JP6654956B2 - Light irradiation device - Google Patents

Description

  The present invention relates to a light irradiation device in which a plurality of LED substrates are arranged.

For example, in an exposure apparatus for an electronic circuit board, a mercury lamp is conventionally used as a light source (see Patent Document 1). In recent years, in order to reduce the environmental burden by reducing power consumption and emission of CO ₂ , extending the life of the light source, and not using mercury, it has been required to replace the mercury lamp in the exposure apparatus with an LED light source. is there.

  However, since the light output of one LED in the ultraviolet light is smaller than that of a mercury lamp, it is necessary to use a large number of LEDs in order to obtain the same light output. Surface light source. Since the LED is a diffused light source, in order to efficiently irradiate the fly-eye lens of the exposure apparatus with ultraviolet light, the ultraviolet light emitted from each LED is emitted in a substantially parallel direction by a lens, and each light is emitted by a condenser lens. It is necessary to condense substantially parallel ultraviolet light to the fly-eye lens.

  With such a configuration, the substrate is exposed even if one or about two of the LED boards on which a plurality of LEDs are arranged are turned off or the irradiance is reduced. On the exposure surface, irradiance unevenness as a whole can be suppressed.

  However, in the case where the light emitted from each LED is particularly ultraviolet light, if the lens array is made of resin, its function is impaired due to its deterioration, so that it is necessary to use a material such as glass.

  However, since the specific gravity of glass is greater than that of resin, it is very heavy to produce a single lens array having an area required for an exposure apparatus, for example. For this reason, it is difficult to produce a large single lens array due to manufacturing limitations and cost issues. In addition, when the lenses are connected by an adhesive, there is a problem in that the positional accuracy between the lenses is deteriorated and the adhesive is deteriorated by ultraviolet light, so that the long-term durability is deteriorated. Therefore, it is formed by dividing into a plurality of lens arrays smaller than the required area.

  However, if the lens array is divided into a plurality of parts, it is necessary to divide and form the LED substrate accordingly. Furthermore, in order to suppress the irradiance unevenness as a whole and to emit uniform light from the whole, the optical axes of each lens array and each LED board must be aligned with high precision.

  For this reason, when trying to manufacture a light irradiation device having a large-area surface light source such as used in an exposure device, the labor required for assembly is greater than that of a mercury lamp, and the manufacturing cost is increased. Difficult to do.

JP 2010-33094 A

  The present invention has been made in view of the above-described problems, and has a plurality of optical axes formed on a plurality of lens arrays and a plurality of optical axes of a plurality of LEDs arranged on a plurality of LED substrates only by simple alignment. It is an object of the present invention to provide a light irradiation device that can accurately match the optical axis of a lens and can realize a large-area surface light source at low cost.

  That is, the light irradiation device according to the present invention includes four irradiation units each including an LED substrate and a lens array arranged on the LED substrate, and four irradiation units each pressed against the four irradiation units. A positioning member having four arrangement reference planes for disposing the unit at a predetermined position, wherein the LED substrate is arranged based on an LED reference end face and a distance from the LED reference end face with respect to the LED reference end face. A plurality of LEDs, wherein the lens array includes a lens reference end surface, and a plurality of lenses arranged based on a distance from the lens reference end surface with respect to the lens reference end surface. The irradiation unit and four arrangement reference planes are arranged so as to be four-fold rotationally symmetric, and one arrangement reference plane is provided for one arrangement reference plane. Wherein the LED reference end surface and the lens reference end surface in elevation unit is pressed.

  In such a case, only one type of irradiation unit needs to be manufactured to make the light irradiation device a large-area surface light source. Furthermore, by simply pressing each irradiation unit in the same direction in the circumferential direction with respect to the placement reference plane of the positioning member, multiple LEDs and multiple lenses are arranged at the same position, and their optical axes coincide. Can be done. Therefore, despite being divided into a plurality of elements in order to obtain a large-area surface light source, the irradiance unevenness of the entire surface light source is suppressed, and at the time of assembling, the optical axis alignment between each LED and each lens is reduced. Cost can be significantly reduced. For this reason, with the light irradiation device according to the present invention, it is possible to realize a large-area surface light source required for an exposure device with an LED at low cost, for example.

