JP5580519B2 - Light source device for sensitivity calibration - Google Patents

Description

  The present invention relates to a light source device used for sensitivity calibration of a photodetector (for example, a photomultiplier tube) for measuring weak light such as bioluminescence or chemiluminescence.

  Conventionally, as a technique in such a field, there is JP-A-3-262931, which discloses various types of light sources for sensitivity calibration. As a first example, light emitted from an LED (semiconductor light-emitting element) is incident on an optical fiber through a pinhole, and the optical fiber is connected to the incident surface of the photomultiplier tube. Sensitivity calibration is performed. As a second example, the light emitted from the LED is reflected by the transparent glass reflector, and this light is incident on the optical fiber through the pinhole, and the optical fiber is connected to the incident surface of the photomultiplier tube. The sensitivity of the photomultiplier tube is calibrated. As a third example, the light emitted from the LED is made incident on the scattering plate through a pinhole, and the scattered light is made incident on the incident surface of the photomultiplier tube, thereby calibrating the sensitivity of the photomultiplier tube. Yes.

JP-A-3-262931

  However, none of the above-described conventional sensitivity calibration light source devices are intended to generate vertically long light. For example, weak light such as bioluminescence or chemiluminescence generated in a test tube is photoelectron-generated. When measuring with a multiplier, it is very important to calibrate the sensitivity according to the vertically long light emission region in order to perform accurate calibration of the photomultiplier.

  It is an object of the present invention to provide a sensitivity calibration light source device that uniformly generates vertically long light from a translucent cover.

The present invention relates to a light source device for calibrating the sensitivity of a photodetector.
A semiconductor light emitting device housed in a housing;
A power source for supplying electricity to the semiconductor light emitting device;
A light guide into which the light of the semiconductor light emitting element is incident from the rear end surface;
A light-transmitting cover that is connected to an end of the housing and surrounds the light guide and diffuses light from the light guide;
The portion surrounded by the light-transmitting cover in the light guide has a plurality of light emitting portions in the central axis direction of the light guide,
A mounting table for fixing the light guide is provided at the end of the housing,
The translucent cover has an insertion hole into which the light guide is inserted, a gap is provided around the entire circumference of the light guide in the insertion hole, and the tip of the translucent cover is formed in a hemispherical shape ,
The light guide consists of a single optical fiber,
The light emitting portion on the front end side of the portion surrounded by the light-transmitting cover in the optical fiber is formed as a tapered portion whose diameter gradually decreases toward the tip, and the portion surrounded by the light-transmitting cover in the optical fiber The light emitting part on the rear end side is formed as a reduced diameter part having a concave shape over the entire circumference,
The tapered portion and the reduced diameter portion of the optical fiber are characterized in that the core portion is exposed by removing the cladding layer .

  In this light source device for sensitivity calibration, light is emitted from a semiconductor light emitting element (for example, LED or LD) housed in a housing, and this light is incident on the rear end surface of the light guide, so that the light is transmitted into the translucent cover. Can guide light. Since the light guide has a plurality of light emitting portions in the central axis direction within the light transmitting cover, the position of each light emitting portion is changed at the time of designing in consideration of the material and length of the light transmitting cover. Only vertically long light can be uniformly generated from the light-transmitting cover in the central axis direction.

Further, it is preferable that the translucent cover is formed with an insertion hole into which the light guide is inserted, and a gap is provided between the front end surface of the light guide and the bottom surface of the insertion hole.
Since this gap is used as a space for diffusing light, it contributes to the uniformity of light emitted from the front side of the translucent cover.

