JP4767706B2 - Integrating sphere adapter and photodetecting device having the same - Google Patents

Description

  The present invention relates to an adapter that is detachably attached to an integrating sphere that observes light to be measured emitted from a sample, and a photodetecting device including the adapter.

  An integrating sphere is used to measure the intensity of light emitted from the sample. The inner wall of the integrating sphere is made of a coating or material having high reflectivity and excellent diffusibility, and light incident on the inner wall is subjected to multiple diffuse reflection. The diffused light is incident on the photodetector and the output signal is guided to a light intensity meter to measure the light intensity.

  Examples of the sample that emits light include an organic EL element. An organic EL element is generally a light emitting element having a structure in which an anode, an organic layer including a light emitting layer, and a cathode are laminated on a substrate made of glass or a transparent resin material. The holes injected from the anode and the electrons injected from the cathode recombine in the light emitting layer, so that photons are generated and the light emitting layer emits light.

One of the items for evaluating the light emission characteristics of the organic EL element is the light emission efficiency. Furthermore, the light emission efficiency of the organic EL device includes an internal quantum efficiency defined by a ratio of the number of photons generated inside the device to the number of injected electrons, and a photon emitted outside the device with respect to the number of injected electrons. There is an external quantum efficiency defined as a percentage of numbers. The relationship between the internal quantum efficiency and the external quantum efficiency is as shown in the following formula (1).
η _ext ∝η _int × η _out (1)
In the equation, η _ext , η _int, and η _out represent the external quantum efficiency, the internal quantum efficiency, and the light extraction efficiency, respectively. The light extraction efficiency η _out is defined as the ratio of the number of photons emitted outside the device to the number of photons generated inside the device.

By the way, in an organic EL display configured using an organic EL element, photons that are not emitted to the outside from the substrate surface of the organic EL element due to total reflection at the boundary between the organic layer and the glass substrate contribute to light emission of the display. is not. For this reason, in order to evaluate the characteristics of organic EL elements, it is important to measure the quantum efficiency capable of evaluating the number of photons emitted outside the element, that is, to measure the external quantum efficiency with high accuracy and to compare the results. It is. An example of an apparatus capable of measuring the external quantum efficiency of an organic EL element is disclosed in FIGS.
JP 2004-309323 A

  The apparatus of Patent Document 1 has a mechanism in which a stage on which an organic EL element is placed moves up and down. By arranging the organic EL element so that only the surface of the organic EL element is exposed in the integrating sphere by this mechanism, the light emission characteristics from the surface of the organic EL element are measured. However, when the organic EL element is disposed at a position along the inner wall surface of the integrating sphere in order to expose only the surface of the organic EL element in the integrating sphere, the present inventors have reproducibility of the measurement result of the external quantum efficiency. Was found to be insufficient.

  Accordingly, an object of the present invention is to provide an adapter capable of measuring external quantum efficiency with sufficiently high reproducibility and a photodetection device including the adapter.

The light emitted radially from the organic EL element generally has an orientation pattern called a Lambertian type, and is assumed to have the same brightness and radiance in all emission directions. However, for example, when processing for improving the light extraction efficiency η _out of the organic EL element is performed on the surface of the glass substrate, light having directivity in a specific direction is significantly different from the Lambertian alignment pattern. May be emitted from the surface.

  When a sample that emits light to be measured having directivity in such a specific direction is placed at a position along the inner wall surface of the integrating sphere, measurement is performed depending on the directivity direction. Since the light to be measured is attenuated by the internal structure such as the light shielding plate, the reproducibility of the measurement result is insufficient.

  The inventors of the present invention have the initial directivity of the light to be measured emitted from the sample by introducing the light to be measured into the integrating sphere in a state where the light to be measured has directivity toward the center of the integrating sphere. It was found that the influence was sufficiently reduced and the influence of the internal structure of the integrating sphere could be reduced sufficiently. Based on this knowledge, the present inventors have earnestly studied an adapter that is arranged between the integrating sphere and the sample and can make the light to be measured have a directivity toward the center of the integrating sphere. As a result of the investigation, it was found that the measured light emitted from the sample can be directed toward the center of the integrating sphere by making the inner wall surface of the adapter into a tapered shape and diffusing and reflecting the measured light on the inner wall surface, The present invention has been completed.

