JPWO2015136848A1 - Inspection light source and inspection instrument equipped with the same - Google Patents

Abstract

The inspection light source 10 includes a substrate 11, a first electrode 12, a second electrode 14 paired with the first electrode 12, and an organic light emitting layer 13 disposed between the first electrode 12 and the second electrode 14. The planar light-emitting body 1 which has these. The organic light emitting layer 13 has a plurality of light emitting materials. The chromaticity of the irradiation light of the planar light-emitting body 1 is included in a region formed by connecting the centers of the MacAdam ellipses whose area is smaller than 5 × 10 −4 in the xy chromaticity diagram having a MacAdam ellipse magnified 10 times. It is.

Description

  The present invention relates to an inspection light source and an inspection instrument including the same. More specifically, the present invention relates to an inspection light source and an inspection instrument including a planar light emitter having an organic light emitting layer.

  2. Description of the Related Art Conventionally, there is known a light source in which irradiation light is adjusted so that a foreign object or the like can be easily found visually in product inspection or the like. For example, a sodium lamp generates monochromatic light, and defects can be detected by interference fringes. A light source with high color rendering properties (for example, Ra98) has been developed as a light source for visual inspection for contamination.

  It has also been proposed to use an organic electroluminescence element (hereinafter also referred to as “organic EL element”) as a light source for inspection. For example, Japanese Patent Publication No. 2006-507494 (hereinafter referred to as “Patent Document 1”) discloses a light source for a measuring apparatus using an organic EL element. Light sources using organic EL elements can be made thinner and lighter than conventional light sources. Therefore, the organic EL element can be an inspection light source excellent in handleability.

  In the inspection light source, it is important that a target inspection object such as a foreign object can be visually discriminated more clearly. However, the light source having the organic EL element disclosed in Patent Document 1 cannot be said to have sufficient visual discrimination.

  An object of the present invention is to provide an inspection light source and an inspection instrument having excellent visual discrimination.

An inspection light source according to the present disclosure includes a substrate, a first electrode, a second electrode paired with the first electrode, an organic light emitting layer disposed between the first electrode and the second electrode, The planar light-emitting body which has these. The organic light emitting layer has a plurality of light emitting materials. The chromaticity of the irradiation light of the planar light emitter is included in a region formed by connecting the centers of the MacAdam ellipses whose area is smaller than 5 × 10 ⁻⁴ in the xy chromaticity diagram having a MacAdam ellipse magnified 10 times. It is.

  An inspection instrument according to the present disclosure includes the above-described inspection light source and a housing.

  According to the present invention, the color difference is clarified by the irradiation light, so that the visual discrimination is improved.

It is an example of the chromaticity range of the irradiation light in a chromaticity diagram. FIG. 2 is composed of FIGS. 2A and 2B. FIG. 2A is a schematic diagram illustrating an example of an inspection light source. FIG. 2B is a partial enlarged cross-sectional view showing an example of a planar light emitter. FIG. 3 is composed of FIGS. 3A and 3B. FIG. 3A is a chromaticity diagram having a MacAdam ellipse. FIG. 3B is an explanatory diagram of a MacAdam ellipse. It is an example of the chromaticity range of the irradiation light in a chromaticity diagram. It is an example of the chromaticity range of the irradiation light in a chromaticity diagram. It is a chromaticity diagram having the center of a MacAdam ellipse. FIG. 7 is composed of FIGS. 7A to 7F. 7A to 7F are examples of the chromaticity range of the irradiation light in the chromaticity diagram. FIG. 8 is composed of FIGS. 8A to 8E. 8A to 8E are examples of chromaticity ranges of irradiation light in the chromaticity diagrams. FIG. 9 comprises FIG. 9A and FIG. 9B. FIG. 9A is an explanatory diagram showing an example of inspection using an inspection light source. FIG. 9B is an explanatory diagram illustrating an example of an inspection using an inspection light source. FIG. 10 includes FIG. 10A, FIG. 10B, and FIG. 10C. FIG. 10A is an explanatory diagram illustrating an example of an inspection using an inspection light source. FIG. 10B is an explanatory diagram illustrating an example of inspection using an inspection light source. FIG. 10C is an explanatory diagram illustrating an example of an inspection using an inspection light source. It is explanatory drawing which shows an example of the test | inspection using the light source for a test | inspection. It is a schematic diagram which shows an example of a test | inspection instrument.

The inspection light source of the present disclosure includes a planar light emitter 1 (see FIG. 2). The planar light emitter 1 includes a substrate 11, a first electrode 12, a second electrode 14 paired with the first electrode 12, and an organic light emitting layer disposed between the first electrode 12 and the second electrode 14. 13. The organic light emitting layer 13 has a plurality of light emitting materials. The chromaticity of the irradiation light of the planar light emitter 1 is included in a region formed by connecting the centers of the MacAdam ellipses having an area of 5 × 10 ⁻⁴ or less in the xy chromaticity diagram having a MacAdam ellipse of 10 times magnification. It is. In the inspection light source of the present disclosure, the color difference becomes clear depending on the irradiation light. As a result, visual discrimination is improved.

  FIG. 1 shows a range of irradiation light of the planar light emitter 1 in a chromaticity diagram having a MacAdam ellipse. The planar light emitter 1 has irradiation light of chromaticity in the area A1 shown in FIG.

  FIG. 2 shows an example of the inspection light source (inspection light source 10). FIG. 2 is composed of FIGS. 2A and 2B. FIG. 2A shows the overall configuration of the inspection light source 10. FIG. 2B shows an example of the planar light emitter 1 included in the inspection light source 10 of FIG. 2A. The inspection light source 10 has a planar light emitter 1. FIG. 2 is a schematic diagram, and the actual size of each part such as the thickness of the layer may be different from this figure. In FIG. 2A, the organic light emitting layer 13 inside the planar light emitter 1 is indicated by a broken line. A white arrow means a light emitting direction. FIG. 2B shows an enlarged view of a cross section of the planar light-emitting body 1.

  As illustrated in FIG. 2B, the planar light emitter 1 includes a substrate 11, a first electrode 12, an organic light emitting layer 13, and a second electrode 14. The planar light emitter 1 further has a sealing material 15. The planar light emitter 1 includes an organic electroluminescence element (organic EL element). The organic EL element is an element having a first electrode 12, an organic light emitting layer 13, and a second electrode 14, and capable of emitting light by current. The planar light emitter 1 may include an organic EL element and an electrical connection part. The electrical connection is arranged outside the sealing area. The electrical connection portion has a function of supplying electricity to the electrode of the organic EL element. The organic EL element forms a thin and light planar light emitter 1.

  When the planar light-emitting body 1 includes an organic EL element, highly uniform light can be efficiently obtained in a planar shape. When an LED that is not an organic EL element is used as a light source, since the LED is a point light source, it is required to planarize the light with a light guide plate, a diffusion plate, a scattering material, etc. in order to make the light emission uniform. . The light emitter with the planar LED of the point light source can be used as a light source for inspection. However, light emission loss occurs in various members or the light extraction efficiency decreases, resulting in light emission. Efficiency is extremely reduced. Therefore, an organic EL element is effective as a surface light source excellent in light emission uniformity. Further, there is an advantage that the light of the organic EL element is not easily shadowed.

  The substrate 11 can have a function of supporting each layer of the organic EL element. The substrate 11 can be a support substrate. Examples of the substrate 11 include a glass substrate and a resin substrate. The glass substrate can suppress intrusion of moisture and can improve sealing performance. The resin substrate preferably has an inorganic film. The inorganic film can suppress the intrusion of moisture and improve the sealing performance. The resin substrate can easily impart flexibility. The substrate 11 is preferably light transmissive. Light transmittance includes transparent and translucent.