  In order to easily arrange the two-dimensional positions of the plurality of LEDs and the two-dimensional positions of the plurality of lenses so that the two-dimensional positions coincide with each other, and to accurately match the respective optical axes, the arrangement reference The surface is composed of a first side surface and a second side surface orthogonal to the first side surface, and the LED reference end surface is orthogonal to the first LED end surface pressed against the first side surface and the first LED end surface. And a second LED end face pressed against the second side face, wherein the lens reference end face is orthogonal to the first lens end face pressed against the first side face and the first lens end face. What is necessary is just to consist of a 2nd lens end surface pressed against a 2nd side surface.

  In order to make it easy to use a large-area surface light source and simplify the work of attaching the irradiation unit to the positioning member, the positioning member is formed in a cross shape, and the first side surface and the second side surface are formed in each quadrant. What is necessary is just to be formed.

  In order to reduce the number of operations for fixing the LED board and the lens array so that the optical axis of the LED and the lens coincide with each other, and to prevent the lens array from being broken by applying a large force, What is necessary is just to be further provided with the pressing body attached to the upper surface of the LED substrate and the positioning member and pressing and fixing both of the lens arrays of the adjacent irradiation units.

  Even if there is a heat sink that dissipates the heat generated by each LED board, there is no need to turn the power supply cable for supplying power to each LED board to the outside of the heat sink. For example, a casing structure that accommodates each irradiation unit and the heat sink In order to prevent the LED from becoming complicated and to reduce the manufacturing cost, the apparatus further comprises heat sinks provided below the four irradiation units, wherein the heat sinks are connected to the four LED substrates. It suffices if four through holes are provided for passing the supply cable, and each through hole is arranged so as to be four times rotationally symmetric.

  In order to further improve the maneuverability when guiding the power supply cable from the upper surface to the lower surface of the heat sink, and to reduce the manufacturing cost required for assembly, each of the LED substrates is provided with the LED reference end surface. Has a power supply connector to which the power supply cable is connected on the opposite side, and in a state where the LED board is pressed against the positioning member, the through hole is arranged outside the LED board and near the power supply connector. It should just be done.

  As a specific configuration for simplifying the attachment of the power supply cable also on the lower surface of the heat sink, the heat sink is plate-shaped and provided on the side of the heat sink where the irradiation unit is not provided. And a relay unit that is configured to be connected to the LED board by the power supply cable and to be connected to an external power supply by a power cable.

  As described above, according to the light irradiation device of the present invention, it is only necessary to press the irradiation unit of the same shape against the positioning member while aligning its orientation with respect to the rotation direction. The optical axes of the lenses can be matched. Therefore, radiation irradiation unevenness as a surface light source can be reduced only by a simple mounting operation, and a large-area surface light source can be manufactured at low cost by using an LED.

FIG. 1 is a schematic perspective view showing a light irradiation device according to one embodiment of the present invention. FIG. 4 is a schematic top view showing a state where a cover, a condenser lens, and a lens array of the light irradiation device are removed in the embodiment. FIG. 4 is a schematic top view showing a state where a cover and a condenser lens of the light irradiation device are removed in the embodiment. The schematic diagram which shows the structure of the LED board in the embodiment. FIG. 2 is a schematic diagram illustrating a structure of a lens array according to the first embodiment. FIG. 2 is a schematic perspective view showing the structure of a positioning member according to the embodiment. FIG. 4 is a schematic cross-sectional view showing a fixing structure of the lens array in the same embodiment. FIG. 3 is a schematic perspective view showing wiring from an LED substrate to a relay unit on the lower surface side of the light irradiation device in the same embodiment. FIG. 2 is a schematic perspective view showing wiring from a relay unit to a power supply connector on a lower surface side of the light irradiation device in the same embodiment. FIG. 3 is a schematic perspective view showing a relay unit in the same embodiment. FIG. 4 is a schematic diagram showing a light irradiation device according to another embodiment of the present invention.