  That is, the adapter according to the present invention is a cylindrical adapter that is detachably attached to an integrating sphere for observing light to be measured emitted from a sample, and is formed on the integrating sphere to introduce the light to be measured. A first end surface having a first opening connected to the light introduction hole, a second end surface having a second opening and contacting the sample, and the first opening and the second opening. And an inner wall surface that reflects the light to be measured, and the inner wall surface has a tapered shape that expands in the light guiding direction from the second end surface on the sample side to the first end surface on the integrating sphere side. The length in the light guide direction is longer than the diameter of the second opening.

  According to the adapter of the present invention, the light to be measured that has entered the tapered inner wall surface can be guided in the direction of the light introduction hole by being diffusely reflected by the inner wall surface. As a result, the light to be measured emitted from the sample is introduced into the integrating sphere from the light introduction hole in a state having directivity toward the center of the integrating sphere. Therefore, compared with the case where the sample is arranged at a position along the inner wall surface of the integrating sphere, the influence of the internal structure of the integrating sphere can be sufficiently reduced, and the external quantum efficiency can be measured with sufficiently high reproducibility. .

In the adapter according to the present invention, the ratio of the diameter (D ₁ ) of the first opening and the diameter (D ₂ ) of the second opening is D ₁ / D ₂ , and the inner wall surface of the adapter is tapered. Therefore, it is larger than 1, but is preferably 6 or less. If the value of D ₁ / D ₂ is within the above range, the light to be measured can be more reliably directed toward the center of the integrating sphere. Moreover, it is preferable that the taper-shaped expansion angle of the inner wall surface of an adapter is 30-70 degrees. When the taper-shaped spread angle is within the above range, the light to be measured can be more reliably directed toward the center of the integrating sphere.

Also, the adapter according to the present invention includes a reflection plate provided at a position facing the second opening, further Ru and a fixing means for fixing the reflector to the second end surface. When the adapter is provided with a reflecting plate and a fixing means for fixing the reflecting plate to the second end surface, the second opening of the adapter is covered with the reflecting plate in a state where the sample is not mounted. Preliminary measurement for obtaining a coefficient for correcting self-absorption by the sample can be easily performed. Note that self-absorption by a sample refers to a phenomenon in which light emitted from a sample is multiple-reflected in an integrating sphere and then enters the sample again, and a part of the light to be measured is absorbed by the sample.

  In the adapter according to the present invention, it is preferable that the fixing unit is a pressing unit that applies a pressing force to the reflecting plate in the direction of the second end surface. When the fixing means is a pressing means, it is easy to bring the reflector into contact with the second end surface without mounting the sample, and preliminary measurement for obtaining a coefficient for correcting self-absorption by the sample is easily performed. be able to. In addition to this, it is easy to sandwich the sample between the second end face of the adapter and the reflecting plate, and the sample can be easily attached to the adapter.

  Moreover, it is preferable that the adapter according to the present invention is configured to be inserted and attached to a position where the first end surface is continuous with the inner wall surface of the integrating sphere. When the adapter is attached so that the first end surface of the reflecting member and the inner wall surface of the integrating sphere form a continuous surface, the integrating sphere and the adapter are connected to each other as compared to the case where there is a step on these surfaces and is discontinuous The attenuation of the light to be measured in the portion is sufficiently reduced.

  The light detection apparatus according to the present invention includes the adapter according to the present invention described above, and an integrating sphere having a light introduction hole into which the adapter can be attached and into which light to be measured is introduced. According to the light detection device of the present invention, since the light to be measured is introduced from the light entrance with directivity toward the center of the integrating sphere, the influence of the internal structure of the integrating sphere can be sufficiently reduced. Can do. Thereby, the external quantum efficiency of the sample is measured with sufficiently high reproducibility.

  According to the present invention, the external quantum efficiency can be measured with sufficiently high reproducibility regardless of the direction of the light to be measured emitted from the sample.

  Hereinafter, preferred embodiments of the adapter according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same portions are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
The adapter according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a view showing a light detection device in a state in which the adapter of this embodiment is attached to the light introduction hole of the integrating sphere. In FIG. 1, a position where the light introduction hole is formed and a position passing through the center of the integrating sphere and on the opposite side thereof are used as both poles, and a straight line connecting these poles (hereinafter referred to as “center axis AX”). FIG. FIG. 2 is a view showing a cross section taken along the central axis AX and orthogonal to the cross section shown in FIG. Hereinafter, in the integrating sphere, a pole in which a light introduction hole is formed is referred to as a light introduction pole, and a pole on the opposite side is referred to as a counter pole.

