JP2009238990A - Light source device - Google Patents

Light source device Download PDF

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Publication number
JP2009238990A
JP2009238990A JP2008082711A JP2008082711A JP2009238990A JP 2009238990 A JP2009238990 A JP 2009238990A JP 2008082711 A JP2008082711 A JP 2008082711A JP 2008082711 A JP2008082711 A JP 2008082711A JP 2009238990 A JP2009238990 A JP 2009238990A
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Japan
Prior art keywords
light
light source
direction
wavelength band
source device
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Pending
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JP2008082711A
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Japanese (ja)
Inventor
Atsushi Katsunuma
Hirohisa Ohira
淳 勝沼
博久 太平
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Nikon Corp
株式会社ニコン
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Application filed by Nikon Corp, 株式会社ニコン filed Critical Nikon Corp
Priority to JP2008082711A priority Critical patent/JP2009238990A/en
Publication of JP2009238990A publication Critical patent/JP2009238990A/en
Application status is Pending legal-status Critical

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Abstract

A white color which can align the position and shape of a light emitting part image in all light emission wavelength bands, and can prevent the emitted light from being separated into white light and having a colored pattern. A light source device is provided.
Light from an excitation LED 1 is collimated by a positive power optical system 2, and part of the light passes through a dichroic prism 3, is reflected by a plane mirror 6, and returns to the dichroic prism 3, and part of the light is reflected. It is reflected and output through the aperture stop 7. The light reflected by the dichroic prism 3 is collected by the positive power optical system 4 and forms an image of the excitation LED 1 on the phosphor 5. Thereby, the fluorescence generated from the phosphor 5 is collimated by the positive power optical system 4, passes through the dichroic prism 3, and is output through the aperture stop 7. Therefore, the aperture stop 7 outputs white light in which direct light and fluorescence are mixed.
[Selection] Figure 1

Description

  The present invention relates to a light source device.

  An example of a white LED according to the prior art is disclosed in Japanese Patent No. 3257455. As shown in FIG. 8, the schematic structure includes an LED light emitting unit 101 that emits excitation light, a substrate unit 103, and a phosphor 102. The phosphor 102 is in the form of a diffuser in which a fluorescent material is mixed in a transparent medium. Excitation light from the LED light emitting unit 101 diffuses by receiving a diffusing action inside the phosphor 102, and at the same time, fluorescence is emitted from the phosphor 102.

The wavelength of the excitation light from the LED light emitting unit 101 is in the visible short wavelength band such as blue or purple, or in the ultraviolet region close to the visible wavelength, and such excitation light and fluorescence having a wavelength in the longer wavelength band than that. Are combined with each other to produce white light.
Japanese Patent No. 3257455

  Such a white LED in the prior art is a surface light source that shines in an area larger than that of the original LED light emitting portion because the light emitting portion is the entire phosphor 102, and is made for a normal illumination light source.

  However, a part of the excitation light from the LED light emitting unit 101 and a part of the fluorescence from the fluorescent material are not synthesized with each other inside the phosphor 102, but from different positions on the surface of the phosphor 102. Radiates radially outward. For this reason, when the excitation light and fluorescence emitted from the surface of the phosphor 102 are received in the distance, the excitation light and fluorescence are largely separated, so that the light does not become white light but has a color pattern. There is a problem that there is.

  The present invention has been made in view of such circumstances, and the position and shape of the light-emitting portion image are aligned in all emission wavelength bands, and the emitted light is separated to have a color pattern without becoming white light. It is an object of the present invention to provide a white light source device that can prevent light from being emitted.

A light source that emits light having a first wavelength band;
The light from the light source enters from the first direction, divides the light into two, emits one of them as excitation light in the second direction, and the other as intermediate light in the third direction A first function that emits light; a second function that emits light having a second wavelength band that does not include the first wavelength band, incident from the second direction, in a fourth direction; A light splitting / combining element having a third function of combining the light having the first wavelength band incident from the direction of 3 with the light having the second wavelength band and emitting the light in the fourth direction When,
The excitation light emitted in the second direction from the light splitting / combining element emits fluorescence, and the generated fluorescence is emitted in a direction opposite to the excitation light, and the second light splitting / synthesizing element emits the second light. A phosphor incident from a direction;
A light source device comprising: a reflector that reflects the intermediate light emitted in the third direction from the light splitting and synthesizing element and makes the light splitting and synthesizing element incident again from the third direction. provide.