  A light irradiation device 100 according to one embodiment of the present invention will be described with reference to the drawings. The light irradiation device 100 of the present embodiment is a surface light source used as a light source of an exposure device used for manufacturing an electronic circuit board, for example, and a light emitting area required for the exposure device as shown in FIGS. Is divided into four, and each of the divided light emitting areas is taken by four irradiation units 2.

  More specifically, the light irradiation device 100 includes an irradiation unit IR on the upper surface side and a power supply unit SP on the lower surface side.

  The irradiation unit IR is provided on the heat sink 1, a water-cooled heat sink 1 formed in a substantially plate shape, four irradiation units 2 arranged on the upper surface of the heat sink 1 and having a light emitting surface of a substantially square shape. A positioning member 3 serving as a reference for arranging the four irradiation units 2 at predetermined positions, a condenser lens 4 provided above the irradiation unit 2 and the positioning member 3, and a casing 5 covering each member. ing.

  The irradiation unit 2 includes an LED substrate 6 and a lens array 7 provided on the LED substrate 6 so as to overlap with each other. The LED substrate 6 includes a printed substrate 61 having at least two end faces orthogonal to each other. It comprises LEDs 62 arranged in a square lattice, and supports (positioning member 3, pressing member 8, holding member 81, fixing member 82, which will be described later) for supporting the lens array 7.

  The printed circuit board 61 has an LED reference end face that serves as a reference for a two-dimensional coordinate position of the plurality of LEDs 62 on the printed circuit board 61. The LED reference end surface is a surface pressed against the side surface of the positioning member 3, and includes a first LED end surface 6A and a second LED end surface 6B orthogonal to the first LED end surface 6A. As shown in the enlarged view of FIG. 4, the printed board 61 has a shape having a bulging portion in which one corner of a square bulges outward in plan view. The first LED end face 6A and the second LED end face 6B form end faces opposite to the bulging portion. A power supply connector 63 to which a power supply cable C for supplying power to the plurality of LEDs 62 is connected is provided on the bulging portion on the same surface as the LEDs 62. The heat sink 1 has a through hole 11 near the power connector 63 for guiding the power supply cable C to the lower surface of the heat sink 1. As shown in FIGS. 1 to 3, through holes 11 are formed in the heat sink 1 corresponding to the four irradiation units 2, respectively, and are arranged so as to be rotated four times around the center point as the center of rotation. is there.

  The plurality of LEDs 62 emit ultraviolet light, and are arranged in a square lattice based on the distance from the LED reference end face with respect to the LED reference end face. That is, the two-dimensional coordinate position of each LED 62 on the printed circuit board 61 is set at the distance in the vertical direction from the first LED end surface 6A and the distance in the vertical direction from the second LED end surface 6B.

  As shown in the enlarged view of FIG. 5, the lens array 7 is a thin plate having a substantially square face plate portion in which the same number of lenses 71 as the LEDs 62 are two-dimensionally arranged and integrally formed of glass, for example. The lens array 7 has a lens reference end surface serving as a reference for a two-dimensional coordinate position of each lens 71 in the lens array 7. The lens reference end surface includes a first lens end surface 7A pressed against a side surface of the positioning member 3, and a second lens end surface 7B orthogonal to the first lens end surface 7A. That is, the two-dimensional coordinate position of the lens 71 in the lens array 7 is set by a distance in a direction perpendicular to the first lens end face 7A and a distance in a direction perpendicular to the second lens end face 7B. The first lens end face 7A and the second lens end face 7B are provided as protrusions protruding outward. In this embodiment, three lens arrays 7 are stacked on one LED substrate 6.