  1 and 2 includes an integrating sphere 20 attached to the gantry 10, an adapter 30 attached to the light introduction hole 201, and a reference light unit 40 attached to the reference light unit introduction hole 202. And an optical fiber holder 50 for light detection mounted in the photodetector introduction hole 203 and a plug 100 for closing the spare hole 204 located at the opposite pole of the integrating sphere 20. The integrating sphere 20 is attached to the gantry 10 with a mounting screw 102.

The integrating sphere 20 is formed with a light introducing hole 201, a reference light unit introducing hole 202, a photodetector introducing hole 203, and a spare hole 204. In general, the opening area of these holes formed in the integrating sphere has the following restrictions. That is, if the surface area of a sphere having the same diameter as the inner wall of the integrating sphere (hereinafter referred to as “the same diameter sphere”) is 100, the opening area of each hole is desirably 10 or less. For example, a commercially available integrating sphere having an inner wall diameter of 8.4 cm (3.3 inches, surface area of the same sphere diameter: 221 cm ² ) has a hole with an opening area of 11.4 cm ² (diameter: 3.8 cm). is doing. In this case, the ratio of the opening area to the surface area of a sphere having the same diameter is about 5%.

  The inner wall surface 20a of the integrating sphere 20 is made of a diffuse reflection material. Examples of the diffuse reflection material include halon obtained by compressing and solidifying PTFE (polytetrafluoroethylene) powder, and resin powder compression-molding material obtained by baking, such as Spectralon and barium sulfate manufactured by Labsphere, USA. Since the inner wall surface 20a has a high reflectivity and excellent diffusibility, it is generally called a complete diffusion surface. Light incident on the perfect diffusion surface is scattered in all directions.

  The light introduction hole 201 is a hole for introducing the light to be measured. In the present embodiment, the adapter 30 is inserted and attached to the light introduction hole 201. A peripheral edge 201 a for abutting the adapter 30 is provided on the peripheral edge of the light introducing hole 201.

  The reference light unit introduction hole 202 is a hole into which the reference light unit 40 is inserted and attached. The reference light unit introduction hole 202 is formed on a meridian connecting the light introduction pole and the counter pole, and at a position equidistant from both the poles.

  The photodetector introduction hole 203 is a hole into which the optical fiber holder 50 for light detection is inserted and attached. The photodetector introduction hole 203 is formed on the equatorial plane of the integrating sphere 20 orthogonal to the central axis AX and at an angle of 90 ° with the reference light unit introduction hole 202.

  The preliminary hole 204 is formed at the position of the counter pole of the integrating sphere 20. In the present embodiment, the hole 204 is closed with the plug 100. The surface 100a of the plug 100 exposed in the integrating sphere 20 forms a continuous surface with the inner wall surface 20a of the integrating sphere 20, and is made of the same diffuse reflection material as the inner wall surface 20a of the integrating sphere 20.

  Light shielding plates 205 and 206 are disposed in the integrating sphere 20. The light shielding plate 205 is formed at a position that is spaced apart from and opposed to the photodetector introduction hole 203. The light shielding plate 206 is formed between the light introduction hole 201 and the photodetector introduction hole 203. The light shielding plates 205 and 206 are provided to prevent the light to be measured introduced from the light introduction hole 201 from directly entering the optical fiber 501. This is because when the light to be measured is directly incident on the optical fiber 501, a significant error occurs in the intensity data of the light to be measured.

  Next, the adapter 30 will be described with reference to FIGS. 3 and 4. FIG. 3 is a perspective view showing the adapter 30. 4 is a cross-sectional view taken along the line IV-IV and the center line AX in FIG.

  The adapter 30 is a cylindrical part having openings at both ends. The adapter 30 is attached to the light introducing hole 201 so that its central axis passes through the center of the integrating sphere 20. The adapter 30 is in contact with the reflecting member 31 whose inner wall surface is made of a diffuse reflecting material, the protection portion 32 that covers the outer peripheral surface of the reflecting member 31, and the peripheral portion 201 a of the light introducing hole 201. A flange portion 33 and a fixing screw 35 for locking the adapter 30 to the integrating sphere 20 are provided.