  The first electrode 12 and the second electrode 14 are a pair of electrodes. One of these two electrodes is an anode and the other is a cathode. When electricity flows between the first electrode 12 and the second electrode 14, the organic light emitting layer 13 emits light. In the two electrodes, the wiring is preferably drawn outside the sealing region so that connection with a power source is possible. The first electrode 12 is defined as an electrode close to the substrate 11 of the two electrodes. At least one of the two electrodes is preferably light transmissive. Light transmittance includes transparent and translucent. The electrode having optical transparency can be an electrode on the light emitting surface side. The first electrode 12 is preferably light transmissive. Both of the two electrodes may have optical transparency. If both of the two electrodes have optical transparency, the planar luminous body 1 can be imparted with optical transparency. In one preferred embodiment, the first electrode 12 serves as an anode and the second electrode 14 serves as a cathode.

  The organic light emitting layer 13 is disposed between the first electrode 12 and the second electrode 14. The organic light emitting layer 13 has a function of generating light emission by the flow of electricity. The organic light emitting layer 13 has a layer containing a light emitting material (light emitting material containing layer). The luminescent material may be a so-called dopant. The organic light emitting layer 13 can be composed of a plurality of layers. The organic light emitting layer 13 preferably includes a layer for moving charges (charge transfer layer). The charge transfer layer can include a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer. In the case of a multi-unit structure, the charge transfer layer may include an intermediate layer.

  The layer configuration of the organic light emitting layer 13 is not particularly limited. FIG. 2B is an example of a layer configuration. In the example of FIG. 2B, the organic light emitting layer 13 includes a first charge transfer layer 31, a first light emitting material-containing layer 32, a second light emitting material containing layer 33, and a second charge transfer layer 34. The organic light emitting layer 13 can be composed of a plurality of layers containing an organic substance. Light is generated from the layer containing the light emitting material among the plurality of layers. For example, one or both of a hole transport layer and a hole injection layer are disposed on the anode side of the light emitting material-containing layer. For example, one or both of an electron transport layer and an electron injection layer are disposed on the cathode side of the light emitting material-containing layer. When the first electrode 12 is an anode and the second electrode 14 is a cathode, the first charge transfer layer 31 can include one or both of a hole injection layer and a hole transport layer, and the second charge transfer layer 34 is an electron transport layer. And one or both of the electron injection layer. Of course, it is not limited to the layer structure of FIG. 2B, For example, the organic light emitting layer 13 may have a multi-unit structure. The multi-unit structure has a plurality of light emitting units. In the multi-unit structure in which the layer configuration in FIG. 2B is modified, a charge transfer layer including an intermediate layer may be disposed between the first light emitting material-containing layer 32 and the second light emitting material containing layer 33.

  The organic light emitting layer 13 is usually sealed. The organic light emitting layer 13 is protected from the outside by sealing. In FIG. 2B, an example of a sealing structure is shown. In the example of FIG. 2B, the organic light emitting layer 13 is sealed by being disposed between the sealing material 15 and the substrate 11. The sealing material 15 can be made of a plate-like material. For example, the sealing material 15 can be composed of the same substrate as the substrate 11. The sealing material 15 can be composed of a sealing substrate. It is preferable that the sealing material 15 has light transmittance. Light transmittance includes transparent and translucent. The example of FIG. 2B has a gap 16 between the sealing material 15 and the second electrode 14. The gap 16 may be a cavity or a filler may be disposed.

  It is a preferable aspect that the planar light emitter 1 has a bottom emission structure. The bottom emission structure is a structure in which light is emitted from the support substrate. The planar light-emitting body 1 is another embodiment that preferably has a top emission structure. The top emission structure is a structure in which light is emitted from the side opposite to the support substrate. The planar light emitter 1 is another embodiment that preferably has a double-sided light emission structure.

  The inspection light source 10 in FIG. 2A includes a planar light emitter 1 and a power feeding circuit 2. Thus, the inspection light source 10 preferably includes the power feeding circuit 2 electrically connected to the planar light emitter 1. The power feeding circuit 2 in FIG. 2A includes a wiring 2A and an integrated unit 2B. The wiring 2 </ b> A is electrically connected to the electrode of the planar light emitter 1. Therefore, power can be supplied to the planar light emitter 1 through the wiring 2A. The integrated part 2B is a part in which the wiring 2A is integrated in order to facilitate power feeding. The integrated part 2B may have a terminal. The accumulation unit 2B may have a plug. The integrated unit 2B is connected to the wiring 4. The integrated unit 2 </ b> B is connected to the power source 3 through the wiring 4. Electricity from the power supply 3 flows to the planar light emitter 1 through the wiring.

  The power source 3 may be an external power source or an internal power source. An external power source means a power source connected via a wiring socket. The internal power supply means a power supply incorporated in the inspection light source 10. It is preferable that the inspection light source 10 includes an internal power source that supplies electricity to the planar light emitter 1 through the power feeding circuit 2. Thereby, the handleability of the inspection light source 10 is improved. Examples of the internal power source include a battery, a secondary battery, and a rechargeable battery. Further, the inspection light source 10 may be switchable between power supply from an external power supply and power supply from an internal power supply. In this case, when the power supply from the external power supply is stopped, such as during a power failure, the power supply can be switched to the power supply from the internal power supply, thereby improving the safety of the inspection. Of course, the inspection light source 10 may not have an internal power source.

  In FIG. 2A, light is emitted from the substrate 11 side. The light emitted from the inspection light source 10 is irradiated to the inspection object. The light irradiated toward the object can be reflected, absorbed and transmitted when it reaches the object. And the target object illuminated by irradiation light emits a color. Inspection is performed by visually judging this color. And in the inspection light source of this indication, color judgment becomes easy because chromaticity of irradiation light enters in a specific field in a chromaticity diagram.

  FIG. 3A shows a chromaticity diagram with a MacAdam ellipse. FIG. 3B shows an explanatory diagram of the MacAdam ellipse. FIG. 3 is composed of FIGS. 3A and 3B. In general, a chromaticity diagram is often displayed in color, but in this chromaticity diagram, colors are omitted. This chromaticity diagram is a CIE-XYZ display system. This chromaticity diagram is called an xy chromaticity diagram. Chromaticity diagrams are well known in the technical field of color space, and even if colors are omitted, the arrangement of colors will be easily understood. In the chromaticity diagrams shown in the subsequent figures, colors are also omitted. The chromaticity diagram represents an xy chromaticity diagram unless otherwise specified.

  FIG. 3A shows the arrangement of Mac Adam ellipses (Mac Adam ellipses) in the xy chromaticity diagram. The chromaticity diagram of FIG. 3A is an xy chromaticity diagram of CIE1931. In the chromaticity diagram, colors are two-dimensionally represented by x and y values. The chromaticity of the irradiation light is also defined by the x value and the y value. x and y constitute chromaticity coordinates. The color range represented by the chromaticity diagram is a range surrounded by a thick line in FIG. 3A. This range has a rounded triangular shape in which two sides extending upward are curved with the left side inclined upward and projecting upward. In the chromaticity diagram, green becomes darker as the chromaticity coordinate is higher, blue becomes darker as it goes to the lower left, and red becomes darker as it goes to the lower right. The numbers from 450 to 650 written along this curve in the vicinity of the curve are the wavelengths of light. The unit of the wavelength of light is nm. White is arranged slightly to the right near the center of the triangle (near ME13). FIG. 3A shows a McAdam ellipse magnified 10 times. Such a McAdam ellipse enlarged 10 times is also well known.

