JP4855914B2 - Ring type lighting device - Google Patents

Description

  The present invention relates to a ring illumination device that is suitably used for an optical microscope or the like.

  As shown in Patent Document 1, this type of ring illumination device has a large number of LEDs mounted inward on a ring-shaped holding frame and is attached to the periphery of a microscope barrel with a chuck or the like. Used for inspection of workpieces such as wafers.

  By the way, the current ring-type illumination device for a microscope has a configuration specialized for the field of view and the type of workpiece to be inspected. That is, the illumination conditions such as the condensing position, the diameter thereof, and the light irradiation angle are fixed so that the distance to the workpiece is constant and the workpiece can correspond to a predetermined one.

  However, in such a configuration, if the objective lens, the workpiece, or the like is changed, it is often impossible to cope with it, and it is necessary to change the illumination device every time the system is changed. As a result, it becomes necessary to increase the lineup by diversifying the lighting devices themselves.

However, when trying to correspond to a plurality of objective lenses with one illuminating device, the structure of the illuminating device tends to be complicated, and there is a risk of increasing the cost.
JP 10-149705 A

  The present invention has been made in view of such a problem, and is mainly intended to provide a ring-type illumination device that can handle a plurality of types of objective lenses and workpieces with a single unit and that has a simple configuration. It is a problem.

That is, the ring illumination device according to the present invention includes a holding frame having an observation hole in the center, an LED array in which LEDs are arranged in a ring in a slanting inward orientation around the observation hole, and the LED An annular optical member arranged in the light emission direction of the row, for illuminating a work, and a plurality of LED rows are provided concentrically and corresponding to each LED row Are arranged in a concentric manner so that the illumination modes on the workpieces by the respective LED rows are different from each other, while the outer peripheral portion of the radially inner optical member and the inner peripheral portion of the radially outer optical member in the plurality of optical members And a continuous structure.

  If it is such, the illumination aspect for every LED row | line | column, ie, the distance to a workpiece | work, an effective illumination area | region, or a light irradiation angle etc. is each comprised by the optimal thing with respect to a different objective lens or a workpiece | work. A single ring illumination device can be used for various systems. In addition, if the annular optical members are separately provided, the holding and positioning of each must be performed separately, which may lead to a complicated structure and manufacturing process. According to the present invention, the optical members are continuously provided. As a result, the holding structure can be simplified and the cost can be reduced.

  For example, in order to obtain a highly uniform illumination at a close position, it is preferable to provide two LED rows and provide the optical member corresponding to the inner LED row with a light diffusion function. In addition, such a configuration does not cause a significant increase in cost and is very easy to handle in actual use.

  According to the present invention configured as described above, for each LED row, the illumination conditions such as the distance to the workpiece, the effective illumination area, or the light irradiation angle may be optimized to correspond to the objective lens and the workpiece. This makes it possible to handle multiple types of objective lenses and workpieces with a single unit. In addition, since the optical members are made continuous to form an integral structure, it is possible to suppress the complication of the configuration and the accompanying cost increase as much as possible.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the ring illumination device 100 according to the present embodiment has an annular shape that is attached around a lens barrel K of a microscope used for inspecting a workpiece W such as a semiconductor wafer. Yes, a holding frame 1, and an LED 2 and an optical member 3 housed in the holding frame 1 are provided.

  Each part will be described in detail.

  The holding frame 1 has a disk shape with a predetermined thickness having an observation hole 1a penetrating in the thickness direction at the center, and is arranged with the bottom side facing the work W. The holding frame 1 includes a holding frame main body 11 and a thin annular engaging member 12 attached to a peripheral edge of the bottom surface of the holding frame main body 11. An annular holding groove 111 for accommodating a wiring board 4, LED 2, or optical member 3 to be described later is opened on the bottom surface of the holding frame main body 11, and the periphery of the opening extends from the outer periphery of the opening. The engaging member 12 is attached so as to protrude slightly inward.

  The LED 2 is, for example, a bullet type, and two rows are mounted concentrically on a partial annular flexible wiring board 4 having a certain width. More specifically, after the LED 2 is vertically mounted on the flexible wiring board 4 in a planar state (see FIG. 3), the flexible wiring board 4 is rounded so that the ends thereof face each other. And the LED 2 is arranged on the concave surface side.

  The truncated conical wiring board 4 with the LED 2 formed in this way is accommodated in the holding groove 111 in a radial direction. In this state, the LEDs 2 are arranged in two rows concentrically around the axis C of the observation hole 1a, and each LED 2 takes an oblique posture while facing the direction of the axis C. Therefore, since the mounting directions of the LEDs 2 with respect to the face plate portion of the flexible wiring board 4 are all set to be vertical, the angles formed by the axis C and the optical axis of each LED 2 are all the same, and from the outer LED row 2A The emitted light is collected farther than the light emitted from the inner LED row 2A.