Each of the two ends of the reflecting member 31, the end surface (first end surface) 31F ₁ and end (second end surface) 31F ₂ is formed. An opening (first opening) 301 on the end face 31 </ b> F ₁ side is connected to the light introducing hole 201. On the other hand, with respect to the end face 31F ₂ is arranged such that the sample S comes into contact. As shown in FIG. 5, the sample S is disposed so that the light emitting element S < _b > ₁ included in the sample S faces the opening (second opening) 302 on the end face 31 </ _b > F ₂ side.

The inner wall surface 31a of the reflecting member 31 is a tapered shape whose diameter increases toward the light guiding direction from the end face 31F ₂ samples side to the end surface 31F ₁ of the integrating sphere side, the length of the light guiding direction of the reflecting member 31 L is longer than the diameter D ₂ of the opening 302. The inner wall surface 31 a is made of the same material as the diffuse reflection material that forms the inner wall surface 20 a of the integrating sphere 20. The reflection member 31 can be manufactured by cutting a diffuse reflection material such as Spectralon. Alternatively, the inner wall surface 31a of the reflecting member 31 may be configured by applying a diffuse reflector containing barium sulfate.

When the inner wall surface 31a has a tapered shape as described above, the light incident on the inner wall surface 31a is diffusely reflected with the intensity in the normal direction of the inner wall surface 31a being high, and is guided in the direction of the light introduction hole 201. . Further, the length L of the reflector 31 is longer than the diameter D ₂ of the opening 302, to be incident directly on the integrating sphere without incident on the measured light inner wall surface 31a emitted from the sample well Can be prevented. FIG. 5 shows how the light to be measured emitted from the sample S is guided in the direction of the integrating sphere 20. In addition, since the inner wall surface 31a is a complete diffusion surface like the inner wall surface 20a of the integrating sphere 20, the incident light is scattered in all directions. The completely diffusing surface has the property of reflecting the light in the normal direction most strongly.

Further, it the ratio of the diameter _{D 2} of diameter _{D 1} and the opening 302 of the aperture 301 of the reflective member _31, D 1 / _{D 2} is the inner wall surface 31a is greater than 1 for a tapered shape, is 6 or less Is preferable, and it is more preferable that it is 2-3. When D ₁ / D ₂ exceeds 6, there is a tendency that the directivity direction of the light to be measured cannot be sufficiently made the center direction of the integrating sphere. Moreover, it is preferable that it is 30-70 degrees, and, as for taper-shaped spreading angle (theta) shown by FIG. 4, it is more preferable that it is 35-50 degrees. When the spread angle θ is less than 30 °, the number of times of diffuse reflection of the light to be measured in the reflecting member 31 increases, and the light to be measured tends to attenuate. On the other hand, when the spread angle θ exceeds 70 °, there is a tendency that the directivity direction of the light to be measured cannot be sufficiently made the center direction of the integrating sphere.

  The protection part 32 consists of metal materials, and the reflection member 31 is engage | inserted inside this. A flange portion 33 having a larger outer diameter than the diameter of the light introduction hole 201 is provided on the outer peripheral surface of the protection portion 32. In the flange portion 33, a groove 33 a that fits with the peripheral portion 201 a of the light introduction hole 201 is formed along the outer peripheral surface of the protection portion 32. Further, when the fixing screw 35 provided on the flange portion 33 is tightened, the peripheral edge portion 201 a is sandwiched between the fixing screw 35 and the outer peripheral surface of the protection portion 33, and the adapter 30 is locked to the integrating sphere 20.

As shown in FIGS. 1 and 2, the adapter 30 is inserted and attached until the flange portion 32 and the peripheral edge portion 201 a of the integrating sphere 20 come into contact with each other. At this time, the end surface 31F ₁ of the reflecting member 31 is inserted to a position contiguous with the inner wall surface 20a of the integrating sphere. When the inner wall surface 20a of the end face 31F ₁ and the integrating sphere 20 is a continuous surface, the attenuation of the measured light is sufficiently reduced due to the discontinuity of the connecting portion of the reflecting member 31 and the integrating sphere 20 .

  The reference light unit 40 irradiates the integrating sphere 20 with a reference light source (not shown) when obtaining a correction coefficient for self-absorption by the sample S, and introduces reference light from the reference light source into the integrating sphere. Optical fiber 42. For example, a halogen lamp or a xenon lamp is used as the reference light source. The reference light source is turned on when the reference light is introduced into the integrating sphere 20, and is turned off when the reference light is not introduced. Note that a shutter (not shown) may be provided between the reference light source and the reference light introducing optical fiber 42, and the irradiation of the reference light in the integrating sphere 20 may be started or stopped by the shutter.