  The positioning member 3 is provided on the heat sink 1 so as to form a substantially cross shape. More specifically, the positioning member 3 is formed by ridges extending in two orthogonal directions. The ridge includes a base portion 31 slightly thicker than the printed board 61 in a cross-sectional view, and a protruding portion 32 that is thinner than the base portion 31 and protrudes upward from the center of the base portion 31. The LED reference end surface of the LED substrate 6 is pressed against the side surface of the base 31, and the lens reference end surface of the three lens arrays 7 is pressed against the side surface of the protrusion 32.

  That is, the positioning member 3 is pressed against the four irradiation units 2, and has, on the side surface, four arrangement reference planes for disposing the four irradiation units 2 at predetermined positions. The arrangement reference plane includes a first side surface 3A and a second side surface 3B orthogonal to the first side surface 3A. The first side face 3A and the second side face 3B are formed for each quadrant. The first side surface 3A and the second side surface 3B are configured as surfaces having a step by the side surface of the base portion 31 and the side surface of the protruding portion 32. The first side surface 3A and the second side surface 3B are arranged so as to be rotated four times around the center of the positioning member 3 as a center point.

  The positioning and assembly on the heat sink 1 by the irradiation unit 2 and the positioning member 3 configured as described above will be described.

  The four irradiation units 2 have the same shape and configuration as described above, and are arranged on the heat sink 1 so as to be rotationally symmetric four times about the center of the positioning member 3 as a center point. More specifically, in each LED board 6, the first LED end face 6A is pressed against the first side face 3A of the positioning member 3 (base portion 31), and the second LED end face 6B is pressed against the first side surface 3A of the positioning member 3 (base portion 31). It is pressed against the two side surfaces 3B. In this way, the positions of the LED board 6 and the LEDs 62 arranged on the LED board 6 on the heat sink 1 are determined based on the positioning member 3. The LED reference end surface is pressed against the side surface of the positioning member 3 while rotating each LED board 6 by 90 °.

  After the LED substrate 6 is positioned, the first lens end surface 7A of the lens array 7 is pressed against the first side surface 3A of the positioning member 3 (projection 32) and the second lens end surface 7B of the first lens array 7 Is pressed against the second side surface 3B of the positioning member 3 (projection 32). At this time, the lens array 7 is placed in a state of being bridged between the base 31 and the mounting portion (the same height as the base 31) of the holder 81. Thus, the position of the lens 71 on the heat sink 1 is determined based on the positioning member 3. The direction of each lens array 7 is such that the lens reference end surface is pressed against the side surface of the positioning member 3 while rotating by 90 °. Such an assembling operation is similarly performed for the second and third lens arrays 7.

  By doing so, the LED reference end surface serving as a reference for the position of each LED 62 and the lens reference end surface serving as a reference for the position of each lens 71 with respect to the positioning member 3 can be accurately arranged at the design position. Therefore, the two-dimensional coordinate positions of each LED 62 and each lens 71 on the heat sink 1 can be substantially matched. That is, since the optical axis of each LED 62 and the optical axis of each lens 71 coincide in all combinations, the surface light source is closest to the design state and irradiance unevenness can be reduced.

  Further, as shown in FIG. 7, after the lens array 7 is positioned, it is fixed by pressing from the upper surface side to the lower surface side of the positioning member 3. More specifically, a pressing member 8 for pressing and fixing the lens array 7 downward is provided on the upper surface of the projecting portion 32 of the positioning member 3, and the pressing member 8 is sandwiched between the pressing member 8 and the upper surface of the base portion 31. The pressing force is directly applied only to the three lens arrays 7 thus obtained. The pressing body 8 is made of a resin washer and a screw. Between the washer and the lens array 7, a metal shim having a diameter larger than that of the washer and a thinner plate (in order to prevent the washer from being deteriorated by ultraviolet light). (Not shown). The washer has a diameter larger than the width of the projection 32, and the outer edge of the washer is protruded outward when attached to the upper surface of the projection 32. Thereby, both of the adjacent lens arrays 7 can be pressed and fixed at the same time by one washer, and the number of screws required to fix each lens array 7 can be reduced, thereby reducing the assembly cost. The lens array 7 is also fixed by a fixing member 82 provided on the holding body 81 and having the same structure as the pressing body 8.