  The MacAdam ellipse is derived from a visual color matching experiment, and represents the standard deviation of the identification variation with respect to a specific central color in an xy chromaticity diagram. The MacAdam ellipse was proposed by Mac Adam. As shown in FIG. 3A, there are 25 McAdam ellipses. When comparing the color of the center of the McAdam ellipse with other colors, if the other colors are within the same range of the same McAdam ellipse, they feel the same color ergonomically. That is, the colors within the range of the MacAdam ellipse feel the same color, so it is difficult to distinguish the colors. It can be said that the MacAdam ellipse is a representative example of the color matching range. Here, as can be seen from FIG. 3A, the MacAdam ellipses in the chromaticity diagram have unequal sizes. Above the chromaticity diagram, the MacAdam ellipse is large, and even if the chromaticity coordinates are different, it is difficult to make a difference in color. On the other hand, in the lower left of the chromaticity diagram, the MacAdam ellipse is small and can be identified by a slight difference in chromaticity coordinates. The color-matching property of the MacAdam ellipse is considered to show the same tendency in chromaticity coordinates other than the center of the MacAdam ellipse. That is, it is considered that the equal color range is large above the chromaticity diagram and the uniform color range is small below the chromaticity diagram. Therefore, if a color (first color) and another color (second color) are compared, if the two chromaticity coordinates are in a relationship that causes loss of color matching, then the color is discriminated. Becomes easier. The inspection light source of the present disclosure focuses on this point.

  The object illuminated by the irradiation light from the inspection light source produces a color due to the color of the irradiation light. The color is confirmed visually. Here, the target object may include a main body part that is a main body of the target object and an identification unit that is desired to be identified as being different from the main body part. For example, when the object is a resin molded product and the purpose of the inspection is to find a foreign object in the resin molded product, the main body portion is the entire resin molded product and the identification unit is a foreign material. When the object is irradiated with light from the inspection light source, if the difference between the color of the main body (first color) and the color of the identification part (second color) is felt to be large, the color is easily distinguished. This can improve the discriminability with respect to the discriminating part (foreign matter). Light in a region having a small color matching range is advantageous for improving discrimination.

  In FIG. 3A, the McAdam ellipse is displayed as ME, followed by a number. There are 25 MacAdam ellipses from ME00 to ME24. The center of the MacAdam ellipse corresponds to the ME number and is numbered C00-C24, respectively. FIG. 6 is a chromaticity diagram having the center of a MacAdam ellipse. From this chromaticity diagram, the arrangement of the center of the MacAdam ellipse is understood. C00 to C24 mean chromaticity coordinates.

Table 1 shows the numerical values of the elements of the MacAdam ellipse ME based on the numbering of FIG. 3A. In Table 1, in each MacAdam ellipses, chromaticity coordinates of the center (x, y), the length of half the length axis R _a, half of the minor axis length R _b, the angle between the x axis and the long axis θ The area is shown. This area is the area of the MacAdam ellipse after the original MacAdam ellipse proposed by McAdam has been magnified 10 times. That is, this area is based on the size of the MacAdam ellipse shown in FIG. 3A. The unit of the angle θ is degrees. FIG. 3B shows R _a , R _b and θ in the MacAdam ellipse. The area of the ellipse is π × R _a × R _b from the formula. π is the circumference ratio. Regions A1 to A3 in the table correspond to the region numbers described below, and mean the attribution of the MacAdam ellipse that forms each region.

In the inspection light source of the present disclosure, the chromaticity of the irradiation light of the planar light emitter 1 connects the centers of the MacAdam ellipses whose area is smaller than 5 × 10 ⁻⁴ in the xy chromaticity diagram having the MacAdam ellipse that is 10 times larger. It is included in the region formed by. The center is connected by a straight line. FIG. 1 shows this chromaticity region as A1. A region A1 is a hatched portion in FIG. In the area A1, the color matching range is relatively small. Therefore, it becomes easy to distinguish the color difference.

The area A1 shown in FIG. 1 will be described with reference to Table 1 as follows. There are 13 McAdam ellipses with an area smaller than 5 × 10 ⁻⁴ , ME00, ME01, ME02, ME10, ME11, ME12, ME16, ME17, ME19, ME20, ME21, ME22, and ME23. Connect the centers of these ellipses with a straight line. Then, the straight line passing through the inside of the region A1 is ignored, and the outer edge of the region A1 is formed as a straight line. The region A1 is a range surrounded by straight lines connecting the centers of the MacAdam ellipses of ME00, ME10, ME11, ME12, ME16, ME17, ME21, ME23, ME02, and ME00 in this order. As can be seen from FIG. 6, the area A1 is a range surrounded by a straight line connecting the chromaticity coordinates C00, C10, C11, C12, C16, C17, C21, C23, C02, and C00 in this order at the center of the MacAdam ellipse. It may be said. Here, from Table 1, for example, the chromaticity coordinate C00 can be expressed as (0.160, 0.057), and the chromaticity coordinate C21 can be expressed as (0.441, 0.198). Other chromaticity coordinates can be similarly expressed. Therefore, the area A1 can be expressed by numerical values of these chromaticity coordinates. In the following, the same definition method as this explanation is applied to the region formed by connecting the centers of the MacAdam ellipses.

  When the chromaticity of the irradiation light from the planar light emitter is in the area A1, the color (first color) of the main body part of the object and the identification part are compared with those in the case where the chromaticity of the irradiation light is outside the area A1 The difference in color from the color (second color) becomes clear. This is because the area A1 has a small equal color range. This facilitates visual inspection and improves inspection. Moreover, even if the object is difficult to understand, such as a foreign object in light and dark, it is easy to inspect by using the color difference. Moreover, since the difference in the spectrum of reflected light appears as a color, the inspection accuracy is improved. In addition, the color difference becomes clear as compared with the light source of white light or monochromatic light used in the conventional inspection. In the chromaticity diagram, there may be chromaticity coordinates having a narrower color matching range than the area A1, but the area A1 has the chromaticity of the irradiation light of the planar light emitter 1 arranged in that area. There is an advantage that it is easy. Therefore, it is effective to select the region A1 as the chromaticity range of the irradiation light.

  The area A1 may not include a white area. From the MacAdam ellipse in FIG. 3A, it can be seen that the white region has a relatively large color matching range. The white region in the chromaticity diagram is roughly arranged around the left side of the center (chromaticity coordinates C13) of the MacAdam ellipse ME13. If the chromaticity of the irradiation light is located at a place where the color matching range is large, even if a difference occurs in the reflected light, it is difficult to visually distinguish. Note that the chromaticity coordinate C12, which is the center of the MacAdam ellipse ME12, is disposed near the white region, but the light of the chromaticity coordinate C12 is difficult to feel white when confirmed by human eyes. In this specification, it is defined that the light at the chromaticity coordinate C12 is not white. White is defined as a color temperature of 3000K to 7000K. The color temperature of white is preferably 3500K or higher, more preferably 4000K or higher, and further preferably 4500K or higher. White preferably has a color temperature of 6500K or less, more preferably 6000K or less, and even more preferably 5500K or less.

  The light emission of the planar light emitter 1 may be multicolor light. Multicolor light is produced by combining light emission of different colors. In an inspection using monochromatic light, since the color does not change, a change in luminance (brightness) is determined, and an inspection using a difference in color is usually not possible. On the other hand, with multi-color light, it is possible to inspect using a difference in color.

  Here, the organic light emitting layer 13 has at least two light emitting materials. When there is one luminescent material, the chromaticity of the emitted light emitted from the planar light emitter 1 is arranged at the outer edge of the triangular chromaticity range (near the position where the wavelength scale is marked) in the chromaticity diagram of FIG. 3A. Easy to be. For this reason, with a single light-emitting material, the chromaticity of the irradiated light is less likely to enter the region A1 in FIG. 1, and the color discrimination may be reduced. However, when there are multiple light emitting materials, the color of light emitted from the light emitting materials is mixed to create an overall color, and the chromaticity of the irradiated light is lower than the center part of the chromaticity diagram. It becomes easy to arrange | position to A1. For this reason, the use of a plurality of light emitting materials improves visual discrimination. When there is one luminescent material, the irradiation light is monochromatic light. When there are two or more luminescent materials, the irradiation light becomes multicolor light.

  At least one of the plurality of light emitting materials is preferably a blue light emitting material. When a blue light emitting material is used, the chromaticity of the irradiation light is likely to be located on the lower left side of the chromaticity diagram (see FIG. 3A). For this reason, the chromaticity of the irradiated light easily enters the region A1. Further, the lower left portion of the chromaticity diagram has a relatively small color matching range, as can be seen from the small size of the MacAdam ellipse. For this reason, the visual discrimination by the inspection light source is further improved. The blue light emitting material may have an emission wavelength peak in a range larger than 400 nm and smaller than 495 nm.