  The reference light unit 40 is mounted in the reference light unit introduction hole 202 and is positioned at an angle of 90 ° with the position of the adapter 30 where the sample S is disposed. For this reason, the irradiation light in which the inner wall surface 20a of the integrating sphere 20 is diffusely reflected enters the sample S. In the main measurement for measuring the intensity of the light to be measured, a part of the light to be measured diffusely reflected by the inner wall surface 20 a of the integrating sphere 20 enters the sample S. By making the reference light diffusely reflected on the sample S incident, the condition under which the light to be measured enters the sample S in this measurement can be made sufficiently close.

When measuring the external quantum efficiency of an organic EL element, a power source for supplying a current to the organic EL element is required. As such a power supply, the power supply unit 60 shown in FIG. 6 can be used. Power supply unit 60 includes a sample mounting unit 61 for mounting a sample S, and a unit Hongaibu (light blocking unit) 62 for accommodating the light emitting element S _1. A power source (not shown) for supplying current to the light emitting element S ₁ is separately provided outside the unit main body 62 in the present embodiment, but may be configured to be accommodated in the unit main body 62. Sample mounting the part 61, a reflector 63 provided in a position facing the end surface 31F ₂ of the adapter 30, a plurality of positive electrode terminal 64a which is disposed so as to sandwich the reflective plate 63 and a plurality of negative pole terminal 64b And are provided. A fixing screw 65 for locking the power supply unit 60 to the photodetecting device 1 is provided on the peripheral edge 62 a of the unit main body 62 on the sample mounting portion 61 side.

Surface opposite the end surface 31F ₂ of the reflector 63 is made of the same material as the diffuse reflection material on the inner wall surface 20a of the integrating sphere 20. The reflection plate 63 has a recess 63 a at a position corresponding to the opening 302 of the adapter 30. As a reflection plate 63 and the light emitting element S ₁ is not directly touch, it is for preventing the adhesion of scratches or soiling of the reflector 63. Recess 63a has a thickness in consideration of the depth of the light emitting element S _1, for example, it is formed by being dug to a depth of 0.2 mm.

  The positive electrode terminals 64a are each connected to the positive electrode of the DC power supply, while the negative electrode terminals 64b are connected to the negative electrode of the DC power supply. The positive electrode terminal 64a and the negative electrode terminal 64b are both pressed by a spring (not shown) built in the side opposite to the side on which the sample S is placed, and project onto the sample mounting portion 61. ing.

(Measurement method of external quantum efficiency)
Next, a method for measuring the external quantum efficiency of the sample S using the adapter 30 according to this embodiment will be described. The external quantum efficiency of the sample S can be obtained by measuring the spectral intensity of the light to be measured emitted from the sample.

First, a sample provided with an organic EL element on a glass substrate is prepared. Samples S _EL shown in FIG. 7, the glass substrate 52 processed has been subjected squares for improving light extraction efficiency on the surface, and an organic EL element 51 formed on the glass substrate surface 52F ₁ Yes. The organic EL element 51 is formed in the center portion of the glass substrate surface 52F _1, an anode, an organic layer and a cathode comprises a light-emitting layer has a stacked structure. The glass substrate surface 52F ₁ is further transparent wiring 54a connected respectively to the anode and the cathode, the wiring 54b is formed. As the glass substrate 52, a 20 mm square or 40 mm square glass plate can be used.

Hereinafter, a method for measuring the external quantum efficiency in the main measurement after performing the preliminary measurement for obtaining the self-absorption correction coefficient by the sample _SEL will be described. Incidentally, when the correction coefficient according to the self-absorption of the sample S _EL is known, it is not always necessary to perform the preliminary measurement.

<Preliminary measurement>
Preliminary measurement, the second preliminary measurement for measuring a first preliminary measurement for measuring the spectral intensity E ₁ of the reference light without mounting a sample S _EL, the spectral intensity E ₂ of the reference light in the state of mounting the sample S _EL It consists of. The apparatus and measurement method used for the preliminary measurement will be described with reference to FIGS.

  The first preliminary measurement is performed according to the following procedure. That is, first, the adapter 30 is attached to the light introducing hole 201 of the integrating sphere 20 to assemble the photodetecting device 1 shown in FIGS.