  Next, the power supply unit SP will be described with reference to FIGS.

  The power supply cable C connected to the power connector 63 of each LED board 6 uses an FFC cable, and is guided to the lower surface of the heat sink 1 through the through hole 11. As shown in FIG. 8, two power supply cables C guided from the two LED boards 6 to the lower surface of the heat sink 1 are connected to one relay unit 9.

  In the relay unit 9, one first connector 91 is provided on each of the back surface and the front surface of the board, and a second connector 92 is provided on the front surface of the board. A power supply cable C connected to the LED board 6 is connected to the first connector 91, and a power cable L connected to the external power connection connector OC is connected to the second connector 92.

  As shown in FIG. 10, a pair of first connectors 91 are arranged so as to be vertically symmetrical with respect to the board, and as shown in FIG. The power supply cable C led from 11 can be connected without bending. On the other hand, the power supply cable C guided from the through hole 11 can be connected to the first connector 91 on the rear side by bending.

  With the light irradiation device 100 of the present embodiment configured as described above, only one type of the LED substrate 6 and the lens array 7 needs to be manufactured in order to provide a large-area surface light source. Furthermore, the LED substrate 6 and the lens array 7 are accurately positioned at the design positions on the substrate by simply pressing each of the irradiation units 2 in the same direction in the circumferential direction with respect to the arrangement reference plane of the positioning member 3. can do. Then, since the LED reference end face and the lens reference end face, which are the reference of the position of each LED 62 and each lens 71, are accurately positioned by the positioning member 3, each LED 62 and a plurality of corresponding lenses 71 are arranged at the same position. Each optical axis can be matched.

  Therefore, despite the fact that the light source is divided into a plurality of parts so as to form a large area surface light source, the irradiance unevenness of the entire surface light source is suppressed and the optical axis alignment between each LED 62 and each lens 71 during assembly is performed. Labor and cost can be greatly reduced.

  For this reason, a large-area surface light source required for an exposure apparatus can be realized at low cost by using LEDs.

  Further, since the heat sink 1 is provided with the through hole 11, the power supply cable C connected to each LED unit can be guided to the lower surface side of the heat sink 1 through the through hole 11. Therefore, there is no need to connect the power supply cable C by bypassing the outside of the heat sink 1, so that no gap is formed in the casing 5, and for example, measures against leakage of ultraviolet rays and the like are facilitated. Further, since the power supply cable C guided to the back side of the heat sink 1 is connected by the relay unit 9, the wiring to the external power supply can be improved.

  From these facts, with the light irradiation device 100 of the present embodiment, a large area surface light source can be realized, the manufacturing cost can be significantly reduced, and the light irradiation device 100 is replaced with a mercury lamp currently used as a light source in an exposure apparatus. Becomes possible.

  Other embodiments will be described.

  The number of lens arrays 7 stacked on one LED substrate 6 is not limited to three, but may be one, two, or four or more. Further, the shape and structure of the lens array 7 may be different or the same.

