JP7223451B1 - lighting equipment - Google Patents

Abstract

Kind Code: A1 A lighting device used for testing a solid-state imaging device, which does not require a drive device such as an actuator and has a relatively simple and compact structure, can realize a wide illuminance dynamic range. A plurality of light sources 121 to 125 arranged in a row, and a plurality of dimming regions 141 to 145 arranged on the light irradiation side of the plurality of light sources 121 to 125 and having different light transmittance are arranged in a row. a light source unit 18 with dimming means 16 arranged in a . Furthermore, by combining the uniformizing means 36 such as the light guide plate 20, it is possible to irradiate uniform light. [Selection drawing] Fig. 2

Description

The present invention relates to an illumination device that can be used, for example, for optical testing of solid-state imaging devices.

Solid-state image sensors (image sensors), which are semiconductor integrated circuits such as CCD and CMOS, utilize the characteristics of converting light into electrical signals to be used in digital still cameras, video cameras, mobile phone cameras, and advanced driving of automobiles. It is widely used in various sensors such as support systems and various other industrial equipment. A solid-state imaging device requires an optical test (optical property evaluation) to determine whether its photoelectric property is normal after wafer completion or before product shipment. In recent years, in the optical test of solid-state imaging devices, throughput is emphasized, and it is common to optically test a large number of image sensors at the same time. In order to test a large number of image sensors at the same time, it is required to irradiate a wide range in which the image sensors are arranged side by side with light having a high uniformity of illuminance.

2. Description of the Related Art In order to perform an optical test of a solid-state imaging device, various lighting devices have been developed that can irradiate light with high uniformity of illuminance over a wide range (see, for example, Patent Document 1). In the illumination device of Patent Document 1, an illumination optical system having a light source, a large number of lenses and filters for generating light from the light source as light with a uniform illuminance distribution, and illumination light passing through the illumination optical system is applied to an object to be inspected. and an optical system including a projection optical system for projecting onto the solid-state imaging device, and illuminating the light-receiving surface of the solid-state imaging device to be inspected with uniform illumination light. Conventionally, halogen lamps have been widely used as light sources for lighting devices. In recent years, however, the use of semiconductor light-emitting elements such as light-emitting diodes, laser diodes, and the like, which emit less carbon dioxide and have a longer life, is expanding in various fields, not limited to light sources for lighting devices.

On the other hand, as a lighting device that irradiates light uniformly in a plane, a plurality of light emitting diodes are arranged at the same intervals on the end surface of the light guide plate, and when the light from the light emitting diodes is incident from the end surface of the light guide plate, the light is guided. It is also known that the light diffuses while being repeatedly reflected within the light plate, and the entire light emitting surface (light guide plate surface) emits light uniformly (see, for example, Patent Document 2). This light guide plate type illumination device is thin and lightweight, and can emit light evenly with little illuminance unevenness. etc. is used.

Japanese Patent No. 5181174 JP 2010-112735 A

As mentioned above, the demand for solid-state image sensors for various industrial equipment is increasing, and their performance is improving as they are used in a wide range of fields. Widening the dynamic range is progressing so that it can be perceived in an extremely wide range of illuminance up to illuminance. Therefore, an illumination device used for optical tests of solid-state imaging devices is also required to illuminate in a wide illuminance range.

As a means for adjusting the illuminance in conventional lighting devices such as those disclosed in Patent Documents 1 and 2, illuminance adjustment by current control of a light source such as a light-emitting diode and a fixed neutral density filter (ND filter) installed in the optical path are used. Illuminance adjustment by switching in steps, illuminance adjustment by continuously switching a variable neutral density filter, illuminance adjustment by a variable diaphragm, and the like have been performed. Further, for example, a technique is also used in which a plurality of neutral density filters having transmittances set in stages are supported by a turret and rotated by a stepping motor or the like to insert a neutral density filter with a predetermined transmittance into the optical path. ing.

However, in illuminance adjustment by current control of a light source such as a light emitting diode, there is a problem that various characteristics become unstable when driven at a low current due to crystal defects and variations in impurities in the matrix constituting the semiconductor light emitting element. Furthermore, since the lower limit of the driving current of the light-emitting diode is recommended to be about 10% of the rated current, when the high illuminance side is set to tens of thousands of lux as described above, illuminance adjustment by current control alone will not It was not possible to achieve the desired low illumination. Therefore, illuminance adjustment is performed in combination with an ND filter, a variable aperture, etc. In this case, a wide illuminance dynamic range can be expected, but on the other hand, an actuator is required as a drive mechanism for switching between these ND filters. , the number of parts is large and the structure has a mechanical drive mechanism, which makes the device large, complicated, and costly. There is a problem that the efficiency of the test is lowered due to the time required to move the filter or the like.