Then, the specimen mounting portion 61 of the power supply unit 60 mounting the power unit 60 to the photodetector 1 in a state without mounting a sample S _EL. The power supply unit 60 is fixed to the light detection device 1 by a fixing screw 65 provided in the power supply unit 60. FIG. 8 is a cross-sectional view showing a joint portion between the power supply unit 60 and the adapter 30 when the sample _SEL is not mounted. When the sample _{S EL} between the end face 31F ₂ samples placement portion 61 and the adapter 30 is not arranged, plus pole terminal 64a and negative electrode terminal 64b is pushed by the end surface 31F _2. Therefore, the reflection plate 63 of the power supply unit 60 is abutted against the end face 31F ₂ of the adapter 30, while the opening 302 of the adapter 30 is in a state of being covered by the reflection plate 63.

In this state, the reference light is introduced into the integrating sphere 20. The introduced reference light is incident on the optical fiber 501 attached to the light detection optical fiber holder 50. The optical fiber 501 is connected to a photodetector (not shown), for example, a multi-channel photodetector. Accordingly, the reference light incident on the optical fiber 501 is guided to the multichannel photodetector through the optical fiber 501. Measurement data multichannel light detector detects is output to the data processing device (not shown) is data processing, the spectrum intensity E ₁ of the reference light is measured.

The second preliminary measurement is performed according to the following procedure. That is, the power supply unit 60 is removed from the light detection device 1 and the power supply unit 60 is attached again in a state where the sample _SEL is placed on the sample placement portion 61. FIG. 9 is a cross-sectional view showing a cross section of the joint between the power supply unit 60 and the adapter 30 when the sample _SEL is mounted. In this case, the sample _{S EL,} the position and the glass substrate surface 52F ₁ and sample placing portion 61 with a direction opposing the wiring 54a and the wiring 54b are respectively connected to the positive electrode terminal 64a and negative terminal 64b Placed in.

When the sample _{S EL} is disposed between the end face 31F ₂ samples placement portion 61 and the adapter 30, plus pole terminal 64a and negative electrode terminal 64b is pressed by the glass substrate surface 52F ₁ of the sample _{S EL.} Therefore, the reflection plate 63 of the power supply unit 60 is in contact with the glass substrate 52F _1, while the opening 302 of the adapter 30 is in a state of being covered with the glass substrate surface 52F _2. At this time, the organic EL element 51 of the sample _{S EL} is arranged at a position facing the opening 302. Here, no current is supplied to the organic EL element 51, and the organic EL element 51 is not emitting light.

The reference light is introduced into the integrating sphere 20 in a state, measuring the spectral intensity E ₂ of the measuring method and the reference light in the same spectral intensity E ₁ in the first preliminary measurement. The irradiated reference light is incident on the optical fiber 501 attached to the light detection optical fiber holder 50. However, since a part of the irradiated reference light is absorbed by the sample _SEL , the spectral intensity E ₂ value is smaller than the value of the spectral intensity E _1. From these measured values, the self-absorption rate A by the sample _SEL is calculated by the following equation (2).
_{A = E 2 / E 1 (} 2)

<Main measurement>
After the first and second preliminary measurements are completed, the main measurement is performed according to the following procedure. That is, a current is supplied to the organic EL element 51 to cause the organic EL element 51 to emit light. Transmitted through the glass substrate 52, light emitted from the glass substrate 52F ₂ is the measured light in the measurement of the external quantum efficiency. The light to be measured is introduced into the integrating sphere 20 through the adapter 30. The light to be measured is multiple-reflected by the inner wall surface 20 a of the integrating sphere 20, and a part of the light enters the optical fiber 501 attached to the light detection optical fiber holder 50. Then, the spectral intensity E _{3 of the} light incident on the optical fiber 501 is measured in the same manner as the reference light in the preliminary measurement.

Spectral intensity was measured as described above E ₃ is an under-estimated values for the uncorrected self-absorption by the sample S _EL. Therefore, the spectrum intensity E obtained by correcting the error due to the self-absorption rate using the self-absorption rate A measured in the preliminary measurement is calculated by the following equation (3).
E = E ₃ / A (3)

Based on the spectral intensity E, it is possible to calculate the total luminous flux emitted from the glass substrate 52F ₂ samples S _EL. The external quantum efficiency of the organic EL element can be obtained from the value of the spectral intensity E thus measured and the current value supplied to the organic EL element.

