit three different types of color light. However, the ring illumination device emits at least two types of color light. What is necessary is just to provide an element.

In the first to third embodiments, the prism 3 is formed in a triangular cross section, but may have other cross sectional shapes such as a circular shape. In short, any prism may be used as long as it synthesizes by dispersing incident color lights and emits them in the same direction.
In each said embodiment, although the reflective mirror 4, the 1st reflective mirror 41, and the 2nd reflective mirror 4 had the reflective surface 4A, 41A, 42A of the curved shape, what is the shape of a reflective surface? It may be a simple shape. Moreover, in each said embodiment, although the condensing element was comprised by one or two members, what is necessary is just to be comprised by at least 1 member. In short, the condensing element may be any element that condenses the light synthesized by the synthesizing element at a predetermined position along the optical axis.

  The present invention can be suitably used for a ring illumination device.

1-1C ... Ring illumination device 2 ... LED (light emitting element)
3 ... Prism 4 ... Reflector (Condenser)
6 ... Parallelizing lens 7 ... Kester prism 10 ... Objective lens (optical system)
41 ... 1st reflecting mirror (light condensing element)
42 ... Second reflecting mirror (light condensing element)

Claims (6)

A plurality of light emitting elements that are arranged in a ring shape around the optical axis in the optical system and emit at least two different types of color light, a combining element that combines the color lights, and the combining element A ring illumination device comprising a condensing element for condensing light at a predetermined position along the optical axis,
Among the light emitting elements, light emitting element groups that emit the same type of colored light are arranged in an annular shape at predetermined intervals along the periphery of the optical axis in the same plane substantially orthogonal to the optical axis,
The ring illumination device, wherein the combining element and the condensing element are formed in an annular shape along the periphery of the optical axis. The ring illumination device according to claim 1,
The emission direction of the colored light by each light emitting element group is a direction inclined at different angles in the same plane including the optical axis,
The ring illumination device according to claim 1, wherein the combining element is a prism that synthesizes each incident color light by dispersing and emits the light in the same direction. The ring illumination device according to claim 2,
Each of the light emitting element groups, the combining element, and the light collecting element are formed so as to increase in diameter in order, and are arranged along the same plane substantially orthogonal to the optical axis. Ring lighting device to do. The ring illumination device according to claim 2,
The condensing element is
A first reflecting mirror for reflecting the light synthesized by the synthesis element;
A second reflecting mirror that focuses light at the predetermined position by reflecting light reflected by the first reflecting mirror;
Each of the light emitting element groups, the combining element, and the first reflecting mirror are formed to have substantially the same diameter, and are sequentially arranged along the optical axis,
The first reflecting mirror reflects light combined by the combining element in a direction away from the optical axis. The ring illumination device according to claim 1,
The emission direction of the colored light by each light emitting element group is substantially the same direction in the same plane including the optical axis,
The ring illumination device according to claim 1, wherein the combining element is a Kester prism that combines the incident color lights by reflecting them internally and emits them in the same direction. In the ring illumination device according to any one of claims 1 to 4,
A ring illumination device comprising a plurality of collimating lenses disposed between the light emitting element groups and the combining element and configured to collimate the color lights emitted from the light emitting element groups. .

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