Further, when a light guide plate type illumination device as disclosed in Patent Document 2 is used for optical testing of a solid-state imaging device, in addition to the above-mentioned problems such as the need for a driving mechanism, the light guide plate end surface In order to irradiate the light with the illuminance adjusted, an optical fiber is inevitably required, but since propagation loss occurs in the optical fiber, etc., it has been difficult to realize illumination with a high illuminance of several tens of thousands of lux.

The present invention has been made in view of the above-mentioned conventional problems, and one of its purposes is to provide a relatively simple and compact structure that does not require a driving device such as an actuator for driving and controlling a neutral density filter or a variable aperture. To provide a lighting device capable of realizing a wide illuminance dynamic range.

In order to solve the above problems, the present invention provides a plurality of light sources 121 to 125 arranged in a row, and a plurality of dimming lights having different light transmittances installed on the light irradiation side of the plurality of light sources 121 to 125. A light source unit group comprising a light source unit 18 having dimming means 16 in which regions 141 to 145 are arranged in a row, and a plurality of light source units 18 are arranged in parallel or in a matrix. The illumination device 10 includes a light source unit group 44a in which the light sources 121 to 125 of the light source units 18 arranged in parallel are set with light of different wavelengths.

Further, the present invention includes a plurality of light sources 121 to 125 arranged in a row, and a plurality of dimming regions 141 to 145 arranged on the light irradiation side of the plurality of light sources 121 to 125 and having different light transmittances. and the light attenuation means 16 arranged in a shape, and the arrangement of the light attenuation regions of the light attenuation means 16 of the light source unit 18 is such that the light attenuation regions with high transmittance are positioned near the center. The illuminating device 10 is composed of a lighting device 10 in which a dimming region is set in which the transmittance is gradually lowered toward the end portion side. The light source unit 18 may be configured by combining one or a plurality of units.

Further, it includes a light source unit group 44 configured by arranging a plurality of light source units having the same arrangement of the dimming regions 141 to 145 of the dimming means 16 in series, parallel or matrix. You can do it.

Further, a homogenizing optical system 26 that homogenizes the light from the light source unit 18 and irradiates the irradiation target may be further provided.

Further, the uniformizing optical system 36 may have a light guide plate 20 that allows the light from the light source unit 18 to enter from the side end portion and irradiate the uniform light on the surface.

Further, a control means 22 for controlling light emission of the light sources 121 to 125 of the light source unit 18 may be provided.

Also, the control means 22 may adjust the light emission of the light sources 121 to 125 by referring to a predetermined table.

Further, the control means 22 uses an n-order polynomial (n is an integer of 2 or more) obtained by approximation from the relationship between the current flowing through the light sources 121 to 125 of the light source unit 18 and the illuminance emitted by the lighting device 10. may be used to adjust the light emission of the light source.

Further, the light source unit 18 may have a light blocking portion 50 installed between the adjacent light sources 121 to 125. FIG.

According to the illumination device of the present invention, a plurality of light sources arranged in a row and a plurality of dimming regions arranged in a row on the light irradiation side of the plurality of light sources and having different light transmittances are arranged. Since the light source unit includes the dimming means, it is possible to achieve a wide illuminance dynamic range with a simple and compact structure that does not require a driving device such as an actuator. As a result, it is possible to provide an illuminating device that can also be put to practical use for optical tests of wide dynamic range solid-state imaging devices.

In addition, a configuration including a light source unit group configured by arranging a plurality of light source units having the same arrangement of the dimming regions of the dimming means in series, in parallel, or in a matrix , a wider illuminance dynamic range can be expected.

Also, a light source unit group configured by arranging a plurality of light source units in parallel or in a matrix, wherein the light sources of the light source units arranged in the parallel direction are set to emit light of different colors. By adopting a configuration including the light, it is possible to change and irradiate light of a plurality of colors (wavelengths) with only one lighting device, and the practicality of the lighting device can be improved.

Further, by further including a homogenizing optical system that homogenizes the light from the light source unit and irradiates the irradiation target, it is possible to generate illumination light with high uniformity. It can be suitably put into practical use for lighting that requires uniform light.

In addition, the uniformizing optical system is configured to have a light guide plate that allows the light from the light source unit to enter from the side end portion and irradiate the uniform light on the surface, thereby generating illumination light with high uniformity. It is possible to concretely realize a lighting device capable of realizing a wide illuminance dynamic range at the same time with a compact and simple configuration.

Further, in the arrangement of the dimming regions of the dimming means of the light source unit, the dimming region with high transmittance is set at the central position, and the dimming region with gradually lower transmittance is set toward the end. With this configuration, when the light source units are arranged in a row, leakage of light with high illuminance from the dimming region with high transmittance affects the light from the dimming region with low transmittance. can be reduced, and accurate illuminance adjustment and high uniformity can be achieved at the same time.

In addition, by further comprising control means for controlling light emission of the light sources of the light source unit, on/off control and current adjustment of each light source are performed to perform illuminance adjustment such that a desired illuminance can be easily obtained. be able to.