The light guide is made of a single optical fiber, and the light emitting portion on the front end side of the portion of the optical fiber surrounded by the translucent cover is formed as a tapered portion that gradually decreases in diameter toward the tip. The light emitting portion on the rear end side of the portion of the optical fiber surrounded by the translucent cover is formed as a reduced diameter portion having a concave shape over the entire circumference, and the tapered portion and the reduced diameter portion of the optical fiber are clad It is preferable that the core is exposed by removing the layer.
Since the light emitting portion on the front end side of the optical fiber is formed as a tapered portion whose diameter gradually decreases toward the tip, a light emitting region is created on the front end side in the central axis direction of the optical fiber, and the rear end side is contracted. A light emitting region is also created in the diameter portion, and thus, the translucent cover can be illuminated vertically and uniformly in the central axis direction. Furthermore, since both the reduced diameter portion and the tapered portion are formed over the entire circumference of the optical fiber, the translucent cover can be illuminated uniformly over the entire circumference. In addition, since the reduced diameter portion has a concave shape over the entire circumference of the optical fiber, various measures can be taken by changing the depth. For example, when the depth of the reduced diameter portion is increased, light leakage at the reduced diameter portion increases, whereby the light flux toward the tapered portion becomes weak, and the light emission amount at the tapered portion can be reduced. On the other hand, when the depth of the reduced diameter portion is reduced, light leakage at the reduced diameter portion is reduced, thereby increasing the luminous flux toward the tapered portion and increasing the light emission amount at the tapered portion. Can do. As described above, the reduced diameter portion has a function of adjusting the light emission of the tapered portion as well as the light emission itself.

Further, it is preferable that a light incident hole having an opening area smaller than the area of the rear end surface of the light guide is disposed between the semiconductor light emitting element and the rear end surface of the light guide.
By appropriately changing the opening area of the light incident hole, the amount of light incident on the light guide from the semiconductor light emitting element can be easily adjusted with a simple configuration and without application of a neutral density filter.

Further, the light guide is composed of a plurality of optical fibers, and the position of the front end surface of each optical fiber is preferably different in the direction of the central axis of the light guide within the translucent cover.
In such a case, since the positions of the end faces of the optical fibers are different from each other, light can be emitted at different positions in the central axis direction, thereby generating vertically long light from the translucent cover in the central axis direction. Can be made.

The semiconductor light emitting element is fixed on the base plate, and a light detection element that receives light from the semiconductor light emitting element is fixed to the base plate. The base plate is based on a signal from the light detection element. It is preferable to be electrically connected to a control board that controls the power supplied to the.
By adopting such a configuration, the light emitted from the semiconductor light emitting element can be directly received by the light detecting element, so that the light quantity of the semiconductor light emitting element can be feedback-controlled with high accuracy.

  According to the present invention, vertically long light can be uniformly generated from the translucent cover.

  Hereinafter, preferred embodiments of a light source device for sensitivity calibration according to the present invention will be described in detail with reference to the drawings. In this embodiment, since the tube axis of the housing 2, the optical axis of the optical fiber F, and the center axis of the light guide are substantially the same, the symbol “L” is used in common.

  As shown in FIGS. 1 and 2, the light source device 1 has a sensitivity of a photodetector (for example, a photomultiplier tube (PMT)) for measuring weak light such as bioluminescence and chemiluminescence performed in a test tube. This is for calibration. The light source device 1 has substantially the same shape as a test tube used in a blood test apparatus, and has a total length of about 80 mm and a diameter of about 10 mm.

  The light source device 1 includes a cylindrical tubular housing 2 made of stainless steel, aluminum, or the like, and a vertically long translucent cover made of a material (for example, fluorine resin) that is screwed at the tip of the housing 2 to diffuse light. (Light diffusion cover) 20, and the tip of the light-transmitting cover 20 has a round hemispherical surface 20 a like a test tube. The housing 2 is screwed to a main body 2a that accommodates the control board 3, an extension 2b that is screwed to the front end of the main body 2a, and an inner cylinder 5 that is fixed to the rear end of the main body 2a. And a cap portion 2c.