  The peak of the emission wavelength of the blue light emitting material is preferably smaller than 490 nm, more preferably smaller than 480 nm, still more preferably smaller than 470 nm, and still more preferably smaller than 460 nm. When the blue light emitting material has a shorter wavelength, the chromaticity of the irradiation light of the planar light emitter 1 is easily arranged in the region A1.

  The plurality of light emitting materials may include a red light emitting material. When a red light emitting material is used, the chromaticity of the irradiated light is affected toward the lower right of the chromaticity diagram. Below the chromaticity diagram, the size of the MacAdam ellipse is smaller than above (see FIG. 3A). Therefore, the visual discrimination can be improved.

  In one preferred embodiment, the plurality of light emitting materials include a blue light emitting material and a red light emitting material. In the chromaticity diagram, the blue light emitting material has an action toward the lower left, and the red light emitting material has an action toward the lower right. Then, as shown in FIG. 3A, the chromaticity of the irradiation light is likely to be located near the lower side of the center of the chromaticity diagram, and more easily enters the region A1. The plurality of light emitting materials may include a plurality of different types of blue light emitting materials or a plurality of different types of red light emitting materials.

  The plurality of light emitting materials may include light emitting materials of colors other than blue and red. Examples of such a light emitting material include a green light emitting material, a yellow light emitting material, and an orange light emitting material. However, these luminescent materials may have an action toward the upper side of the chromaticity diagram. In order to keep the chromaticity of the irradiation light within the area A1, it is preferable to reduce the intensity of the light emitting material other than blue and red. The plurality of light emitting materials may not include a green light emitting material, a yellow light emitting material, and an orange light emitting material.

  In a plurality of light emitting materials, chromaticity can be adjusted by adjusting the intensity ratio thereof. The chromaticity coordinates of the irradiation light in the chromaticity diagram can be determined by the emission wavelength of each luminescent material in a single color and the intensity ratio thereof. For example, when a blue light emitting material having an emission wavelength of about 460 nm and a red light emitting material having an emission wavelength of about 600 nm are used, the chromaticity of the irradiated light is a straight line connecting “460” and “600” at the outer edge of the chromaticity diagram. Therefore, it becomes easy to enter the region A1.

  The luminescent material is disposed in the luminescent material-containing layer. The plurality of light emitting materials may be all arranged in one light emitting material-containing layer, or may be divided into a plurality of light emitting material containing layers. In one preferred embodiment, one light emitting material-containing layer has one light emitting material. FIG. 2B shows an example in which two luminescent material-containing layers exist, and these two luminescent material-containing layers can have different luminescent materials. For example, the plurality of light emitting material-containing layers may have a structure in which the first light emitting material containing layer 32 contains a blue light emitting material and the second light emitting material containing layer 33 contains a red light emitting material. Different luminescent materials are arranged in the respective luminescent material-containing layers, so that the chromaticity of the irradiated light easily enters the region A1.

  FIG. 4 shows a region A2. In the MacAdam ellipse that forms the chromaticity region of the irradiation light, it is preferable that the angle θ between the major axis of the MacAdam ellipse and the x axis of the xy chromaticity diagram is larger than 0 degree and smaller than 90 degrees. is there. A region A2 indicates the chromaticity range of this aspect. In this embodiment, the color difference can be clearer. In the inspection of an object, if a color difference occurs in the direction of the short axis of the MacAdam ellipse, the color difference is more easily felt. This is because the color matching range is narrow in the direction along the short axis of the MacAdam ellipse. As can be seen from FIG. 3B, in this aspect, the MacAdam ellipse has a shape extending from the lower left to the upper right. Here, in the range where the angle θ is larger than 0 degree and smaller than 90 degrees, the sensitivity of green strength becomes high. Since green has high visual sensitivity, the intensity of green is perceived sensitively by humans. Therefore, it is easy to determine the color. In addition, when the object to be inspected has a green color, visual discrimination can be improved. Here, when the angle θ is larger than 0 degree and smaller than 45 degrees, it becomes sensitive to the color difference in the green and red regions. This is because the minor axis of the ellipse is close to the direction along the y-axis. Further, when the angle θ is larger than 45 degrees and smaller than 90 degrees, it becomes sensitive to the color difference in the blue and green regions. This is because the minor axis of the ellipse is close to the direction along the x axis. As a result, the inspection performance is improved in the range where the angle θ is larger than 0 degree and smaller than 90 degrees.

  Region A2 in FIG. 4 is formed by connecting the centers of the MacAdam ellipses whose angle θ between the major axis of the ellipse and the x-axis is greater than 0 degree and smaller than 90 degrees among the MacAdam ellipses constituting area A1. . The method for forming the region is the same as that for the region A1. From Table 1, the MacAdam ellipses whose angle θ is larger than 0 degree and smaller than 90 degrees are ME00, ME01, ME02, ME11, ME12, ME16, ME17, ME19, ME20, ME21, ME22, and ME23. From these McAdam ellipses, a region A2 is derived.

  FIG. 5 shows a region A3. In the MacAdam ellipse that forms the chromaticity region of the irradiation light, an angle θ between the major axis of the MacAdam ellipse and the x axis of the xy chromaticity diagram is preferably greater than 70 degrees and smaller than 120 degrees. is there. A region A3 indicates the chromaticity range of this aspect. In this embodiment, the color difference can be clearer. As can be seen from FIG. 3B, in this embodiment, the MacAdam ellipse has a shape that extends upward from below. Here, in the range where the angle θ is larger than 70 degrees and smaller than 120 degrees, the sensitivity of red and blue is high. This is because the minor axis of the ellipse is close to the direction along the x axis. Depending on the color of the object, red is difficult to distinguish or blue is difficult to distinguish. In such a case, it is easier to judge the color. Further, when the inspection object has one or both of blue and red, the visual discrimination can be improved particularly.

  The area A3 in FIG. 5 is formed by connecting the centers of the MacAdam ellipses whose angle θ between the major axis of the ellipse and the x-axis is greater than 70 degrees and smaller than 120 degrees among the MacAdam ellipses constituting the area A1. . The method for forming the region is the same as that for the region A1. From Table 1, the MacAdam ellipses whose angle θ is larger than 70 degrees and smaller than 120 degrees are ME01, ME10, and ME11. From these McAdam ellipses, a region A3 is derived.

  FIG. 6 shows the arrangement of the centers C of the MacAdam ellipses in the chromaticity diagram. By extracting only the center of the MacAdam ellipse from the chromaticity diagram of FIG. 3, the layout diagram of FIG. 6 is derived. Below, in order to simplify description, it demonstrates based on this chromaticity diagram.

  Table 2 shows the relationship between the MacAdam ellipse and its center number and the areas A4 to A14 described below. The MacAdam ellipse is extracted from the area A1. From this table, the relationship between each region and the MacAdam ellipse will be easily understood.

  FIG. 7 is an example of each chromaticity range of the irradiation light of the planar light emitter in the chromaticity diagram. FIG. 7 includes FIGS. 7A to 7F. In FIG. 7A to FIG. 7F, preferred embodiments of the chromaticity range of the irradiation light are shown. These chromaticity ranges are all present in the area A1.

FIG. 7A shows a region A4. The region A4 is formed by connecting the centers of the MacAdam ellipses whose area is smaller than 4.5 × 10 ⁻⁴ . FIG. 7B shows a region A5. The region A5 is formed by connecting the centers of the MacAdam ellipses whose area is smaller than 4.4 × 10 ⁻⁴ . FIG. 7C shows a region A6. The region A6 is formed by connecting the centers of MacAdam ellipses having an area smaller than 4.2 × 10 ⁻⁴ . FIG. 7D shows a region A7. The region A7 is formed by connecting the centers of the MacAdam ellipses whose area is smaller than 4 × 10 ⁻⁴ . FIG. 7E shows a region A8. The region A8 is formed by connecting the centers of MacAdam ellipses whose area is smaller than 3.8 × 10 ⁻⁴ . FIG. 7F shows a region A9. The region A9 is formed by connecting the centers of MacAdam ellipses whose area is smaller than 3.1 × 10 ⁻⁴ . As the area of the MacAdam ellipse becomes smaller, the color matching range tends to become smaller, and the inspection property can be improved. Therefore, the region where the chromaticity of the irradiation light of the planar light emitter 1 enters becomes more preferable in the order of the regions A4, A5, A6, A7, A8, and A9.