Further, by configuring the control means to adjust the light emission of the light source with reference to a predetermined table, it is possible to realize the illuminance adjustment that can easily and reliably obtain the desired illuminance.

Further, the control means controls the light emission of the light source according to an n-order polynomial (n is an integer of 2 or more) obtained by approximation from the relationship between the current flowing through the light source of the light source unit and the illuminance emitted by the lighting device. By adjusting, it is possible to achieve illuminance adjustment capable of obtaining the desired illuminance with higher accuracy.

In addition, the light source unit has a light shielding portion between adjacent light sources, thereby preventing light from leaking from the dimming regions having different transmittances. High uniformity can be ensured at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS It is schematic structure explanatory drawing of the illuminating device which concerns on the 1st Embodiment of this invention. 2 is a partially enlarged view of a light source unit of the illumination device of FIG. 1; FIG. FIG. 2 is a perspective view showing the appearance of the lighting device in FIG. 1; FIG. 2 is a partially enlarged explanatory view of a cross section of the illumination device of FIG. 1; 2 is a graph showing the illuminance range of the lighting device of FIG. 1; 2 is another embodiment of the light source unit of the illumination device of FIG. 1; 2 is an example of a table used for control means of the lighting device of FIG. 1. FIG. FIG. 2 is a table for explaining an example of measured current and illuminance applied to a light source of a light source unit in the lighting device of FIG. 1 ; FIG. 4 is a graph showing an example of the relationship between the current and the illuminance when the control means of the lighting device of FIG. 1 adjusts the illuminance using a sixth-order polynomial. FIG. 6 is a partially enlarged explanatory view of a cross section of a lighting device according to a second embodiment of the present invention; FIG. 11 is an exploded perspective explanatory view showing a part of the light source unit group of the lighting device of FIG. 10;

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a lighting device of the present invention will be described below with reference to the accompanying drawings. The lighting device according to the present invention is a lighting device whose illuminance can be changed/adjusted according to an irradiation target, and is used as a lighting device for test light illumination for testing optical devices such as image sensors, which are solid-state imaging devices. It can be preferably used. 1 to 7 show a first embodiment of the illumination device of the invention. As shown in FIGS. 1, 2, and 4, the illumination device 10 according to this embodiment includes a plurality of light sources 121 to 125 and a dimming means 16 in which a plurality of dimming regions 141 to 145 are arranged. has at least one light source unit 18 .

Further, in this embodiment, a light guide plate 20 that homogenizes the light from the light source unit 18 for planar illumination and a control means 22 that controls the plurality of light sources 121 to 125 are provided. As shown in FIGS. 1, 3, and 4, the light source unit 18, the light guide plate 20, and other elements constituting the device are housed in a housing 24, and the illumination surface of the light guide plate 20 is illuminated from the opening of the housing 24. is set up facing the outside. The housing 24 is formed, for example, in the shape of a hollow rectangular box, and includes support means for supporting the light source unit 18 and the light guide plate 20 . In this embodiment, the housing 24 includes a base plate 28 which is detachably fixed with screws or the like to the opening side of a housing body 26 which is open on one side, and which has a regular octagonal opening. a light source unit fixing block 30 fixed on the light source unit fixing block 30 via a screw or the like, and a light guide plate holding block that cooperates with the base plate 28 to fix the peripheral edge of the light guide plate 20 in a clamping manner. 32 and . A cushion material 34 is interposed in the contact portion of the light guide plate holding block 32 with the light guide plate 20 . The light guide plate holding block 32 is formed with a space 32a for receiving the light source unit 18, and the base plate 28 and the light guide plate holding block 32 cooperate with each other via a cushion material 34 to fix the light source unit 18 vertically. ing.

The light guide plate 20 is a light homogenizing means 36 that homogenizes and irradiates the light from the plurality of light sources 121 to 125 of the light source unit 18 . In this embodiment, the light guide plate 20 is made of a hard material such as acrylic resin which is transparent and has high light transmittance, and is formed in a regular octagonal plate shape. The light guide plate 20 has one surface serving as an illumination surface, and a reflecting sheet 38 that reflects light on the back surface thereof. The reflective sheet 38 is attached to the rear surface of the light guide plate 20 by being attached to a rear surface plate 40 made of aluminum, for example. A diffuser plate 42 is installed on the illumination surface side of the light guide plate 20 . A light source unit 18 is arranged at each of the side end portions corresponding to the eight sides of the regular octagon of the light guide plate 20 . The light from the light source unit 18 is incident on the light guide plate 20 from each side end, and the light is diffused within the light guide plate 20 to uniformize the light and illuminate the entire illumination surface. In the configuration in which the light source units 18 are installed at all the side edges of the light guide plate 20 as in this embodiment, it is possible to generate illumination light with high uniformity of illuminance particularly near the center. It should be noted that the light guide plate 20 may be formed in a square shape or other polygonal shape. The light source units 18 are not limited to being installed on all eight side edges of the light guide plate 20, and the light source units 18 may be installed on some of the side edges. Further, the homogenizing means 36 may be any means as long as the illuminance of the incident light can be uniformly homogenized. For example, the homogenizing means 36 is not limited to the configuration using the light guide plate 20, and may be configured using an integrator optical system such as a fly-eye lens or a rod integrator. At this time, a plurality of types of light guide plates and integrator optical systems may be used in combination.