  The optical member 3 is an annular lenticular lens disposed on the light emission direction side of the LED array 2A, and is a concentrating type that has a substantially semicircular shape in a radial cross-sectional view. In this embodiment, the optical members 3 are provided concentrically in correspondence with the respective LED rows 2A, and the inner optical member 3 has a diffusing surface 3a, for example, by sandblasting.

Further, in this embodiment, the optical member assembly 5 is formed such that these optical members 3 are continuous to form an integrated structure.
This optical member assembly 5 includes a main body 51 formed by arranging two (a plurality) of the optical members 3 described above, an outer peripheral wall 51 and an inner side extending from the outer peripheral portion and the inner peripheral portion of the main body portion 51, respectively. It consists of a peripheral wall 52. Thus, the outer peripheral wall 51 and the inner peripheral wall 52 are fitted into the holding groove 111 and fixed in the radial direction, and the engaging member 12 is engaged with the outer peripheral edge of the optical member assembly 5 to be pivoted. By being fixed in the C direction, the optical member assembly 5 is positioned without being attached to the holding groove 111 and attached.
Further, in a state where the engaging member 12 is attached, the end faces of the outer peripheral wall 51 and the inner peripheral wall 52 of the optical member assembly 5 are connected to the outer peripheral edge and the inner peripheral edge of the flexible wiring board 4 and the holding frame main body 11. It is designed to be pressed against the side.
That is, the flexible wiring board 4 and the optical member assembly 5 are inserted into the holding groove 111 in this order, and finally the engaging member 12 is attached to the holding frame body 11 so that the positioning and fixing of the LED 2 and the optical member 3 are performed at once. Is called.

Further, although not shown, the lighting device 100 includes a control device that controls the blinking of the LED 2 so that the lighting and extinguishing can be independently controlled for each LED row 2A.
Thus, when only the inner LED row 2A is turned on, the optimal illumination at a closer position, that is, illumination with high uniformity, is achieved by the diffusion function of the optical member 3 as compared with the case where light is directly emitted from the LED 2. It is constituted so that can be obtained. This is because the objective lens of the microscope is low magnification, has a short focal length, and corresponds to a workpiece W that requires uniformity.

  On the other hand, when only the outer LED row 2A is turned on, it is configured such that optimal illumination, that is, illumination with high luminance, is obtained at the condensing position. This is because the objective lens of the microscope corresponds to the workpiece W requiring high brightness with a high magnification and a long focal length.

  For reference, FIGS. 4 and 5 show brightness distributions obtained by actual experiments. When only the inner LED row 2A is lit, a wide and uniform illumination area is obtained as shown in FIG. 3, and when the outer LED row 2A is lit, as shown in FIG. Even though the effective illumination area is small, light gathers in the center and a very high illuminance can be obtained.

  Therefore, according to the illuminating device 100 which concerns on this embodiment comprised in this way, it can respond to a different system by selectively lighting either the inner side or the outer side LED row 2A. Further, the optical member 3 is made continuous to form an integrated structure, and the mounting of the integrated optical member 3 to the holding frame 1 enables the attachment and positioning of the LED 2 to the holding frame 1 at the same time. While maintaining accuracy, the structure and manufacturing process can be simplified, contributing to cost reduction.

  The present invention is not limited to the above embodiment. For example, there may be three or more LED rows, and the optical member does not necessarily have a diffusion function. Further, LEDs having different directivity characteristics may be used for each column, or LEDs having different luminances may be used. The shape of the flexible wiring board may be different for each LED column, and the LED mounting angle for each column, that is, the angle formed by the optical axis of the LED and the axis of the holding frame may be different.

  In addition, the present invention is not limited to the illustrated examples and embodiments, and various modifications can be made without departing from the gist thereof.

The schematic longitudinal cross-sectional view which shows the ring type illuminating device in one Embodiment of this invention. The schematic bottom view which shows the ring type illuminating device in the embodiment. The top view which shows the state which attached LED to the wiring board in the embodiment. Experimental data indicating illuminance when the work is illuminated by the ring illumination device in the embodiment. Experimental data indicating illuminance when the work is illuminated by the ring illumination device in the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Ring type illuminating device 1 ... Holding frame 1a ... Observation hole 2 ... LED
2A ... LED row 3 ... Optical member (lenticular lens)
W ... Work

Claims (3)

A holding frame having an observation hole in the center, an LED array in which LEDs are arranged in an annular shape around the observation hole in an obliquely inward posture, and an annular optical device disposed in the light emission direction of the LED array Comprising a member for illuminating a workpiece,
A plurality of LED rows are provided concentrically and a plurality of optical members are provided concentrically so as to correspond to each LED row, and the illumination modes of the workpieces by the LED rows are configured to be different from each other, while the plurality of optical members The ring-type illumination device in which the outer peripheral portion of the radially inner optical member and the inner peripheral portion of the radially outer optical member are made continuous.   The ring illumination device according to claim 1, wherein a plurality of LED rows are provided, and an optical member corresponding to at least the radially inner LED row has a light diffusion function.   The ring illumination device according to claim 1 or 2, wherein two LED rows are provided, and an optical member corresponding to the inner LED row is provided with a light diffusion function.