  A control board 3 is accommodated in the main body 2a. An ON / OFF switch element 4 is fixed to the control board 3, and an operation lever 4a of the ON / OFF switch element 4 is exposed from the main body 2a. . The extension portion 2b is integrated with the outer cylinder portion 2bA screwed to the main body portion 2a, the resin inner cylinder portion 2bB press-fitted into the outer cylinder portion 2bA, and the inner cylinder portion 2bB, and the tube axis L It comprises a fiber mounting table 2bC that protrudes in the direction and fixes a resin optical fiber F having a diameter of approximately 1.5 mm.

  The fiber mounting table 2bC has a cylindrical shape and has a male screw portion 6 for screw coupling to the translucent cover 20. In the center of the fiber mounting table 2bC, the optical fiber insertion hole 7 is positioned on the tube axis L, and the proximal end side of the optical fiber (light guide) F is inserted and fixed. A light incident hole 8 communicating with the fiber insertion hole 7 is formed. The opening area of the light incident hole 8 is smaller than the area of the rear end face 21 (see FIG. 3) of the optical fiber F, and is formed as a pinhole.

  Between the inner cylinder part 5 and the cap part 2c of the main body part 2a, a button battery (power source) 10 for energizing the control board 3 is accommodated, and the cap part 2c is detachable from the main body part 2a, The battery 10 can be replaced by removing the cap 2c.

  The control board 3 extends in the tube axis L direction within the main body 2a, the rear end of the control board 3 is fixed to the inner cylinder 5 of the main body 2a, and a disc-like shape is formed at the front end of the control board 3. A base plate 11 is fixed. A white LED 12 that is an example of a semiconductor light emitting element and a photodiode (PD) 13 that is an example of a light detection element that receives light emitted from the LED 12 are fixed to the base plate 11, and the LED 12 and the photodiode 13 are fixed. Is supplied with electricity via the control board 3 connected to the battery 10. The LED 12 is not limited to a white light LED, and an LED having a desired emission wavelength can be used in accordance with the emission wavelength of the reagent.

  The LED 12 is located on the tube axis L at the center of the base plate 11, and the photodiode 13 is adjacent to the LED 12. Further, the LED 12 and the photodiode 13 are surrounded by a black inner cylinder portion 2bB. With such a configuration, the light from the LED 12 can be directly and reliably detected by the photodiode 13.

  The base plate 11 to which the LED 12 and the photodiode 13 are fixed is electrically connected to the control board 3 that controls the power supplied to the LED 12 based on the signal from the photodiode 13. When such a configuration is adopted, the light emitted from the LED 12 can be directly received by the photodiode 13, and therefore the light amount of the LED 12 can be feedback-controlled with high accuracy.

  The light from the LED 12 located on the tube axis L reaches the light incident hole 8 through the space S surrounded by the inner cylindrical portion 2bB. Then, the light enters from the rear end surface 21 (see FIG. 3) of the optical fiber F and is guided into the translucent cover 20. The translucent cover 20 is formed with an insertion hole 22 for inserting one optical fiber F inserted and fixed in the optical fiber insertion hole 7, and the insertion hole 22 includes the optical fiber insertion hole 7 and the light incident. Like the hole 8, it is formed on the tube axis L.

  As shown in FIG. 3, a portion of the optical fiber F surrounded by the light transmitting cover 20, that is, a portion (hereinafter referred to as “effective portion”) A disposed in the insertion hole 22 is an optical axis of the optical fiber F. Two light emitting portions 23 and 24 are provided in the L direction.

  The light emitting portion 23 on the front end side of the effective portion A is formed as a tapered portion that gradually decreases in diameter toward the tip, and the light emitting portion 24 on the rear end side of the effective portion A is a constriction that is concave over the entire circumference. It is formed as a diameter part. The reduced diameter portion 24 is preferably close to the fiber mounting table 2bC. Further, the tapered portion 23 and the reduced diameter portion 24 of the optical fiber F expose the core portion C by removing the cladding layer G, so that the light in the optical fiber F can be emitted from the location to the outside. . The total length of the effective portion A is about 11 mm. When this total length is 1, the tapered portion 23 is about 0.15 to 0.2, and the reduced diameter portion 24 is about 0.1. .