  FIG. 8 is an example of each chromaticity range of the irradiation light of the planar light emitter in the chromaticity diagram. FIG. 8 includes FIGS. 8A to 8E. 8A to 8E show preferable modes of the chromaticity range of the irradiation light. These chromaticity ranges are all present in the area A1.

  FIG. 8A shows a region A10. The area A10 is formed by connecting the centers of the MacAdam ellipses in which the angle θ between the major axis of the ellipse forming the area A1 and the x axis of the xy chromaticity diagram is greater than 0 degree and less than 45 degrees. The When the angle θ is in the range of 0 degrees to 45 degrees, it becomes sensitive to the color difference in the green and red regions. For this reason, the region A10 is effective when the reflected light from the object changes from green to red.

  FIG. 8B shows a region A11. The area A11 is formed by connecting the centers of the MacAdam ellipses whose angle θ between the major axis of the ellipse forming the area A1 and the x axis of the xy chromaticity diagram is greater than 45 degrees and smaller than 90 degrees. The When the angle θ is in the range of 45 degrees to 90 degrees, it becomes sensitive to the color difference in the blue and green regions. Therefore, the region A11 is effective when the reflected light from the object is a blue to green region.

FIG. 8C shows a region A12. In the area A12, among the MacAdam ellipses forming the area A1, the angle θ between the major axis of the ellipse and the x axis of the xy chromaticity diagram is larger than 45 degrees and smaller than 90 degrees, and the area is 4 × 10 ^−. It is formed by connecting the centers of MacAdam ellipses smaller than ⁴ . The area A12 satisfies the condition of the area A7 in FIG. 7D and the condition of the area A11 in FIG. 8B at the same time. As described above, the chromaticity range of the irradiation light may be optimized in consideration of both the angle θ and the area of the MacAdam ellipse. Thereby, the testability can be improved.

  FIG. 8D shows a region A13. Region A13 is a suitable region A7 in FIG. 7D. In the inspection light source, it is a preferable aspect that the irradiation light of the planar light emitter is far from the white region. In the case of an organic EL element that emits white light, the chromaticity of the irradiation light is roughly circular in the chromaticity diagram from the right side of the chromaticity coordinate C12 to the left side of the chromaticity coordinate C14 with the chromaticity coordinate C13 as the center. Can be in the region extending to Here, when the chromaticity of the light emitted from the planar light emitter is close to the chromaticity coordinate C12, the light emitted from the planar light emitter tends to be close to white. Therefore, it is preferable not to include the vicinity of the chromaticity coordinates C12. This idea leads to a region A13 excluding the MacAdam ellipse ME12 centered on the chromaticity coordinates C12 among the MacAdam ellipses forming the region A7.

FIG. 8E shows a region A14. The region A14 is formed by connecting the centers of the MacAdam ellipses having an area larger than 1 × 10 ⁻⁴ among the MacAdam ellipses forming the region A1. The smaller the area of the MacAdam ellipse, the better. Therefore, the lower limit of the area of the MacAdam ellipse need not be set. However, the lower limit of the area of the MacAdam ellipse may be set. Region A14 in FIG. 8E shows an example in which the lower limit of the area of the MacAdam ellipse is set.

  FIG. 9 shows an example of each inspection using the inspection light source 10. FIG. 9 comprises FIG. 9A and FIG. 9B. A white arrow indicates light generated from the inspection light source 10. In FIG. 9, the planar light emitter 1 is extracted from the inspection light source 10 and displayed, and other members are omitted. The light emitted from the inspection light source 10 is applied to the inspection object 9. The planar light emitter 1 has a front surface 1a and a rear surface 1b. The front surface 1a is a surface that emits light toward the inspection object 9, and serves as a light emitting surface. The rear surface 1b is a surface on the opposite side to the front surface 1a and is the back surface.

  In FIG. 9A, the inspection light source 10 has a planar planar light emitter 1. 9A does not have a curved surface. The planar planar light emitter 1 is suitable when the surface of the inspection object 9 is a flat surface. On the other hand, in FIG. 9B, the inspection light source 10 includes the planar light emitter 1 having a curved portion. The light emitting surface of the planar light emitter 1 in FIG. 9B has a curved surface. As shown in FIG. 9B, the planar light-emitting body 1 is a preferable embodiment in which the light-emitting surface includes a curved surface. The planar light emitter 1 whose light emitting surface includes a curved surface is suitable when the inspection object 9 has a curved surface. In this case, light is more uniformly irradiated to the inspection object 9. Further, when the light emitting surface is a curved surface, the amount of irradiation light directed toward the inspection object 9 is increased. Therefore, the color discrimination is improved. The planar light emitter 1 may be bent in an arc shape. The planar light emitter 1 may be bent in a bow shape. Regardless of the presence or absence of a curved portion, the light from the planar light-emitting body 1 is preferably more uniform, and the color is more uniform and the luminance is more uniform in the plane. Moreover, it is preferable that the planar light-emitting body 1 has less angle dependency of irradiation light. Angle dependency means that the color looks different depending on the viewing angle.

  The planar light-emitting body 1 having a bent portion may be permanently maintained in a bent state, or may be deformed between a bent state and a non-bent state (flat state). . The planar light-emitting body 1 which has a permanent curved part does not need to bend any more. In this case, the intensity | strength of the planar light-emitting body 1 increases. On the other hand, the planar light-emitting body 1 that can be deformed with or without a curved portion can switch the presence or absence of a curved portion according to the state of inspection, so that the inspection performance is improved. In the planar light-emitting body 1 having a deformable curved portion, a bent state can be maintained at the time of inspection. It is preferable that the planar light-emitting body 1 which has a deformable curved part can change the bending degree. Thereby, the testability is further improved. For example, in the planar light-emitting body 1 that bends in an arc shape, the degree of bending can be changed by changing the radius of curvature. In this case, the planar light-emitting body 1 can be maintained in a bent state at each bending degree at the time of inspection. In addition, the planar light-emitting body 1 which has a deformable curved part may change a bending degree within the range of the bent state, without deform | transforming into a flat state.

  When the planar light emitter 1 has a curved portion, the substrate of the planar light emitter 1 (substrate 11 in FIG. 2B) is preferably a flexible substrate. The flexible substrate can easily make the light emitting surface curved. A flexible substrate is a substrate that has bendability and the degree of bend can be changed. The flexible substrate can be flat. In the flexible substrate, an electrode and an organic light emitting layer may be formed on the flexible substrate in a flat state. Moreover, it is preferable that the sealing material (planar material 15 of FIG. 2B) of the planar light-emitting body 1 has flexibility. For example, when the sealing material is constituted by a substrate, the sealing material is preferably a flexible substrate. After joining a flexible substrate (support substrate) and another flexible substrate (sealing material) and sealing the organic light emitting layer, these can be bent. Each layer of the planar light emitter 1 is preferably configured so as not to break when the planar light emitter 1 is bent.

  When the inspection light source 10 includes the planar light emitter 1 having a curved portion, the inspection light source 10 preferably includes a curved portion holding material that maintains the curved portion of the planar light emitter 1. By holding the curved portion of the planar light emitter 1, a stable inspection can be performed. FIG. 9B illustrates a curved portion holding material 8 that holds the both ends of the planar light-emitting body 1 so that the planar light-emitting body 1 is held and held in that state. The curved portion holding member 8 may be configured such that the degree of bending of the planar light emitter 1 can be changed. The curved portion holding material is not limited to this mode. For example, the curved portion holding material may be configured by a member having a curved portion disposed on the surface of the planar light-emitting body 1. Also in this case, it is preferable that the bending degree holding material can change the degree of bending.