  According to the present invention, the position and shape of the light-emitting part image are aligned in all emission wavelength bands, and the emitted light is prevented from being separated into light with a color pattern without becoming white light. It is possible to provide a white light source device capable of

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an outline of a light source device which is an example of an embodiment of the present invention.

  The light beam (light having the first wavelength band) emitted from the excitation LED 1 as the light source is the first positive power optical system 2 (note that the power in the optical system is the reciprocal of the focal length. Power is the power (refractive power) of a positive focal length (for example, a convex lens), and negative power is the power of a negative focal length (for example, a concave lens). The light enters the dichroic prism 3 from the first direction (left side) of the dichroic prism 3 that is a splitting / combining element. A part of the light is reflected and the rest is transmitted. The reflected light becomes excitation light, and the transmitted light becomes intermediate light. That is, the light emitted from the light source is divided into excitation light and intermediate light by the dichroic prism 3.

  A typical example of the spectral characteristics of the dichroic prism 3 is shown in FIG. The horizontal axis is the wavelength λ, the vertical axis R is the reflectance, and the vertical axis T is the transmittance. A solid line indicates the reflectance, and a broken line indicates the transmittance.

  As shown in FIG. 2, the dichroic prism 3 transmits a part of the excitation light and reflects a part of the excitation light in the excitation light wavelength region E of the excitation LED 1. In this embodiment, the spectral characteristics of the dichroic prism 3 are set so that most components are transmitted in the fluorescence wavelength region F. In order for this embodiment to function efficiently, in the fluorescence wavelength region F, it is necessary to transmit at least 50% of light and reflect less than 50% of light. In the wavelength region F, it is particularly preferable that 70% or more of light is transmitted and less than 30% of light is reflected. As shown in FIG. 3, the excitation LED 1 includes a light emitting unit 11 and an electronic circuit board 12, and the area of the light emitting unit 11 is very small.

  As shown in FIG. 1, the excitation light beam reflected by the dichroic prism 3 is emitted from the second direction (upper side) of the dichroic prism 3 and is imaged by the second positive power optical system 4 on the light emitting unit 11 of the excitation LED 1. Form. As shown in FIG. 4, the phosphor 5 includes a phosphor film 51, a mirror 52, and a base 53. The fluorescent material film 51 is a thin film and is coated on the mirror 52. The base 53 holds the mirror 52 and the fluorescent material film 51. The phosphor 5 is placed on the surface of the phosphor material film 51 so that an image of the light emitting part 11 is formed.

  The portion of the fluorescent material film 51 where the image of the light emitting unit 11 is formed emits fluorescence (light having a second wavelength band not including the first wavelength band). Part of the fluorescence is reflected from the surface, and the other part is reflected by the mirror 52, passes through the fluorescent material film 51, and is emitted to the outside. The mirror 52 is not an essential component. Further, instead of the mirror 52, a reflector such as a prism sheet can be used. The fluorescent material film 51 is preferably provided in close contact with the mirror 52 from the viewpoint of making the fluorescent radiation portion a point light source.

  The fluorescent light beam from the phosphor 5 is collimated into a parallel light beam by the second positive power optical system 4 and enters the dichroic prism 3 from the second direction (upper side). The fluorescent parallel light beam passes through the dichroic prism 3 and is emitted from the fourth direction (lower side) of the dichroic prism 3.

  Of the luminous flux emitted from the excitation LED 1, the component (light source light) transmitted through the dichroic prism 3 is emitted from the third direction (right side) of the dichroic prism 3, reflected by the plane mirror 6, and again in the third direction. To the dichroic prism 3. Then, a part of the light passes through the dichroic prism 3 and returns to the light source side, but the rest is reflected by the dichroic prism 3 and is mixed with the fluorescent parallel light flux as light having the same wavelength band as the light source light. The light is emitted as white light from the fourth direction (lower side) of the dichroic prism 3. This becomes the output light.