In this embodiment, a plurality of light source units 18 are arranged in series at each side end of the light guide plate 20 as the uniformizing means 36 to form a light source unit row, that is, a series light source unit group 44 . That is, the light source unit group 44 formed in a straight line is arranged in a regular octagonal frame shape along the side end portion of the light guide plate 20, ie, along the outer contour.

As shown in FIG. 2, the plurality of light sources 121 to 125 of each light source unit 18 are arranged in rows to form a predetermined light source group. In this embodiment, the light sources 121 to 125 are, for example, extremely small and high-brightness light-emitting diodes that can realize point-like light sources, and are fixed in a row on the substrate 46 . Five light sources 121 to 125 are arranged in one light source unit 18 and arranged in a straight line at regular intervals. All the five light sources are composed of light-emitting diodes with the same brightness and performance. A light source 124 and a fifth light source 125 are used. As described above, the plurality of light source units 18 are arranged in series. The first to fifth light sources 121 to 125 of the plurality of light source units 18 are repeatedly arranged in a straight line. The light sources 121 to 125 are installed on the substrate 46 such that, for example, when the light source unit 18 is installed on the side edge of the light guide plate 20 , they are positioned substantially in the center of the plate thickness of the light guide plate 20 . The rear surface side of the substrate 46 opposite to the surface on which the light source is installed is in close contact with the light source unit fixing block 30 fixed to the base plate 28 via a heat conducting sheet 48 for heat dissipation. The lower end of the substrate 46 is supported on the base plate 28, and the upper end of the substrate 46 is inserted into the groove portion of the light guide plate holding block 32 and is abutted and fixed via the cushion material 34. As shown in FIG. Although the plurality of light sources are arranged in a row in this embodiment, they may be arranged in a plurality of rows. Further, the light source is not limited to a light emitting diode, and may be another light source such as a semiconductor laser.

As shown in FIGS. 2 and 3, the light reduction means 16 is installed on the light irradiation side of the plurality of light sources 121 to 125, and can adjust the illuminance of the light from the light sources to irradiate the light guide plate 20 and the like. Optical means. The dimming means 16 is configured by arranging a plurality of dimming regions 141 to 145 having different light transmittances in a line corresponding to the arrangement configuration of the plurality of light sources 121 to 125 . The dimming regions 141 to 145 are optical density adjusting regions that can individually change the illuminance of the light from each light source, and can be said to be a dimming filter portion that transmits the light after dimming. In this embodiment, the dimming region includes a region that transmits 100% of light, that is, a region with a transmittance of 100% (optical density=OD0). Therefore, the concept of the dimming region includes a so-called dimming region where light is dimmed with a transmittance of less than 100% and a dimming/transmissive region including a transmissive region with a transmittance of 100%. In the drawing, the dimming region is indicated by cross hatching.

In this embodiment, the dimming regions 141 to 145 have a transmittance of 100% (optical density = OD0), 10% (OD1), 1% (OD2), and 0.1% (OD3) in one light source unit 18. , 0.01% (OD4) are set and arranged in series to form a group of neutral density filters. In each light source unit 18, dimming regions 141-145 are formed corresponding to the light sources 121-125 on a one-to-one basis. First to fifth dimming regions 141 to 145 are set. As will be described later, the plurality of light source units 18 (light source unit group 44) turns on (turns on) the light source corresponding to one (or a plurality of) desired transmittance attenuation regions, and other light attenuation regions. By turning off the corresponding light source, the illuminance of the light emitted from the light guide plate 20 can be adjusted. In addition, a wide illuminance dynamic range is achieved by adjusting the current that lights the light source.

As shown in FIG. 2, the arrangement of the first to fifth dimming regions 141 to 145 is such that the transmittance of the first dimming region 141 is 0.1 % and the transmittance of the first dimming region 142 is 0.1% in order from the end side. 10%, the transmittance of the third dimming region 143 is set to 100 %, the transmittance of the fourth dimming region 144 is set to 1 %, and the transmittance of the fifth dimming region 145 is set to 0.01%. . By arranging the plurality of light source units 18 in series, the first to fifth dimming regions are repeatedly arranged. That is, in the arrangement of a plurality of dimming areas of the dimming means of each light source unit 18, the dimming area with high transmittance is set at the central position, and the dimming area with gradually lower transmittance is set toward the end side. It has a configuration in which areas are set.