  In FIG. 9, the direction in which the inspection object 9 is viewed is indicated by broken arrows HE1 and HE2. The inspection object 9 irradiated with light is confirmed by human eyes. When the planar light emitter 1 does not have light transmittance, the inspection object 9 cannot be confirmed from the rear surface 1 b of the planar light emitter 1. Therefore, the inspection object 9 is visually confirmed from a direction that does not pass the planar light emitter 1, such as the direction of the arrow HE1.

  Here, it is a preferable aspect that the planar light-emitting body 1 has light transmittance in a direction perpendicular to the surface of the substrate (the same direction as the arrow HE2 in FIG. 9). In this case, the inspection object 9 can be confirmed from the rear surface 1b side of the planar light emitter 1. Light transmittance includes transparent and translucent. The planar light emitter 1 is preferably transparent. The light transmittance of the planar light-emitting body 1 may be exhibited as long as the first electrode 12, the organic light-emitting layer 13, and the second electrode 14 exist in the thickness direction. The edge part of the planar light-emitting body 1 does not need to have a light transmittance. The planar light-emitting body 1 preferably has light transmittance in a range including a range where light emission occurs. As shown by an arrow HE1 in FIG. 9, when the inspection object 9 is confirmed while avoiding the planar light emitter 1, the inspection object 9 is confirmed from an oblique direction, or the light of the planar light emitter 1 is obliquely observed. It is required to irradiate the inspection object 9 from the direction. Therefore, it is difficult to visually recognize the light reflected in the direction opposite to the light directed toward the inspection object 9. Further, the light reflected by the inspection object 9 may have angle dependency. In that case, it may be difficult to distinguish the color difference depending on the viewing angle. Although it is conceivable to increase the distance between the inspection object 9 and the planar light emitter 1 so that the inspection object 9 is easily visible, in that case, the amount of light hitting the inspection object 9 may be reduced and the sensitivity may decrease. is there.

  On the other hand, when the planar light emitter 1 is light transmissive, the light reflected by the inspection object 9 passes through the planar light emitter 1 and travels behind the planar light emitter 1. Therefore, it is possible to visually confirm the inspection object 9 from the direction of the arrow HE2. As a result, it becomes easy to visually recognize the inspection object 9 and the inspection becomes easy. Further, since the angle dependency of the reflected light can be reduced, the visual discrimination is improved. Further, when the inspection object 9 is confirmed from the direction of the arrow HE2, since the light reflected in the opposite direction on the inspection object 9 can be directly confirmed, the inspection sensitivity is easily improved. Moreover, since the planar light-emitting body 1 can be easily disposed near the inspection object 9, the inspection object 9 can be inspected from a close distance. Furthermore, since inspection can be performed in a state where the inspection object 9 and the planar light emitter 1 are in contact with each other, the inspection accuracy is further improved. If inspection from a close distance becomes possible, it becomes possible to inspect with a light source with a smaller amount of light. Therefore, energy efficiency can be improved (energy saving).

  When the planar light emitter 1 is light transmissive, the light of the planar light emitter 1 can be irradiated not only from the front surface 1a but also from the rear surface 1b. The transparent planar light emitter 1 can have a double-sided light emitting structure. At this time, it is preferable that the irradiation light in the direction of the inspection object 9 in the planar light emitter 1 is stronger than the light in the direction opposite to the inspection object 9. It may be said that the light from the front surface 1a is stronger than the light from the rear surface 1b. In the double-sided light emission structure, the intensity of light may be different between one surface and the other surface. At that time, the intensity of the irradiation light from the front surface 1a, which is the light toward the inspection object 9, becomes stronger than the light from the rear surface 1b in the opposite direction, so that the inspection object 9 is irradiated with more light. can do. Further, when the light from the rear surface 1b becomes weaker than the light from the front surface 1a, the light directed directly rearward from the planar light emitter 1 does not easily interfere with the inspection, and the inspection object from the rear of the planar light emitter 1 The visibility of 9 is improved. Therefore, the accuracy of the inspection is increased.

  FIG. 10 is an explanatory diagram illustrating an example of inspection using an inspection light source. FIG. 10 includes FIG. 10A, FIG. 10B, and FIG. 10C. As shown in FIG. 10, the inspection light source 10 is preferably provided with an additional light emitter 5 having irradiation light with a chromaticity different from that of the planar light emitter 1. The additional light emitter 5 is a light emitter provided in addition to the planar light emitter 1. The additional light emitter 5 can be configured to be driven independently of the planar light emitter 1. When the inspection light source 10 includes the additional light emitter 5, the light applied to the inspection object 9 may change. Therefore, inspection can be performed with light of different chromaticities, and inspection performance is improved. In FIG. 10, the irradiation light of the additional light emitter 5 is indicated by a dashed white arrow. Although the planar light emitter 1 having a curved portion is illustrated in FIG. 10, the additional light emitter 5 can be installed even in the planar light emitter 1 having no curved portion.

  FIG. 10A is an example in which the additional light emitter 5 and the planar light emitter 1 are arranged in parallel. In this example, irradiation light from both the planar light emitter 1 and the additional light emitter 5 directly reaches the inspection object 9. Therefore, the chromaticity of the irradiation light is stabilized and the overall intensity of the irradiation light is increased, so that the inspection property can be improved. In FIG. 10A and FIG. 10B, the additional light emitter 5 is composed of a lamp. The lamp is preferably monochromatic.

  FIG. 10B is an example in which the additional light emitter 5 and the planar light emitter 1 are arranged in series. The additional light emitter 5 is disposed behind the planar light emitter 1. The planar light emitter 1 is light transmissive. In this example, the irradiation light of the additional light emitter 5 passes through the planar light emitter 1 and reaches the inspection object 9. In this example, since the light emitting surface of the planar light emitter 1 can be made larger, the inspection property can be improved.

  FIG. 10C is an example in which the additional light emitter 5 is configured by the additional planar light emitter 5A. The additional planar light emitter 5A may have an organic EL element or a structure in which a point light source LED is planarized. The additional planar light emitter 5A preferably has an organic EL element. Thereby, the planar additional light emitter 5 having high light emission efficiency and excellent light emission uniformity can be obtained. The reason why the organic EL element is preferable to the point light source LED is the same as described above. The additional planar light emitter 5A can have the same configuration as the planar light emitter 1 except that the chromaticity of the irradiation light is different. However, the additional planar light emitter 5A may include one light emitting material. The additional planar light emitter 5A may have monochromatic light. Although FIG. 10C shows an example in which the planar light emitter 1 and the additional planar light emitter 5A are arranged in parallel, they may be arranged in series (front-rear direction).

  As shown in FIG. 10, when the inspection light source 10 includes the additional light emitter 5, it is preferable to include a light intensity variable unit 6 that changes the intensity of the irradiation light of the additional light emitter 5. When the light intensity of the additional light emitter 5 is variable, the inspection property is improved.

  An example of a change in intensity of the additional light emitter 5 by the light intensity variable unit 6 is the presence or absence of light emission. In this aspect, the inspection light source 10 can be switched between a state in which both the planar light emitter 1 and the additional light emitter 5 emit light and a state in which the planar light emitter 1 emits light and the additional light emitter 5 does not emit light. Configured. The inspection light source 10 may be further switchable to a state in which the planar light emitter 1 does not emit light and the additional light emitter 5 emits light. The inspection light source 10 may be configured such that power can be separately supplied to the planar light emitter 1 and the additional light emitter 5. The inspection light source 10 may have a state in which neither the planar light emitter 1 nor the additional light emitter 5 emits light.

  It is preferable that the light intensity variable unit 6 changes the light intensity within a range in which the additional light emitter 5 emits light. In that case, the light intensity variable unit 6 can emit strong light and weak light from the additional light emitter 5. Thereby, inspection with irradiation light of a plurality of chromaticities becomes possible, and the inspection performance is further improved. The change in intensity may be stepwise or continuous.