  Since the aperture stop 7 is provided, the fluorescent light beam and the light reflected by the dichroic prism 3 are output by the aperture stop 7 with the same light beam diameter. That is, the fluorescence and the light source light are synthesized and output by the dichroic prism 3 which is a light splitting / synthesizing element.

  FIG. 6 shows typical examples of the spectral characteristics of the light emitting component, the fluorescent spectral characteristics, and the spectral characteristics of the output light of the excitation LED 1. The horizontal axis represents wavelength, and the vertical axis P represents optical power. The broken line is the spectral characteristic of the light emitting component of the excitation LED 1, the alternate long and short dash line is the spectral characteristic of fluorescence, and the solid line is the spectral characteristic of output light. It can be seen that the output light has a spectral component over a wide wavelength range and is white light.

  The output light is designed to have a desired spectral characteristic by selecting the direct emission wavelength from the excitation LED 1, adjusting the emission spectral characteristic by selective preparation of the fluorescent material, and designing the spectral characteristic of the dichroic prism 3. In particular, the output light wavelength range is adjusted to the visible range, and the spectral characteristics are balanced to provide a visible range white light source.

  When the light source is viewed through the aperture stop 7, the image of the light emitting portion 11 of the excitation LED 1 and the fluorescent light source image formed on the fluorescent material film 51 almost coincide with each other, and function as if they are the same light source. Further, since the excitation light beam diameter and the fluorescent light beam diameter also coincide, it becomes a light source equivalent to a single white light source.

  Accordingly, the light emitted from the excitation LED 1 and the light emitted from the fluorescent material film 51 are not separated even at a long distance, and the light having a color pattern that is possible in the prior art is not produced. This is because the first positive power optical system 2 and the second positive power optical system 4 make the light emitting part 11 image of the excitation LED 1 and the fluorescent light source image formed on the fluorescent material film 51 almost coincide with each other, and the first positive power optical system 2 and the second positive power optical system 4. This is because the light beams emitted from the optical system 2 and the second positive power optical system 4 are converted into parallel light beams. In addition, since both the light emitting part 11 image of the excitation LED 1 and the fluorescent light source image formed on the fluorescent material film 51 have a very small area, a sufficient amount of light can be incident even when entering an optical fiber having a small NA. Even when used as a light source for a spectroscope, the light source can be handled as a point light source.

  When the light beam (having a wavelength band component of the light source light) emitted from the fourth direction (lower side) reflected by the dichroic prism 3 and the fluorescent parallel light beam substantially coincide with each other, The aperture stop 7 is not necessarily provided.

  According to the present embodiment, the excitation light source and the fluorescence light source can be apparently set in the same shape and at the same position, and the size of the common light source can be limited to the size of the LED light emitting unit that is the excitation light source. . As a result, the light emitting part image of the excitation LED 1 is almost the same size, so that it is possible to realize a continuous spectrum white light source that is compatible with a device that requires a light emitting part as small as possible, such as a spectroscope or a single-line optical fiber.

  In addition, it has the effect of adjusting the emission spectrum balance by designing the spectral characteristics of the dichroic prism as well as determining the emission spectrum by adjusting the emission wavelength of the light source LED and the composition of the phosphor as in the case of a normal white LED. is there.

  In the above embodiment, the excitation LED 1 is used as the light source, and the light emitted from the light source is emitted radially, so that the first positive power optical system 2 is used in order to make it parallel light. Yes. However, when a light source that emits parallel light, such as a laser, is used as the light source, it is not necessary to use the first positive power optical system 2, and if the parallel light beam from the light source simply enters the dichroic prism 3. Good.

  1 may be placed on the right side of the dichroic prism 3 and the flat mirror 6 may be placed on the upper side of the dichroic prism 3. In this case, the right side of the dichroic prism 3 is the second direction, and the upper side is the third direction. In this case, the dichroic prism 3 is designed so that most of the light is reflected in the region (fluorescent region) indicated by F in FIG. 4 of the dichroic prism 3.