(Second Embodiment)
An adapter according to a second embodiment of the present invention will be described with reference to FIG. FIG. 10 is a cross-sectional view showing a state in which the sample _SEL and the reflection plate 81 are attached to the adapter 80 of the present embodiment. Adapter 80, the reflector 81 in the preliminary measurement, the sample S _EL via the reflecting plate 81 in the present measurement, brought into contact with the end face 31F _2, the first embodiment in including a pressing means for retaining This is different from the adapter 30 of FIG.

  The reflector 81 is made of the same material as the diffuse reflection material of the inner wall surface 20a of the integrating sphere 20. The reflection plate 81 has a recess 81 a at a position corresponding to the opening 302 of the adapter 80. The recess 81a prevents the reflection plate 81 and the organic EL element 51 from coming into direct contact with each other and prevents the reflection plate 81 from being scratched or soiled. The recess 81a is dug down to a depth of 0.2 mm, for example.

Adapter 80 includes a pressing means as the fixing means for fixing the reflecting plate 81 on the end face 31F ₂ adapter 80. In the present embodiment, the pressing means includes a pair of metal pieces 82 and a pair of support bars 83 for fixing the metal pieces 82. The pair of support rods 83 are provided at positions where the opening 302 of the adapter 80 is sandwiched on the surface 33b opposite to the surface having the groove 33a of the flange portion 33. The base end portion of the metal piece 82 is fixed to the tip of the support bar 83. On the other hand, the tip of the metal piece 82 extends in the direction of the central axis AX so that the reflecting plate 81 can be brought into contact therewith.

According to the adapter 80, the sample _SEL can be easily attached to the adapter 80. Further, when the adapter 80 is attached to the integrating sphere 20, the sample _SEL can be performed while being fixed to the adapter 80. Therefore, it is possible to prevent the position of the sample S _EL is shifted, thereby improving workability of the measurement. Further, according to the adapter 80, it is possible to fix the reflector 81 to the end surface 31F ₂ by the pressing means. For this reason, the preliminary measurement which measures the self-absorption rate by a sample can be performed easily. In addition to this, it is not always necessary to use a power supply device such as the power supply unit 60 provided with electrode terminals and reflectors with built-in springs. For this reason, the freedom degree of a power supply device improves. The method of measuring the external quantum efficiency of the sample _SEL using the adapter 80 can be performed in the same manner as the method in the first embodiment except for the step of arranging the sample _SEL and the step relating to the power supply unit.

(Third embodiment)
An adapter according to a third embodiment of the present invention will be described with reference to FIG. FIG. 11 is a cross-sectional view showing a state in which the sample _SEL is mounted on the adapter 90 of this embodiment. Adapter 90 includes a reflector 91 provided in a position facing the end surface 31F _2, the first embodiment in including a gap adjusting screw (pressing means) 92 for adjusting the distance between the end face 31F ₂ and the reflecting plate 91 This is different from the adapter 30 of FIG.

  The reflector 91 is made of the same material as the diffuse reflection material of the inner wall surface 20a of the integrating sphere 20. The reflection plate 91 has a recess 91 a at a position corresponding to the opening 302 of the adapter 90. The reflection plate 91 is covered and held by a metal member 95 except for the surface having the recess 91a. The recess 91a is for preventing the reflection plate 91 and the organic EL element 51 from directly touching each other and preventing the reflection plate 91 from being scratched or soiled. The recess 91a is dug down to a depth of 0.2 mm, for example.

The interval adjusting screw 92 is formed with a tip end portion 92a that is rotatably locked to the surface 33b of the flange portion 33, a threaded portion 92b that is threaded, and a hexagonal surface that is used to rotate the threaded portion 92b. A proximal end portion 92c. The threaded portion 92 b meshes with threading (not shown) of the inner surface of the through hole provided in the vicinity of the outer edge portion of the metal member 95. Thus, it is possible to move the position of the metal member 95 by rotating the proximal end, can adjust the gap between the end face 31F ₂ and the reflection plate 91. Placing the sample _{S EL} on the reflection plate 91 and rotating the proximal end, can contact place of the sample _{S EL} the end face 31F _2. Incidentally, when the preliminary measurement, the sample rotates a proximal end 92c and without placed on the reflection plate 91, it is sufficient to contact the reflective plate 91 to the end surface 31F _2.

