JP2020071982A - Light irradiation device and lens member - Google Patents

Abstract

To reduce loss of light emitted by an LED or LED element in what irradiates light to an arrangement direction of the LED or the LED element.SOLUTION: A light irradiation device includes: a plurality of LED 2 arranged side by side in a prescribed arrangement direction; and a plurality of lens members 3 connected in the way that each of the plurality of LED 2 is covered. Each of the lens members 3 has: a bottom surface 3a where a recess 31 receiving light emitted by the LED 2 is formed; a top surface 3b emitting light from the LED 2; and a side peripheral surface 3c totally reflecting the light from the LED 2 inward and directing it to the top surface 3b. The top surface 3b configures a partially cylindrical surface. The plurality of lens members 3 are fitted to the LED 2 in the manner that cylindrical shaft directions of the top surfaces 3b and the arrangement direction almost match.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light irradiation device and a lens member used for the same.

  2. Description of the Related Art Conventionally, for example, as a device for irradiating linear light, as shown in Patent Document 1, there is a device in which a plurality of LEDs are arranged in a line and a rod lens is provided on the light emitting side of the LEDs.

  However, in this type of light irradiation device, it is difficult to make all of the light emitted from the LED incident on the rod lens, and there is a problem that a light amount loss occurs.

JP, 2017-150875, A

  Therefore, the present invention has been made to solve the above-described problems, and in a device that emits light along the arrangement direction of LEDs or LED elements, it is possible to reduce the loss of light emitted from the LEDs or LED elements. Is the main issue.

  That is, the light irradiation apparatus according to the present invention includes a plurality of LEDs or a plurality of LED elements arranged side by side in a predetermined array direction, and a plurality of lenses provided so as to cover the plurality of LEDs or the plurality of LED elements, respectively. A member, wherein each of the lens members has a bottom surface on which a recess for receiving light emitted from the LED or the LED element is formed, and a top surface facing the bottom surface and emitting light from the LED or the LED element. And a side peripheral surface having a shape of a rotating body that totally reflects the light from the LED or the LED element inward and directs the light toward the top surface, and the top surface forms a partial cylindrical surface. The plurality of lens members are provided corresponding to the plurality of LEDs or the plurality of LED elements in such a manner that the cylindrical axis direction of their top surfaces and the arrangement direction are substantially aligned. It is characterized in. It should be noted that the fact that the cylinder axis direction of the top surface and the arrangement direction substantially match includes not only complete match but also substantially match. Here, “substantially matched” means, for example, a state in which the cylindrical axis direction is inclined within ± 10 degrees with respect to the arrangement direction.

In such a light irradiating device, the lens member has a concave portion for receiving light from the LED or LED element, and the light from the LED or LED element is totally reflected inward and directed to the top surface. Since it has a side peripheral surface that forms, the light emitted from the LED or LED element can be emitted from the top surface without loss.
Here, since the top surface of the lens member is a partially cylindrical surface, the light emitted from the top surface is condensed by the top surface only in the direction orthogonal to the cylinder axis direction. Since the cylindrical axis direction of the top surface and the arrangement direction of the LEDs or LED elements are substantially aligned with each other, insufficient illumination in the arrangement direction can be reduced.
Further, since the lens member is provided for each LED or LED element, it is possible to provide the lens member according to the number or arrangement pattern of the LEDs or LED elements. As described above, since the lens member can be used for general purposes, the degree of freedom in designing the irradiation pattern of the light irradiation device can be increased.
Furthermore, in the configuration using the conventional rod lens, it is necessary to design the housing in consideration of the thermal expansion coefficient of the rod lens, and when the longitudinal dimension of the housing is determined, the light irradiation surface Longitudinal size is restricted. Specifically, it is necessary to provide the side plates supporting both ends of the rod lens with clearances that absorb the thermal expansion amount of the rod lens, and the side plates become thicker by that amount, which shortens the longitudinal dimension of the light irradiation surface. . For example, in the case of a resin rod lens 1 m, when the temperature rises by 60 ° C., the elongation is about 4.2 mm, but considering the tolerance of the rod lens and the housing, it is necessary to take a clearance of about 10 mm as a whole. In the present invention, since the amount of thermal expansion of each lens member can be reduced, it is not necessary to provide a clearance in the side plate, or the clearance can be reduced, and the side plate can be thinned. As a result, even if the longitudinal dimension of the housing is determined, the longitudinal dimension of the light irradiation surface can be increased.