The array configuration of the plurality of dimming regions of the dimming means is not limited to the configuration described above, and may basically be arbitrary. As an arrangement configuration of a plurality of dimming regions different from the above, for example, they are arranged in order of decreasing transmittance (100%, 10%, 1%, 0.1%, 0.01%). A configuration is also conceivable. In this case, when a plurality of light source units 18 are arranged and configured, the plurality of dimming regions are 100%, 10%, 1%, 0.1%, 0.01%, 100%, 10%, 1 %, . . . are arranged repeatedly. At this time, the dimming region with the lowest transmittance (0.01%) is arranged next to the dimming region with the highest transmittance (100%). When the corresponding light source is turned on, leakage of light from the turned-on light source passes through the adjacent dimming region with high transmittance, resulting in an increase in overall illuminance. On the other hand, by arranging the plurality of dimming regions 141 to 145 as in the present embodiment, leakage of light from the dimming regions with high transmittance is transferred to light from the dimming regions with low transmittance. It can have a relatively low impact and is an advantageous arrangement for achieving lower illumination and thus a wider illumination dynamic range.

In order to reduce leakage from adjacent light sources, as shown in FIG. 6, each light source unit 18 may be provided with a light blocking portion 50 between the adjacent light sources 121 to 125. FIG. The light shielding part 50 is formed integrally with, for example, a substrate or a dimming means or the like in a plate shape, limits the irradiation direction of each light source, and reduces interference with dimming regions corresponding to adjacent light sources. A configuration in which a light shielding portion is provided between adjacent light sources slightly increases the manufacturing cost, but it is thought that the influence of light leakage to the adjacent dimming regions is reduced. You can have more freedom.

The dimming means 16 has a plurality of dimming regions 141 to 145 formed by vapor-depositing an optical thin film on, for example, a transparent plate having high translucency, a thin thickness, and a long side. Therefore, the dimming means 16 is composed of a dimming plate member 52 in which a plurality of dimming filters having different transmittances, that is, dimming regions are arranged. The dimming means 16 composed of the dimming plate member 52 has one plate surface arranged in close contact with or in close contact with the light sources 121 to 125, and has the other plate surface in close contact with or in close contact with the side edge of the light guide plate 20. is installed. The length of the dimming plate member 52 is set to substantially the same length as the substrate 46, that is, substantially the same length as the length of one side of the light guide plate 20, and the first to the first light source units of one light source unit group 44 are set to have substantially the same length as one side of the light guide plate 20. Five dimming regions 141 to 145 are integrally formed. The transmittance of the dimming region is not limited to that described above and may be arbitrary. Also, the number of dimming regions may be arbitrary as long as it is plural. In order to simplify the device configuration and control of the light source, the dimming regions may be configured to have, for example, about 3 to 6 types of transmittance and be repeatedly arranged. Further, each light source unit 18 is not limited to a configuration in which one light source is associated with one light-reducing region with one transmittance. For example, a plurality of light-emitting diodes are arranged for one light-reducing region. The number of light sources and the number of dimming regions may be the same or different.