  10A and 10B, the light intensity variable unit 6 is electrically connected to the additional light emitter 5. The light intensity variable unit 6 can be configured by a current control circuit capable of controlling the amount of current. The light intensity variable unit 6 can change the intensity of the irradiation light of the additional light emitter 5 by increasing or decreasing the amount of current to the additional light emitter 5. In FIG. 10C, the light intensity variable unit 6 is configured by a slide that allows the distance between the additional planar light emitter 5 </ b> A and the inspection object 9 to be changed. The light intensity variable unit 6 can change the intensity of irradiation light of the additional light emitter 5 by moving the additional light emitter 5 close to or away from the inspection object 9. In addition, the structure of the light intensity variable part 6 is not restricted to what is shown in FIG. The light intensity variable unit 6 may be configured by, for example, one or a plurality of filters that can adjust the light intensity by blocking light. Further, the inspection light source 10 may be configured such that the light intensity of the planar light emitter 1 can be changed. In short, when the intensity ratio of light between the planar light-emitting body 1 and the additional light-emitting body 5 can be changed, the chromaticity of the entire irradiation light can be changed, so that the inspection property is improved.

  The emission color of the additional light emitter 5 is preferably red or blue. As a result, the entire irradiation light easily enters the area A1, and the inspection performance is improved. It is preferable that the chromaticity of the irradiation light (irradiation light of the inspection light source 10) obtained by combining the two light emissions of the planar light emitter 1 and the additional light emitter 5 falls within the area A1. The chromaticity of the irradiation light of the additional light emitter 5 may not be in the region A1, or may be in the region A1. The irradiation light of the additional light emitter 5 is preferably red monochromatic light or blue monochromatic light. The chromaticity of the irradiation light of the inspection light source 10 is preferably changed in the region A1 due to the intensity change of the additional light emitter 5. Thereby, an inspection can be performed with a plurality of chromaticities.

  The emission color of the additional light emitter 5 may be selected from green, yellow, and orange. In that case, the chromaticity may be outside the region A1 in a state where two light emitters emit light, and the chromaticity may be in the region A1 in a state where only the planar light emitter 1 emits light. In this aspect, white light can be irradiated when the two light emitters emit light. For example, preliminary confirmation can be performed with white light, and the main inspection can be performed with irradiation light only from the planar light emitter 1.

  The inspection object 9 may have a plurality of types of light reflection spectra. In that case, the aspect which has the additional light-emitting body 5 is suitable. This aspect is also effective when inspecting different types of inspection objects 9. By changing the light intensity ratio between the planar light emitter 1 and the additional light emitter 5, inspection with a plurality of chromaticities becomes possible.

  FIG. 11 is an explanatory diagram showing an example of inspection using an inspection light source. As shown in FIG. 11, the inspection light source 10 is preferably provided with a lens 7 that can collect the irradiation light of the planar light emitter 1. In this case, since the lens 7 collects the irradiation light in the direction of the inspection object 9, the difference in color becomes clear and visual determination is facilitated, and the inspection performance is improved. Moreover, since the irradiation light of the planar light emitter 1 is collected, the inspection can be performed with a smaller amount of light, and the planar light emitter 1 can be downsized. The lens 7 can be composed of a condenser lens. FIG. 11 shows an example having a flat planar light emitter 1 and a lens 7. Of course, the planar light emitter 1 having a curved portion may be used.

  FIG. 12 is an example of an inspection instrument provided with an inspection light source. This example is a portable inspection instrument 20. The inspection instrument 20 can be carried with one hand. Therefore, the inspection instrument 20 is excellent in handleability. The inspection instrument 20 includes an inspection light source 10 and a housing 21 that houses the inspection light source 10. The inspection light source 10 includes a planar light emitter 1 and an additional light emitter 5. The inspection instrument 20 has an internal power supply 3A. The internal power supply 3 </ b> A can be a part of the inspection light source 10. The internal power supply 3 </ b> A is housed inside the housing 21. In FIG. 12, the internal power supply 3A is indicated by a broken line. The wiring extending from the internal power supply 3A is also indicated by a broken line. The internal power supply 3A can be composed of a battery, a secondary battery, a rechargeable battery, or the like. The internal power supply 3A may be electrically connected to the planar light emitter 1 by a power feeding circuit. The inspection instrument 20 includes a power generation unit 22. The power generation unit 22 includes a solar panel 22A. The electric power generation part 22 is comprised with the solar cell. In the inspection instrument 20, electricity for causing the inspection light source 10 to emit light can be generated by itself. Therefore, the load on the environment can be reduced. The power generation unit 22 is not particularly limited as long as it is capable of self-power generation. For example, the power generation unit 22 may include a vibration power generation element that generates power by vibration. Since the inspection instrument 20 includes the inspection light source 10 as described above, the color can be easily discriminated visually and the inspection performance is improved. Moreover, since the inspection instrument 20 is portable, it is easy to handle. In addition, it cannot be overemphasized that the aspect of a test | inspection instrument is not limited to FIG.

  In the inspection light source 10 of the present disclosure, various color inspections are possible. The inspection object 9 includes a wide range of substrates, resin moldings, filters, metals, clothing, animals, plants, microorganisms, machines, and the like. The inspection light source 10 clarifies a color difference visually. For example, the inspection light source 10 can inspect dust, dirt, and scratches on the substrate. The inspection light source 10 can inspect dust, dirt, scratches, and the like of a molded product (for example, a resin molded product). Further, the inspection light source 10 can be applied not only to inspection of foreign matter but also to inspection for recognizing a color difference. For example, if light is applied to the skin of an animal including a person, pigments and blood vessels can be easily confirmed. It is also possible to inspect foreign objects in metals, clothes and cloth.

[Example]
Example 1
A planar light-emitting body 1 based on the layer configuration shown in FIG. 2B was produced. An outline of the planar light emitter 1 will be described below. The substrate 11 and the sealing material 15 are glass substrates having a thickness of 0.7 mm. The first electrode 12 is an ITO layer having a thickness of 150 nm. The organic light emitting layer 13 includes a first light emitting material-containing layer 32 having a thickness of 30 nm including a blue light emitting material “EM2” (the peak of the emission wavelength is 490 nm). The organic light emitting layer 13 includes a second light emitting material-containing layer 33 having a thickness of 30 nm including a red light emitting material “Ir (piq) ₂ (ACAC)” (the peak of the emission wavelength is 625 nm). The organic light emitting layer 13 does not contain a green light emitting material. A charge transfer layer including at least an intermediate layer and a hole transport layer is further disposed between the first light emitting material-containing layer 32 and the second light emitting material-containing layer 33. The first charge transfer layer 31 contains a hole transport layer. The second charge transfer layer 34 includes an electron transport layer. The second electrode 14 is an Al layer having a thickness of 90 nm. The first electrode 12 constitutes an anode, and the second electrode 14 constitutes a cathode. The planar light emitter 1 has an organic EL element having a multi-unit structure. The light emitting surface has a size of 80 mm × 80 mm. The planar light emitter 1 can be driven by a DC power source.

  A light source 10 for inspection based on the aspect of FIG. 2A was produced using the planar light emitter 1, the power feeding circuit 2, and the power source 3.

Electricity was supplied from a DC power source, and the chromaticity of irradiated light was measured when the inspection light source was driven at a luminance of 2000 cd / m ² . The chromaticity is represented by CIE (x, y). The chromaticity of the irradiation light in Example 1 is CIE (x, y) = (0.35, 0.30), which is within the region A1. This chromaticity exists in a triangle surrounded by C12, C16, and C19.

(Example 2)
The blue light emitting material was “TBP” (the peak of the emission wavelength was 450 nm). Other than that was the same as Example 1. The chromaticity of the irradiation light in Example 2 is CIE (x, y) = (0.20, 0.11), which is within the region A1. This chromaticity exists in a triangle surrounded by C00, C01, and C02.