  It is desirable that the plurality of LEDs or the plurality of LED elements be arranged in a line shape or a ring shape. When arranged in a line, the length of the line-shaped light in the longitudinal direction can be changed by changing the number of arrangements. At this time, the lens member may be changed according to the number of LEDs or LED elements arranged. Further, in the case where they are arranged in a ring shape, the size of the ring-shaped light can be changed by changing the number of arrangements. At this time, the lens member may be changed according to the number of LEDs or LED elements arranged.

When viewed from a direction orthogonal to a plane in which the plurality of LEDs or the plurality of LED elements are arranged, in a state where the light emission center of the LEDs or the LED elements and the rotation center axis of the side peripheral surface are aligned, The emission center of the LED or the LED element and the cylindrical axis of the top surface may be offset from each other.
In this way, the light emission center and the cylindrical axis of the top surface are displaced from each other, so that the light emitted from the top surface is inclined with respect to the direction orthogonal to the plane in which the plurality of LEDs or the plurality of LED elements are arranged. This also makes it possible to increase the degree of freedom in designing the irradiation pattern of the light irradiation device.

  Further, the light irradiation device according to the present invention includes an LED or an LED element and a lens member provided so as to cover the LED or the LED element, and the lens member emits light emitted from the LED or the LED element. A bottom surface on which a concave portion for receiving is formed, a top surface that faces the bottom surface and emits light from the LED or the LED element, and the top by totally internally reflecting the light from the LED or the LED element. And a side peripheral surface having a shape of a rotating body facing the surface, and the top surface is configured to form a partial cylindrical surface.

In such a light irradiation device, the lens member has a concave portion for receiving the light emitted from the LED or the LED element, and the light from the LED or the LED element is totally reflected inward and directed to the top surface. Since it has a side peripheral surface that forms, the light emitted from the LED or LED element can be emitted from the top surface without loss.
Here, since the top surface of the lens member is a partially cylindrical surface, the light emitted from the top surface is condensed by the top surface only in the direction orthogonal to the cylinder axis direction. When a plurality of the light irradiation devices are combined, the illuminance insufficiency in the arrangement direction can be reduced by making the arrangement direction of the light irradiation devices substantially coincide with the cylindrical axis direction of the top surface.
In addition, various irradiation patterns can be formed depending on the number and arrangement pattern of the light irradiation devices.

  Further, the lens member according to the present invention is a lens member provided so as to cover an LED or an LED element, and a bottom surface having a concave portion for receiving light emitted from the LED or the LED element, and facing the bottom surface, A top surface that emits light from the LED or the LED element, and a side peripheral surface having a rotating body shape that totally reflects the light from the LED or the LED element inward and directs the light toward the top surface. However, the top surface is configured so as to form a partial cylindrical surface.

According to such a lens member, the lens member has a concave portion for receiving the light emitted from the LED or the LED element, and has the shape of a rotating body that totally reflects the light from the LED or the LED element inward and directs it to the top surface. Since it has a side peripheral surface, the light emitted from the LED or LED element can be emitted from the top surface without loss.
Here, since the top surface of the lens member is a partially cylindrical surface, the light emitted from the top surface is condensed by the top surface only in the direction orthogonal to the cylinder axis direction. Then, by mounting the lens member on the LED or the LED element so that the cylindrical axis direction of the top surface and the arrangement direction of the LED or LED element substantially match, it is possible to reduce the illuminance shortage in the direction orthogonal to the arrangement direction. can do.
Further, since the lens member can be generally used in accordance with the number of LEDs or the array of LED elements or the array pattern, the degree of freedom in designing the irradiation pattern of the light irradiation device can be increased.

  According to the present invention having such a configuration, in a device that emits light along the arrangement direction of the LEDs or LED elements, it is possible to reduce the loss of light emitted from the LEDs or LED elements.