The control means 22 is electrically connected to the substrate 46 of the light sources 121 to 125 of the light source unit 18, and is a light source control means for controlling light emission by on/off control of the light sources 121 to 125 and current adjustment. In this embodiment, the control means 22 is controlled to select one of the light sources corresponding to each dimming region of the dimming means 16 of the plurality of light source units 18 and adjust lighting and current. That is, as shown in FIG. 5, when illuminating in a high illuminance range, each light source unit 18 has a third light source corresponding to the dimming region 143 with a high transmittance (for example, 100%=OD0). The illuminance is adjusted by lighting only 123 and adjusting the current of the third light source. Conversely, when illuminating in a range of low illuminance, each light source unit 18 turns on only the fifth light source 125 corresponding to the dimming region 145 with a low transmittance (for example, 0.01%=OD5). , the illuminance is adjusted by adjusting the current of the fifth light source. Similarly, by selecting a light source corresponding to the dimming region (OD0 to OD4) set to the transmittance of the target illuminance range and adjusting the current input to the light source, a multi-step illuminance range can be realized with one device configuration, and lighting with a wide illuminance dynamic range can be realized. Specifically, the first illuminance range R1 with high illuminance turns on the third light source 123 corresponding to the dimming region 143 with a transmittance of 100% (OD0), and adjusts the current to achieve a range of 32700 Lx to 2140 Lx. Illumination can be adjusted up to a range. In the second illuminance range R2 with the next highest illuminance, the second light source 122 corresponding to the dimming area 142 with a transmittance of 10% (OD1) is turned on, and the current is adjusted so that the illuminance ranges from 3280 Lx to 213 Lx. can be adjusted. In the third illuminance range R3 with the next highest illuminance, the fourth light source 124 corresponding to the dimming region 144 with a transmittance of 1% (OD2) is turned on, and the current is adjusted to a range of 451 Lx to 29.3 Lx. You can adjust the brightness up to At this time, the transmittance of the dimming region of the third illuminance range R3 is 1/10 of the transmittance of the dimming region of the second illuminance range R2. This illuminance range is due to the influence of leakage of light from the dimming region with high . The fourth and fifth illuminance ranges R4 and R5 also have illuminance ranges as shown in the figure due to the influence of light leakage from adjacent light sources. In the fourth illuminance range R4 with the next highest illuminance, the first light source 121 corresponding to the dimming region 141 with a transmittance of 0.1% (OD3) is turned on, and the current is adjusted to 67.8 Lx to 4 Illuminance can be adjusted up to a range of 0.46Lx. In the fifth illuminance range R5, which has the lowest illuminance, the fifth light source 125 corresponding to the dimming region 145 with a transmittance of 0.01% (OD4) is turned on, and the current is adjusted to obtain a range of 14.92 Lx to 0.05 Lx. Illuminance can be adjusted up to a range of 98Lx. In addition, since the adjustable illuminance range overlaps in each illuminance range, it is possible to continuously change and adjust a wide illuminance dynamic range (32700 Lx to 0.98 Lx). In this embodiment, one light source is lit in each light source unit 18, but since a plurality of light source units 18 are installed and incident on the light guide plate 20, the illuminance from the light guide plate is within a predetermined range. can obtain uniform illumination light. In addition, the light source of each light source unit 18 is not limited to a control method in which only one corresponding to one dimming region is lit, and a plurality of light sources corresponding to dimming regions having a plurality of transmittances are simultaneously turned on to increase the illuminance. It is good also as a control method which adjusts.

In this embodiment, the control means 22 is, for example, a computer, and controls the light emission of the first to fifth light sources 121 to 125 with reference to a predetermined table. That is, the control means 22 comprises a computer equipped with an arithmetic processing unit, a storage device such as a memory or a hard disk, and an input/output device such as a mouse, a display, or a touch panel, and performs predetermined control according to a program stored in advance in the storage device. conduct. In the storage device of the control means 22, for example, the illuminance, the light source to be lit, and the current to be input to the light source are stored as a table as shown in FIG. By simply selecting the desired illuminance with the control means 22, the table is referred to, and the light sources that are automatically turned on and the current that is input to the light sources are controlled, so that the illumination can be adjusted. As shown in FIG. 7, for example, in order to obtain an illuminance of L _N lux, the control means 22 inputs current I _N amperes to the M-th light source (M=integer of 1 to 5) to adjust lighting. controls light emission of the light source of the light source unit.

The control of the light sources 121 to 125 of the light source unit 18 by the control means 22 is not limited to using the table, and any other control method may be used. For example, the control means 22 uses an nth-order polynomial (n is an integer of 2 or more) obtained by approximating the relationship between the current flowing through the light source and the illuminance of the light emitted from the lighting device in advance. may be adjusted and controlled. In the case of control using such an nth-order polynomial, illuminance adjustment can be performed continuously with higher accuracy than when using a table.

For example, assuming that the illuminance is f(x) and the current flowing through the light source is x, the relationship between the illuminance f(x) and the current x can be approximated by a polynomial expression such as Equation (1). When the current control of the light source is actually performed by the control means 22, the n-order polynomial of Equation 2 can be used as an approximation of the above Equation 1 up to n dimensions (where n is an integer of 2 or more). .

Specifically, while changing the electric current to flow through the first to fifth light sources 121 to 125 of the illumination device 10 configured as described above, the illuminance at each electric current value is measured as shown in FIG. In addition, in the table of FIG. 8, some values are omitted. Then, the coefficients a ₀ to a _n of the approximation formula 2 are calculated from the actual measured values of the illuminance and the current. For example, three coefficients a ₀ , a ₁ , and a ₂ are obtained for second-order approximation, and the approximate expression is calculated by obtaining six coefficients a ₀ to a ₆ for sixth-order approximation. can be done. After the n-th order polynomial f(x) is determined, the control means 22 such as a computer stores in advance the n-th order polynomial f(x) and a calculation program for obtaining its solution (current x). A well-known program may be used as a calculation program for obtaining the solution of the nth-order equation. When adjusting the illuminance when using the lighting device 10, the numerical value of the desired illuminance is entered into the n-order polynomial f(x) to find the solution and calculate the current x to be applied to the light source, The illuminance can be adjusted by controlling the current x to flow through any one of the first to fifth light sources 121 to 125 . It should be noted that although there are at most n solutions (x) for the n-th degree polynomial, there are various boundary conditions that result in an appropriate value for the current of a light source composed of a light-emitting diode (for example, the current is a positive real number, the maximum value of the light-emitting diode rated current, etc.). The higher the order n, the more accurately the illuminance can be adjusted. The order n should be determined in consideration of balance.