(Example 3)
In Example 1, the concentration of the red light emitting material in the second light emitting material containing layer 33 was reduced to 1/10. This suppresses the intensity of red light emission and adjusts the light emission color. Otherwise, the same procedure as in Example 1 was performed. The chromaticity of the irradiation light in Example 3 is CIE (x, y) = (0.18, 0.19), which is within the region A1. This chromaticity exists in a triangle surrounded by C01, C10, and C11.

Example 4
In Example 1, the material and thickness of the light emitting layer were adjusted, and an inspection light source in which the chromaticity of irradiated light was within a triangle surrounded by C16, C17, and C21 was obtained.

(Example 5)
In Example 1, as the substrate 11 and the sealing material 15, a PEN film provided with a sealing inorganic film was used instead of the glass substrate. This PEN film is a flexible substrate. Otherwise, the same procedure as in Example 1 was performed. The planar light emitter 1 can be bent. The chromaticity of the irradiation light in Example 5 is CIE (x, y) = (0.35, 0.30), which is within the region A1.

(Example 6)
In Example 1, as the second electrode 14, a multilayer of ITO having a thickness of 100 nm, Ag having a thickness of 10 nm, and ITO having a thickness of 100 nm was used instead of the Al layer. This multilayer body is light transmissive. Otherwise, the same procedure as in Example 1 was performed. The planar light emitter 1 is light transmissive. The chromaticity of the irradiation light in Example 6 is in the area A1.

(Example 7)
A planar light emitter 1 of Example 1 was prepared. Further, in the planar light emitter 1 of Example 1, the planar light emitter using the blue light emitting material “EM2” instead of the red light emitting material as the light emitting material of the second light emitting material containing layer 33 is added to the additional planar light emitter. Prepared as 5A. The additional planar light emitter 5A has blue monochromatic light emission. The planar light emitter 1 and the additional planar light emitter 5A were arranged in parallel to form the inspection light source 10. The chromaticity of the irradiated light when both the planar light emitter 1 and the additional planar light emitter 5A emit light is within the region A1. The inspection light source 10 is configured such that the planar light emitter 1 and the additional planar light emitter 5A can be individually current controlled. Therefore, the chromaticity of the emission color can be adjusted.

(Example 8)
In Example 1, the size of the light emitting surface was 1 mm × 1 mm, and a condenser lens was disposed on the surface of the glass substrate on the light emitting surface side. Otherwise, the same procedure as in Example 1 was performed. The chromaticity of the irradiation light in Example 8 is in the area A1.

Example 9
In Example 1, a lithium ion battery was mounted on the inspection light source 10. The inspection light source 10 switches to power supply from a lithium ion battery at the time of a power failure (when power supply from an external power supply is stopped). Otherwise, the same procedure as in Example 1 was performed. The chromaticity of the irradiation light in Example 9 is in the area A1.

(Example 10)
A solar panel was attached to the inspection light source 10 of Example 9 to form an inspection instrument. This inspection instrument can be irradiated with light by self-power generation.

(Comparative Example 1)
In the planar light emitter 1 of Example 1, the white light emitting planar light emitter 1 was formed such that the organic light emitting layer 13 contained a green light emitting material. This was used as the light source of Comparative Example 1. The chromaticity of the irradiation light of this light source is outside the area A1.

(Comparative Example 2)
A sodium lamp was used as the light source of Comparative Example 2. The sodium lamp emits monochromatic light having a wavelength of around 590 nm. The chromaticity of the irradiation light of the sodium lamp is outside the area A1.

(Comparative Example 3)
A fluorescent lamp was used as the light source of Comparative Example 3. Fluorescent lamps emit white light. The chromaticity of the irradiation light of the fluorescent lamp is outside the area A1.

(Evaluation of the above examples and comparative examples)
Using each light source of the above-mentioned Examples and Comparative Examples, visual inspection of foreign matters in the resin molded product (inspection object) was performed. In the resin moldings in which no foreign matter was found in the comparative example, the foreign matter was found in the example. From this result, it is understood that the irradiation light whose chromaticity enters the region A1 as in Examples 1 to 10 improves the inspection property. In Example 1, the chromaticity is within the area A2, and it is particularly easy to distinguish green. Further, in Example 2, the chromaticity is in the region A2, the region A9, and the region A11, which is excellent in blue and green distinguishability, and the color discrimination is easy comprehensively. Further, in Example 3, the chromaticity is in the area A3 and the area A9, which is excellent in distinguishability between red and blue, and color discrimination is comprehensively easy. Further, in Example 4, the chromaticity is in the area A2 and in the area A10, and the red and green discrimination characteristics are excellent.

(Examples 11-23, Comparative Examples 4-15)
The light source for inspection of Examples 11 to 23 and Comparative Examples 4 to 15 is produced by deforming the light emitting layer of the planar light emitter of Example 1 (substitution of materials, change of thickness, addition of the number of light emitting layers). did. Examples 11-23 and Comparative Examples 4-15 emit light with chromaticity coordinates at the center of the MacAdam ellipse.

  Table 3 shows the configurations of the light emitting layers in Examples 11 to 23 and Comparative Examples 4 to 15. From Table 3, it is understood that chromaticity is adjusted by changes in the type and thickness of the luminescent material. When foreign substances were inspected in Examples 11 to 23 and Comparative Examples 4 to 15, it was confirmed that Examples 11 to 23 had high inspectability.

The light emitting materials described in Table 3 have the following emission wavelength peaks. As a blue light emitting material, “TBP” (450 nm), “EM2” (490 nm). As red light emitting materials, “Btp ₂ Ir (acac)” (615 nm), “Pq ₂ Ir (acac)” (590 nm), “Bt ₂ Ir (acac)” (580 nm). “Ir (ppy) ₃ ” (490 nm) as a green light emitting material. “EM2” and “Ir (ppy) ₃ ” have the same emission wavelength peak, but have different spectrum waveforms, and thus have different emission colors.

Claims (11)

A planar light emitter having a substrate, a first electrode, a second electrode paired with the first electrode, and an organic light emitting layer disposed between the first electrode and the second electrode is provided. ,
The organic light emitting layer has a plurality of light emitting materials,
The chromaticity of the irradiation light of the planar light emitter is included in a region formed by connecting the centers of the MacAdam ellipses whose area is smaller than 5 × 10 ⁻⁴ in the xy chromaticity diagram having a MacAdam ellipse magnified 10 times. Light source for inspection.   The inspection light source according to claim 1, wherein at least one of the plurality of light emitting materials is a blue light emitting material.   The inspection light source according to claim 1 or 2, wherein an angle between a major axis of the MacAdam ellipse forming the region and an x axis of the xy chromaticity diagram is larger than 0 degree and smaller than 90 degrees.   The inspection light source according to claim 1 or 2, wherein an angle between a major axis of the MacAdam ellipse forming the region and an x axis of the xy chromaticity diagram is greater than 70 degrees and smaller than 120 degrees.   The light source for inspection according to claim 1, wherein the light emitting surface of the planar light emitter includes a curved surface.   The inspection light source according to claim 5, wherein the substrate is a flexible substrate. The planar light emitter is light transmissive in a direction perpendicular to the surface of the substrate,
The light source for inspection according to any one of claims 1 to 6, wherein the irradiation light in the direction of the inspection object in the planar light emitter is stronger than light in a direction opposite to the inspection object. An additional light emitter having irradiation light of a chromaticity different from that of the planar light emitter;
The inspection light source according to claim 1, further comprising: a light intensity variable unit that changes the intensity of the irradiation light of the additional light emitter.   The inspection light source according to claim 1, further comprising a lens capable of condensing the irradiation light of the planar light emitter. A power feeding circuit electrically connected to the planar light emitter;
An inspection light source according to claim 1, further comprising: an internal power source that supplies electricity to the planar light emitter through the power feeding circuit.   An inspection instrument comprising the inspection light source according to claim 1 and a housing.

Images