It is a perspective view which shows the light irradiation apparatus of this embodiment typically. FIG. 3 is a longitudinal sectional view and a lateral sectional view schematically showing the light irradiation device of the same embodiment. It is a perspective view of the lens member of the embodiment. It is a longitudinal cross-sectional view orthogonal to the cylindrical axis direction of the lens member of the same embodiment. It is a longitudinal cross-sectional view along the cylinder axis direction of the lens member of the same embodiment. It is a schematic diagram which shows the optical path which passes the lens member of the same embodiment. It is a schematic diagram which shows the arrangement aspect of the lens member of the same embodiment. It is a longitudinal section of a lens member of a modification. It is a top view of a light irradiation device concerning a modification.

  Hereinafter, an embodiment of a light irradiation device according to the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the light irradiation device 100 of the present embodiment irradiates a surface to be irradiated of a test object (workpiece) with linear light (hereinafter, also referred to as line light), and a line sensor. An image processing device (not shown) captures the irradiated surface with an image pickup device such as an image pickup device, and the image processing device (not shown) captures defects such as scratches and dirt, and automatically inspects foreign substances in liquids or mark inspections. Used in product inspection systems that perform

  Specifically, as shown in FIGS. 1 and 2, the light irradiation device 100 includes a plurality of LEDs 2 arranged side by side in a predetermined array direction, and a plurality of lens members 3 provided so as to cover each of the plurality of LEDs 2. , A casing 4 that houses a plurality of LEDs 2 and a plurality of lens members 3.

  In the present embodiment, the plurality of LEDs 2 are surface mount LEDs (SMD), and are mounted on the substrate 20 having a rectangular shape, for example, in a straight line in a row at equal intervals.

  The plurality of lens members 3 are provided corresponding to each one LED 2. That is, they are provided in a straight line in a row along the longitudinal direction of the substrate 20 at equal intervals. The lens member 3 is solid and transparent, and has a front end surface that emits light and a side peripheral surface that forms a rotating body. The lens member 3 is made of resin such as plastic. The lens member 3 may be fixed by the casing 4, fixed by the substrate 20, or fixed by another member.

  The casing 4 has a housing space 4S that extends in the longitudinal direction and houses the substrate 20 on which the plurality of LEDs 2 are mounted and the plurality of lens members 3, and the light emitting portion 4X that emits linear light on the tip surface. Has been formed. The light emitting portion 4X of the casing 4 may be provided with a diffusion plate 5 to make the illuminance distribution of the line light emitted from the plurality of lens members 3 uniform. The diffusion plate 5 is provided on the front side (upper side) of the plurality of lens members 3 on the light emission side, and a protective cover may be provided on the light emission side surface (upper surface) of the diffusion plate 5.

  Therefore, as shown in FIGS. 3, 4 and 5, the lens member 3 of the present embodiment has a base end surface 3a which is a bottom surface having a recess 31 for receiving substantially all of the light emitted from the LED 2, and the base member 3a. It has a front end surface 3b which faces the end surface 3a and which is a top surface for emitting light from the LED 2, and a side peripheral surface 3c which totally reflects the light from the LED 2 inward and directs it toward the front end surface 3b. ..

  In the present embodiment, the opening of the recess 31 is provided in the vicinity of the light emitting surface of the LED 2 to receive almost all the light emitted from the LED 2. It is also possible to accommodate a part or all of the LED 2 inside the recess 31 to receive substantially all of the light emitted from the LED 2.

  The bottom surface 31a of the recess 31 has a convex lens shape that bulges toward the base end surface 3a, and the side surface 31b of the recess 31 is a tapered surface that gradually expands toward the base end surface 3a. In addition to the convex lens shape, the bottom surface 31a may have a concave lens shape, a flat surface, or various shapes. Further, the side surface 31b may be a surface having an equal cross-sectional shape other than the tapered surface, or may have various shapes.

  The side peripheral surface 3c has a shape of a rotating body with respect to the optical axis of the bottom surface 31a having a convex lens shape, and in the present embodiment, is a curved bulging surface formed so that its cross-sectional contour is, for example, a parabola. That is, the side peripheral surface 3c is formed such that the area of the cross-sectional contour orthogonal to the optical axis gradually increases from the base end surface 3a toward the front end surface 3b.