  In this sensitivity calibration light source device 1, light is emitted from the LED 12 housed in the housing 2, and this light is incident from the rear end face 21 of the optical fiber F, thereby guiding the light into the translucent cover 20. be able to. In the translucent cover 20, the optical fiber F has two light emitting portions 23 and 24 in the direction of the optical axis L. Therefore, considering the material and length of the translucent cover 20, By simply changing the positions of the light emitting units 23 and 24 at the time of design, vertically long light can be uniformly generated from the translucent cover 20 in the tube axis L direction.

  Since the light emitting portion 23 on the front end side in the optical fiber F is formed as a tapered portion whose diameter gradually decreases toward the tip, a light emitting region is created on the front end side in the optical axis L direction of the optical fiber F. In addition, a light emitting region is also created in the reduced diameter portion 24 on the rear end side, whereby the light-transmitting cover 20 can be illuminated uniformly in the longitudinal direction in the tube axis L direction. Furthermore, since both the reduced diameter portion 24 and the tapered portion 23 are formed over the entire circumference of the optical fiber F, the light transmitting cover 20 can be uniformly illuminated over the entire circumference.

  Further, since the reduced diameter portion 24 has a concave shape over the entire circumference of the optical fiber F, various measures can be taken by changing the depth. For example, when the depth of the reduced diameter portion 24 is increased, light leakage at the reduced diameter portion 24 increases, thereby reducing the light flux toward the tapered portion 23 and reducing the amount of light emitted from the tapered portion 23. be able to. On the other hand, when the depth of the reduced diameter portion 24 is reduced, light leakage at the reduced diameter portion 24 is reduced, thereby increasing the luminous flux directed toward the tapered portion 23 and light emission at the tapered portion 23. The amount can be increased. Thus, the reduced diameter portion 24 has a function of adjusting the light emission of the tapered portion 23 as well as the light emission itself.

  Further, a gap R is provided between the front end surface 26 of the optical fiber F and the bottom surface 22 a of the insertion hole 22. In this gap R, the distance between the tip surface 26 and the bottom surface 22a of the optical fiber F is preferably equal to or greater than the diameter of the optical fiber F. In this embodiment, the resin optical fiber F having a diameter of approximately 1.5 mm is used. For this, 1 to 3 mm is appropriate. Since this gap R is used as a space for diffusing light, it contributes to the uniformity of light emitted from the hemispherical surface 20a of the translucent cover 20.

  Furthermore, between the LED 12 and the rear end face 21 of the optical fiber F, as described above, the light incident hole 8 having an opening having a smaller diameter than the optical fiber F is formed as a pinhole. By appropriately changing the opening area of the hole 8, the amount of light incident on the optical fiber F from the LED 12 can be easily adjusted with a simple configuration and without application of a neutral density filter.

  Reference numeral 27 denotes a dimming unit for adjusting the amount of current supplied to the LED 12 by rotating it by a predetermined angle by a precision driver.

  It goes without saying that the present invention is not limited to the embodiment described above.

  As shown in FIGS. 4 and 5, the light source device 30 for sensitivity calibration according to another embodiment has a light guide P composed of seven optical fibers P1, P2, P3, P4, P5, P6, and P7. The optical fibers P1 to P7 are fixed to the fiber mounting table 2bC, and the effective portion A is inserted into the insertion hole 22 of the light transmitting cover 20. In the effective portion A, the positions of the end faces P1a, P2a, P3a, P4a, P5a, P6a, and P7a of the optical fibers P1 to P7 are within the translucent cover 20 in the direction of the central axis L of the light guide P. Each is different.

  Further, a gap R is provided between the front end surface P 1 a of the light guide P and the bottom surface 22 a of the insertion hole 22.