The graph of FIG. 9 is an example of a graph showing the relationship between illuminance and current when using a sixth-order polynomial as an approximation formula obtained based on the measured values of FIG. FIG. 9A is a graph in the case of adjusting the current when controlling by lighting only the third light source 123 corresponding to the third dimming region 143 with a transmittance of 100% (OD0). Similarly, FIG. 9B is a graph in the case of adjusting the current when controlling by lighting only the second light source 122 corresponding to the second dimming region 142 with a transmittance of 10% (OD1). FIG. 9(c) is a graph in the case of adjusting the current when controlling by turning on only the fourth light source 124 corresponding to the fourth dimming region 144 with a transmittance of 1% (OD2). FIG. 8D is a graph in the case of adjusting the current when controlling by lighting only the first light source 121 corresponding to the first dimming region 141 with a transmittance of 0.1% (OD3). FIG. 9E is a graph in the case of adjusting the current when controlling by lighting only the fifth light source 125 corresponding to the fifth dimming region 145 with a transmittance of 0.01% (OD4). Furthermore, FIG. 9F shows the relationship between the normalized illuminance and the current, with the horizontal axis representing the current (mA) and the vertical axis representing the normalized illuminance (%) obtained by standardizing the measured illuminance in FIG. graph. In FIG. 9(f), the sixth-order polynomials for controlling the first to fifth light sources corresponding to any of the dimming regions (OD0 to OD4) are approximate to each other, and are overlapped on the graph. . In this way, when the control means 22 adjusts the illuminance using the n-th order polynomial, the light source to be automatically turned on is selected only by inputting and selecting the desired illuminance, and the n-th order polynomial corresponding to the light source is selected. By controlling the current input to the light source, it is possible to continuously adjust the illuminance with high accuracy and a wide dynamic range.

Next, a second embodiment of the illumination device of the present invention will be described with reference to FIGS. 10 and 11. FIG. The same reference numerals are given to the same members as in the above-described embodiment, and detailed description thereof will be omitted. The illumination device according to the present embodiment, as in the above embodiment, includes a plurality of light sources 121 to 125 arranged in a row and a dimming means 16 in which a plurality of dimming regions 141 to 145 are arranged. It has a plurality of units 18 . The arrangement of the first to fifth light sources 121 to 125 in each light source unit 18, the arrangement of the transmittance of the first to fifth dimming regions 141 to 145 of the dimming means 16, etc. are configured substantially the same as in the above embodiment. ing. The same applies to the configuration in which the light source unit group 44a composed of a plurality of light source units 18 is arranged in the shape of a regular octagonal frame along the side edge of the regular octagonal light guide plate, that is, along the outer contour.

In the present embodiment, the light source unit group 44a has substantially the same configuration of each light source unit 18 as in the above embodiment, but is configured by arranging a plurality of light source units 18 in a matrix. Further, in the light source unit 44a, the light source units 18 arranged in the series direction (horizontal direction H) are set to emit light of the same color (wavelength), and are arranged in the parallel direction (vertical direction V). The light source units are set so as to emit light with different colors (wavelengths).

Specifically, in the light source unit group 44a, the first to fifth light sources 121 to 125 of the plurality of light source units 18 constituting the light source unit 44a are fixed on the same substrate 46 at predetermined intervals in a matrix. there is In the light source unit row (45G) arranged in series (horizontal direction H) in the first row from the top, the first to fifth light sources 121 to 125 of each light source unit 18 are set to emit green light. It is In the light source unit row (45R) arranged in series (horizontal direction H) in the second row from the top, the first to fifth light sources 121 to 125 of each light source unit 18 are set to emit red light. It is In the light source unit row (45 W) arranged in series (horizontal direction H) in the third row from the top, the first to fifth light sources 121 to 125 of each light source unit 18 are set to emit white light. It is In the light source unit row (45B) arranged in series (horizontal direction H) in the fourth row from the top, the first to fifth light sources 121 to 125 of each light source unit 18 are set to emit blue light. It is The light source units arranged in the parallel direction (vertical direction V) in this manner are set with light sources of four different colors. In the plurality of light source units 18 arranged in parallel, the first light sources 121 are linearly arranged in the parallel direction, and the first dimming regions 141 are linearly formed. Similarly, the second light sources 122 and the second dimming regions 142 are arranged vertically, the third light sources 123 and the third dimming regions 143 are arranged vertically, and the fourth light sources 124 are arranged vertically. and the fourth dimming regions 144 are vertically arranged side by side, and the fifth light sources 125 and the fifth dimming regions 145 are vertically arranged side by side. In other words, in the dimming means 16 in which the dimming regions 141 to 145 with different transmittances are arranged, a plurality of light sources of different colors (four colors) are arranged in parallel in each of the dimming regions 141 to 145. It can be said that it is a configuration. Also in this embodiment, as shown in FIG. 6, light shielding portions may be provided between the light sources adjacent in the series direction in each light source unit 18 .