  In the present embodiment, as shown in FIG. 6, of the light emitted from the LED 2, almost all of the light that has passed through the side surface 31b of the recess 31 reaches the side peripheral surface 3c and is totally reflected there to be tip surface 3b. Is configured to go to. In addition, of the light emitted from the LED 2, almost all the light that has passed through the bottom surface 31a of the recess 31 is configured to go to the front end surface 3b without passing through the side peripheral surface 3c.

  As shown in FIGS. 4 and 5, in particular, the tip surface 3b of the present embodiment is configured to be a partial cylindrical surface, and is configured to function as a cylindrical lens that focuses light in one direction. Has been done.

  Here, as shown in FIG. 7, each lens member 3 has a cylindrical axis direction 3x of a tip end surface 3b thereof when viewed from a direction (hereinafter, also referred to as a light emission direction) orthogonal to a plane in which the LEDs 2 are arranged. The LEDs are mounted so as to substantially match the arrangement direction of the LEDs 2. In the present embodiment, since the LEDs 2 are linearly arranged in a line, the LEDs 3 are mounted so that the tip end surface 3b of each lens member 3 has a substantially same linear axis direction. By mounting the plurality of lens members 3 in this manner, the light emitted from the LEDs 2 by the plurality of lens members 3 is condensed in the direction orthogonal to the arrangement direction of the LEDs 2.

  Further, in the present embodiment, the cylindrical axis 3x of the tip surface 3b is configured to overlap the light emission center 2x of the LED 2 when viewed from the light emitting direction. That is, the central axis of rotation of the side peripheral surface 3c and the cylindrical axis 3x intersect. Further, the rotation center axis of the side peripheral surface 3c is configured to pass through the light emission center 2x of the LED 2. As a result, the optical axis becomes a straight line from the light emission center 2x of the LED 2 to the illuminated surface. The cylindrical axis 3x is the central axis of the paraxial radius of curvature of the tip surface 3b.

  According to the light irradiating device 100 of the present embodiment configured as described above, the lens member 3 has the concave portion 31 for receiving the light emitted from the LED 2, and the light from the LED 2 is totally reflected inward so that the front end surface 3b (top) is formed. Since it has the side peripheral surface 3c in the shape of a rotating body that is directed toward the surface), the light emitted from the LED 2 can be emitted from the tip surface 3b without loss.

  Here, since the front end surface 3b of the lens member 3 is a partial cylindrical surface, the light emitted from the front end surface 3b is condensed by the front end surface 3b only in the direction orthogonal to the cylindrical axis direction. Since the cylindrical axis direction of the tip end surface 3b and the arrangement direction of the LEDs 2 are substantially aligned with each other, it is possible to reduce the illuminance shortage in the arrangement direction.

  Further, since the lens member 3 is provided for each LED 2, the lens member 3 can be provided according to the number of LEDs 2 arranged and the arrangement pattern. As described above, since the lens member 3 can be used for general purposes, the degree of freedom in designing the irradiation pattern of the light irradiation device 100 can be increased.

  The present invention is not limited to the above embodiment.

  For example, as shown in FIG. 8, the cylindrical axis 3x of the distal end surface 3b may be displaced from the rotation center axis of the side peripheral surface 3c. That is, the emission center 2x of the LED 2 and the cylindrical axis 3x of the tip surface 3b may be displaced from each other when viewed from the light emission direction. With this configuration, the light emitted from the tip surface 3b can be inclined with respect to the direction orthogonal to the plane in which the LEDs 2 are arranged, and this also increases the degree of freedom in designing the irradiation pattern of the light irradiation device 100. You can

  For example, when a plurality of LEDs 2 are arranged in three rows, in the central LED row, the emission center 2x and the cylindrical axis 3x of the top surface are aligned when viewed from the light emission direction, and the LED rows on both sides are It is conceivable that the emission center 2x and the cylindrical axis 3x of the tip surface 3b are displaced so that the light emitted from the lens member 3 is inclined toward the center.

  Although the top surface of the above embodiment is a partial cylindrical surface having a single curvature, it may be a partial cylindrical surface having different radii of curvature at the central portion and the peripheral portion of the top surface, for example. Further, the entire top surface may be a partial cylindrical surface, or a part thereof may be a partial cylindrical surface.