According to the adapter 90, the sample _SEL can be easily attached to the adapter 80. Further, when the adapter 90 is attached to the integrating sphere 20, the sample _SEL can be performed while being fixed to the adapter 90. Therefore, it is possible to prevent the position of the sample S _EL is shifted, thereby improving workability of the measurement. Furthermore, in the adapter 90 is provided with a reflecting plate 91 is adjustable by the reflection plate 91 and the spacing interval adjusting screw 92 with the end surface 31F _2, the sample _{S EL} between the reflective plate 91 and the end surface 31F ₂ holding Is done. For this reason, the preliminary measurement which measures the self-absorption rate by a sample can be performed easily. In addition to this, it is not always necessary to use a power supply device such as the power supply unit 60 including an electrode terminal with a reflecting plate or a spring built therein. For this reason, the freedom degree of a power supply device improves. The method of measuring the sample _SEL external quantum efficiency using the adapter 80 can be performed in the same manner as the method in the first embodiment except for the step of mounting the sample _SEL and the step of the power supply unit.

  As mentioned above, although embodiment of this invention was described in detail, it is not restricted to the said embodiment, Various deformation | transformation are possible. For example, the adapter according to the present invention may have the following configuration. That is, for example, a temperature adjusting unit capable of cooling or heating the sample may be provided. Examples of such temperature adjusting means include means for circulating a fluid such as water or gas inside the reflector on which the sample is placed. In particular, as a means for cooling the sample, a cooling device including a Peltier element can be cited. The Peltier element is preferably installed directly on the sample or on the reflector. Moreover, although the multichannel photodetector was illustrated as a photodetector, photodetectors, such as a photomultiplier tube, may be sufficient.

  According to the present invention, there is an effect that the light to be measured can be introduced into the integrating sphere with directivity toward the center of the integrating sphere. For this reason, the use of the present invention is not limited to the measurement of the external quantum efficiency of the organic EL element. The adapter and the light detection apparatus according to the present invention are also useful for measuring the light emission characteristics of an element that emits light with a biased orientation distribution or a light emitting element that is irradiated with light at a wide angle.

It is sectional drawing which shows the photon detection apparatus using the adapter which concerns on 1st Embodiment. It is sectional drawing which shows the photon detection apparatus using the adapter which concerns on 1st Embodiment. It is a perspective view which shows the adapter which concerns on 1st Embodiment. It is sectional drawing which shows the adapter which concerns on 1st Embodiment. It is sectional drawing which shows a mode that the light emitted from the sample S is guide | induced to the integrating sphere. It is a perspective view which shows a power supply unit. It is a schematic cross section which shows a sample provided with an organic EL element. It is an expanded sectional view which shows the connection part of the adapter and power supply unit when not mounting _| wearing with the sample _SEL . It is an expanded sectional view which shows the connection part of the adapter and power supply unit at the time of mounting _| wearing with sample _SEL . It is sectional drawing which shows the adapter which concerns on 2nd Embodiment. It is sectional drawing which shows the adapter which concerns on 3rd Embodiment.

Explanation of symbols

S, S _EL ... sample, 1, 11 ... photodetection device, 20 ... integrating sphere, 201 ... light introduction hole, 30, 80, 90 ... adapter, 301 ... opening (first opening), 302 ... opening (second) ), 31F ₁ ... end face (first end face), 31F ₂ ... end face (second end face), 63, 81, 91 ... reflector, 92 ... interval adjusting screw (pressing means).

Claims (4)

A cylindrical adapter detachably attached to an integrating sphere for observing light to be measured emitted from a sample,
A first end surface having a first opening connected to a light introduction hole formed in the integrating sphere for introducing the light to be measured, and a first end surface having a second opening and the sample being brought into contact therewith. Two end surfaces, an inner wall surface provided between the first opening and the second opening for reflecting the light to be measured, a reflecting plate provided at a position facing the second end surface, Fixing means for fixing the reflecting plate to the second end surface ;
The inner wall surface has a tapered shape that expands in a light guiding direction from the second end surface on the sample side to the first end surface on the integrating sphere side, and the length in the light guiding direction is An adapter characterized by being longer than the diameter of the second opening. The adapter according to claim 1 , wherein the fixing unit is a pressing unit that applies a pressing force to the reflecting plate in the direction of the second end surface. The adapter according to claim 1 or 2 , wherein the first end face is configured to be inserted and attached to a position that is continuous with an inner wall surface of the integrating sphere. The adapter according to any one of claims 1 to 3 ,
An integrating sphere having a light introduction hole into which the adapter can be attached and light to be measured is introduced;
An optical detection device comprising:

Images