As shown in FIG. 11, the dimming means 16 of the plurality of light source units 18 of each light source unit group 44a is a single dimming plate having a width corresponding to the arrangement area of the light source units 18 arranged in a matrix. It is composed of a member 52 . That is, the first to fifth dimming regions 141 to 145 are arranged repeatedly in the series direction (horizontal direction H), and the same dimming region is set in the parallel direction (vertical direction V). Secondly, it is formed by vapor-depositing an optical material on a single transparent plate. Further, the dimming plate member 52 constituting the dimming means 16 is arranged close to or in close contact with the side end portions of the sides of the light guide plate 20 on the irradiation surface side of each light source. In addition, in FIG. 11, a part of the dimming plate member 52 is cut out for the sake of explanation.

The substrate 46 is electrically connected to a control means 22 for controlling light emission by controlling on/off of the light sources 121 to 125 of the light source unit 18 and current adjustment. In this embodiment, the control means 22 turns on only one specific color (wavelength) light source, i.e., any one of green, red, white, and blue light sources to illuminate with light of the selected color. be able to. Furthermore, by lighting a combination of light sources of a plurality of colors by the control means 22, it is possible to illuminate by changing to light of a greater number of colors (wavelengths). At the same time, the same control means 22 can adjust the illuminance of each color by adjusting the current supplied to each light source using the same table or n-order polynomial as in the above embodiment. As a result, it is possible to illuminate while changing to many colors and at the same time realize a wide illuminance dynamic range with only one lighting device. The colors (wavelengths) set for the light sources of the plurality of light source units arranged in parallel are not limited to four colors, and may be set to two colors, three colors, or five or more colors. In the above embodiment, the plurality of light source units 18 constituting the light source unit groups 44 and 44a are arranged so that the arrangement of the dimming regions of the dimming means is the same. It is good also as arranging and comprising a different thing.

The illumination device of the present invention described above is not limited to the configuration of the above-described embodiment only, and may be arbitrarily modified without departing from the essence of the present invention described in the claims. .

INDUSTRIAL APPLICABILITY The illumination device of the present invention can be used, for example, as an illumination device for testing optical devices such as solid-state imaging devices with a wide dynamic range, or as an illumination device that performs illumination while changing the illuminance in various other wide illuminance ranges. .

10 lighting device 121-125 light source 141-145 dimming area 16 dimming means 18 light source unit 20 light guide plate 22 control means 24 housing 26 housing body 28 base plate 30 light source unit fixing block 32 light guide plate holding block 34 cushion material 36 uniform conversion means 38 reflection sheet 40 rear plate 42 diffusion plate 44, 44a light source unit group 46 substrate 50 light shielding portion 52 plate

Claims (9)

a plurality of light sources arranged in a row;
a light source unit provided with a light reduction means in which a plurality of light reduction regions having different light transmittances are arranged in a row, and which is installed on the light irradiation side of the plurality of light sources;
A light source unit group configured by arranging a plurality of light source units in parallel or in a matrix,
1. A lighting device comprising a light source unit group in which the light sources of the light source units arranged in a parallel direction are set with light of different wavelengths . a plurality of light sources arranged in a row;
a light source unit provided with a light reduction means in which a plurality of light reduction regions having different light transmittances are arranged in a row, and which is installed on the light irradiation side of the plurality of light sources;
In the arrangement of the dimming areas of the dimming means of the light source unit, the dimming area with high transmittance is set at a central position, and the dimming area with gradually lower transmittance is set toward the end side. A lighting device characterized by: 3. A light source unit group comprising a plurality of light source units having the same arrangement of the light attenuation regions of the light attenuation means arranged in series, in parallel, or in a matrix. 3. The lighting device according to 1 or 2 . 4. The illumination device according to any one of claims 1 to 3, further comprising a homogenizing optical system for homogenizing the light from the light source unit and irradiating the irradiation target with the homogenized light. 5. The illumination device according to claim 4, wherein the homogenizing optical system has a light guide plate that allows the light from the light source unit to enter from a side end portion and irradiate the light uniformly on a plane. 6. The illumination device according to claim 1, further comprising control means for controlling light emission of said light source of said light source unit. 7. The illumination device according to claim 6 , wherein said control means adjusts light emission of said light source with reference to a predetermined table. The control means adjusts the light emission of the light source using an nth-order polynomial (where n is an integer of 2 or more) obtained by approximation from the relationship between the current flowing through the light source of the light source unit and the illuminance emitted by the lighting device. 7. The lighting device according to claim 6 , characterized in that: 9. The lighting device according to any one of claims 1 to 8 , wherein the light source unit has a light shielding portion between adjacent light sources.

Images