In addition, in the above-described embodiment, the plurality of LEDs 2 are linearly arranged in a line to irradiate linear light. However, as shown in FIG. 9, the plurality of LEDs 2 are arranged in an annular shape to form a ring. It may be one that irradiates a light beam. In this case, in order to collect the plurality of LEDs 2 arranged in an annular shape at the center of the annular shape, it is conceivable to shift the cylindrical axis 3x of the tip surface 3b of the lens member 3 inward from the light emission center 2x of the LED 2.
The cylindrical axis does not have to be a straight line, for example, a curved line in accordance with the arrangement of the LEDs 2 in an annular shape.

  Further, the arrangement direction of the plurality of LEDs 2 is not limited to the linear shape or the annular shape, and may be a curved or bent curved shape.

  Furthermore, in the above-described embodiment, the light irradiation device using the surface-mounted LED has been described, but the light irradiation device uses a so-called chip-on-board (COB) in which a plurality of LED chips are mounted on a metal substrate. Is also good. In this case, the concave portion formed on the bottom surface of the lens member is configured to accommodate one or a plurality of LEDs on the metal substrate. Further, the LED may be one in which a lens is integrally formed by potting, or one in which the lens is provided in the vicinity of the LED or the LED element.

  In addition, in the above-described embodiment, a light irradiation device including a plurality of LEDs 2 has been described, but a light irradiation device including one LED 2 and one lens member 3 may be used. In this case, a plurality of light irradiation devices can be combined to form various irradiation patterns depending on the number of arrangements and the arrangement pattern. At this time, by making the arrangement direction of the light irradiation device substantially coincide with the cylindrical axis direction of the front end surface 3b, it is possible to reduce the illuminance shortage in the direction orthogonal to the arrangement direction.

  Besides, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

100 ... Light irradiation device 2 ... LED
3 ... Lens member 31 ... Recessed portion 3a ... Bottom surface (base end surface)
3b ... Top surface (tip surface)
3c ... side peripheral surface 2x ... light emission center 3x ... top surface cylindrical axis

Claims (5)

A plurality of LEDs or a plurality of LED elements arranged side by side in a predetermined array direction,
A plurality of lens members provided to cover each of the plurality of LEDs or the plurality of LED elements,
Each of the lens members has a bottom surface formed with a recess for receiving light emitted from the LED or the LED element, a top surface facing the bottom surface and emitting light from the LED or the LED element, the LED or And a side peripheral surface having a rotating body shape that totally reflects the light from the LED element inward and directs the light toward the top surface, and the top surface is configured to form a partial cylindrical surface,
The light irradiating device, wherein the plurality of lens members are provided corresponding to the plurality of LEDs or the plurality of LED elements in such a manner that the cylindrical axis direction of the top surfaces thereof and the arrangement direction substantially match.   The light irradiation device according to claim 1, wherein the plurality of LEDs or the plurality of LED elements are arranged in a line shape or a ring shape.   In a state where the light emission center of the LED or the LED element and the rotation center axis of the side peripheral surface are aligned with each other when viewed from a direction orthogonal to a plane in which the plurality of LEDs or the plurality of LED elements are arranged. The light irradiation device according to claim 1 or 2, wherein a light emission center of the LED or the LED element and a cylindrical axis of the top surface are displaced from each other. LED or LED element,
A lens member provided so as to cover the LED or the LED element,
The lens member is
A bottom surface formed with a recess for receiving light emitted from the LED or the LED element;
A top surface facing the bottom surface and emitting light from the LED or the LED element;
And a side peripheral surface having a rotating body shape that totally reflects the light from the LED or the LED element inward and directs the light toward the top surface,
The light irradiating device, wherein the top surface is configured to form a partial cylindrical surface. A lens member provided so as to cover the LED or the LED element,
A bottom surface formed with a recess for receiving light emitted from the LED or the LED element;
A top surface facing the bottom surface and emitting light from the LED or the LED element;
And a side peripheral surface having a rotating body shape that totally reflects the light from the LED or the LED element inward and directs the light toward the top surface,
The lens member, wherein the top surface is configured to form a partial cylindrical surface.