  In such a configuration, light is emitted from the end faces P1a to P7a of the optical fibers P1 to P7, and light is emitted at different positions in the translucent cover 20 in the direction of the central axis L. Vertically long light in the L direction can be uniformly generated from the translucent cover 20.

The number of optical fibers of the light guide P applied to the sensitivity calibration light source device 30 may be two or more. In addition, the light source device 30 according to this embodiment has the same components as the light source device 1, and common portions are denoted by the same reference numerals and description thereof is omitted.

  A laser diode (LD) may be applied as the semiconductor light emitting element.

  The optical fibers F and P1 to P7 may be made of glass or resin.

It is a perspective view showing one embodiment of a light source device for sensitivity calibration concerning the present invention. It is a longitudinal cross-sectional view of the light source device shown in FIG. It is a principal part expanded sectional view of the light source device shown by FIG. It is a principal part expanded sectional view which shows other embodiment of the light source device for sensitivity calibration which concerns on this invention. It is a top view which shows the arrangement | sequence of the optical fiber applied to the light source device shown by FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,30 ... Light source device for sensitivity calibration, 2 ... Housing, 3 ... Control board, 8 ... Light incident hole, 10 ... Battery (power source), 11 ... Base plate, 12 ... LED (semiconductor light emitting element), 13 ... Photo Diode (light detecting element), 20 ... translucent cover, 21 ... back end surface of optical fiber, 22 ... insertion hole, 22a ... bottom surface of insertion hole, 23 ... tapered portion (light emitting portion), 24 ... reduced diameter portion (light emitting portion) ), 26... Optical fiber tip, 31. Light guide rear end, F. Optical fiber (light guide), P1 to P7. Optical fiber, P. Light guide, A. Axis, center axis, R ... gap.

Claims (5)

In the light source device for calibrating the sensitivity of the photodetector,
A semiconductor light emitting device housed in a housing;
A power supply for supplying electricity to the semiconductor light emitting device;
A light guide into which the light of the semiconductor light emitting element is incident from the rear end surface;
A light-transmitting cover that is connected to an end of the housing and surrounds the light guide and diffuses light from the light guide;
The portion of the light guide surrounded by the light-transmitting cover has a plurality of light emitting portions in the central axis direction of the light guide,
A mounting table for fixing the light guide is provided at the end of the housing,
The translucent cover is formed with an insertion hole into which the light guide is inserted, a gap is provided around the light guide in the insertion hole, and the tip of the translucent cover is formed in a hemispherical shape. with that,
The light guide is composed of a single optical fiber,
The light emitting portion on the front end side of the portion surrounded by the light transmitting cover in the optical fiber is formed as a tapered portion whose diameter gradually decreases toward the tip, and the light transmitting cover in the optical fiber is formed. The light emitting portion on the rear end side of the portion surrounded by is formed as a reduced diameter portion having a concave shape over the entire circumference,
The sensitivity calibration light source device , wherein the tapered portion and the reduced diameter portion of the optical fiber have a core portion exposed by removing a clad layer . Wherein between the semiconductor light emitting element and the light guide of said rear end surface, according to claim 1, wherein the light incident hole having a smaller opening area than the area of the rear end face of the light guide is arranged Light source device for sensitivity calibration. 3. The sensitivity calibration light source device according to claim 2, wherein the mounting table is formed with an insertion hole that communicates with the light incident hole and fixes the proximal end side of the light guide. The light source device for sensitivity calibration according to any one of claims 1 to 3 , wherein the translucent cover is screwed to the mounting table. The semiconductor light emitting element is fixed on a base plate, a light detection element that receives light from the semiconductor light emitting element is fixed to the base plate, and the base plate is based on a signal from the light detection element. the semiconductor sensitivity calibration light source device according to any one of claim 1 to 4, characterized in that it is electrically connected to the control board for controlling the power supplied to the light emitting element.

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