  The arrangement shape of the positioning member 3 and the directions of the LED reference end surface and the lens reference end surface are not limited to those described in the above embodiment. It is preferable that the positioning member 3 be an integral member in order to increase the positional relationship between the LED 62 and the lens 71 with high accuracy, but may be formed separately as long as positional accuracy within an allowable range is obtained. For example, as shown in FIG. 11, a square frame-shaped positioning member 3 may be used, and an arrangement reference surface may be formed on the inner surface of the positioning member 3. In this case, the LED reference end face and the lens reference end face may be set not on the inner peripheral end face but on the outer peripheral end face with respect to the rotation center. In short, the irradiation units 2 may be arranged so as to be four times rotationally symmetric. The rotational symmetry of the positioning member 3 may be partially distorted. For example, the rectangular frames are not all continuous as in the example of FIG. 11, but may be interrupted on the way. Further, as shown in FIG. 11, the shape of the ridge forming the positioning member 3 does not have to be different for each portion where the LED substrate 6 and the lens array 7 are in contact with each other, but may be the same.

  Further, the number of relay units may be one, and the power supply connector may be arranged at the center in a state where each irradiation unit is arranged.

  Further, the LEDs arranged on the LED substrate may be bullet-shaped LEDs or LED chips. The arrangement of the LEDs and lenses is not limited to a square lattice, but may be various arrangements such as a regular triangular lattice or a regular hexagonal lattice.

  Further, the light irradiation apparatus of the present invention can be used for applications requiring various large-area surface light sources other than the exposure apparatus.

  In addition, various embodiments may be combined or modified without departing from the spirit of the present invention.

100 Light irradiating device 1 Heat sink 2 Irradiation unit 3 Positioning member 31 Base 32 Projecting portion 3A First side surface 3B of placement reference surface The second side surface 4 of the arrangement reference surface 4... The condenser lens 5... The casing 6... The LED substrate 61.
63 Power connector 6A First LED end surface 6B Second LED end surface 7 Lens array 71 Lens 7A First lens end surface 7B Second lens end surface 8 .Pressing body 9 ... relay unit

Claims (7)

Four irradiation units each including an LED substrate and a lens array arranged on the LED substrate;
A positioning member having four arrangement reference planes to which the four irradiation units are pressed, and to arrange the four irradiation units at predetermined positions,
The LED substrate includes an LED reference end face, and a plurality of LEDs arranged based on a distance from the LED reference end face with respect to the LED reference end face,
The lens array includes a lens reference end face, and a plurality of lenses arranged based on a distance from the lens reference end face with respect to the lens reference end face,
Four irradiation units and four arrangement reference planes are arranged so as to be four times rotationally symmetric,
The light irradiation device, wherein the LED reference end surface and the lens reference end surface of one irradiation unit are pressed against one arrangement reference surface. The arrangement reference plane includes a first side surface and a second side surface orthogonal to the first side surface,
The LED reference end face includes a first LED end face pressed against the first side face, and a second LED end face pressed against the second side face while being orthogonal to the first LED end face,
2. The lens reference end face includes a first lens end face pressed against the first side face, and a second lens end face that is orthogonal to the first lens end face and pressed on the second side face. 3. Light irradiation device.   The light irradiation device according to claim 2, wherein the positioning member is formed in a cross shape, and the first side surface and the second side surface are formed in each quadrant.   The light irradiation device according to claim 3, further comprising a pressing body attached to an upper surface of the positioning member and pressing and fixing both of the lens arrays of the adjacent irradiation units. Further comprising a heat sink provided below the four irradiation units,
The heat sink has four through holes for passing a power supply cable connected to the four LED boards,
The light irradiation device according to any one of claims 1 to 4, wherein each through hole is arranged so as to be four times rotationally symmetric. The LED board includes a power connector to which the power supply cable is connected on a side opposite to the LED reference end face,
The light irradiation device according to claim 5, wherein the through hole is arranged outside the LED board and near the power connector when the LED board is pressed against the positioning member. The heat sink is plate-shaped,
The heat sink further includes a relay unit provided on a side where the irradiation unit is not provided,
The light irradiation device according to claim 5, wherein the relay unit is configured to be connected to the LED board by the power supply cable and to be connected to an external power supply by a power cable.