  In this way, the fluorescent light beam emitted from the phosphor enters the dichroic prism 3 from the right side (second direction) of the dichroic prism 3, is reflected by the dichroic prism 3, and is below the dichroic prism 3 (fourth). From the direction). Further, a part of the light (light having the first wavelength band) that is reflected by the plane mirror 6 and is incident on the dichroic prism 3 again from the upper side (third direction) of the dichroic prism 3 is reflected by the dichroic prism 3. However, the remaining light passes through the dichroic prism 3 and is mixed with the fluorescent parallel light beam as light having a component in the same wavelength band as that of the light source light, and the lower side of the dichroic prism 3 (fourth). From the direction of the white light). This becomes the output light. The fact that such a configuration is effectively equivalent to the embodiment shown in FIG. 1 will not require further explanation.

  FIG. 5 is a diagram showing an outline of a light source device as another example of the embodiment of the present invention. The embodiment shown in FIG. 5 is obtained by replacing the dichroic prism 3 of the embodiment shown in FIG. 1 with a dichroic mirror 3 ′, and the configuration of other parts is exactly the same as FIG. 1.

  If the characteristics of the dichroic mirror 3 ′ are made the same as the characteristics of the dichroic prism 3, it is possible to obtain exactly the same functions and effects as those of the optical device shown in FIG. 1. The description of the operational effect is omitted because it overlaps with the description of FIG.

It is a figure which shows the outline | summary of the light source device which is an example of embodiment of this invention. It is a figure which shows the typical example of the spectral characteristic of a dichroic prism. It is a figure which shows the detail of excitation LED. It is a figure which shows the detail of fluorescent substance. It is a figure which shows the outline | summary of the light source device which is other of embodiment of this invention. It is a figure which shows the typical example of the spectral characteristic of the light emission component of excitation LED, the spectral characteristic of fluorescence, and the spectral characteristic of output light. It is a figure which shows the example of the structure of the conventional white LED.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Excitation LED, 2 ... 1st positive power optical system, 3 ... 1st dichroic prism, 3 '... Dichroic mirror, 4 ... 2nd positive power optical system, 5 ... Phosphor, 6 ... 1st plane mirror, 7 ... Aperture stop, 11 ... light emitting portion, 12 ... electronic circuit board, 51 ... fluorescent material film, 52 ... mirror, 53 ... base

Claims (12)

  1. A light source that emits light having a first wavelength band;
    The light from the light source enters from the first direction, divides the light into two, emits one of them as excitation light in the second direction, and the other as intermediate light in the third direction A first function that emits light; a second function that emits light having a second wavelength band that does not include the first wavelength band, incident from the second direction, in a fourth direction; A light splitting / combining element having a third function of combining the light having the first wavelength band incident from the direction of 3 with the light having the second wavelength band and emitting the light in the fourth direction When,
    The excitation light emitted in the second direction from the light splitting / combining element emits fluorescence, and the generated fluorescence is emitted in a direction opposite to the excitation light, and the second light splitting / synthesizing element emits the second light. A phosphor incident from a direction;
    A light source device comprising: a reflector that reflects the intermediate light emitted in the third direction from the light splitting and synthesizing element, and again enters the light splitting and synthesizing element from the third direction.
  2.   The light splitting / synthesizing element reflects the part of the light from the light source to be the excitation light, transmits the rest to be the intermediate light, and enters the second wavelength band from the second direction. Transmitting most of the light having the first wavelength band, reflecting most of the light having the first wavelength band, and transmitting a part of the light having the first wavelength band incident from the third direction. The light source device according to claim 1, wherein the light source device is a dichroic mirror or a dichroic prism that reflects the rest.
  3.   The light source device according to claim 1, wherein a transmittance of the light splitting / combining element with respect to the second wavelength band is larger than a transmittance with respect to the first wavelength band.
  4.   The light splitting / synthesizing element transmits the part of the light from the light source to be the excitation light, reflects the rest to be the intermediate light, and is incident from the second direction. Reflecting most of the light having the first wavelength band and transmitting most of the light having the first wavelength band, and transmitting a part of the light having the first wavelength band incident from the third direction. The light source device according to claim 1, wherein the light source device is a dichroic mirror or a dichroic prism that reflects the rest.
  5.   5. The light source device according to claim 1, wherein a transmittance of the light splitting and synthesizing element with respect to the second wavelength band is smaller than a transmittance with respect to the first wavelength band.
  6.   6. The apparatus according to claim 1, further comprising a first positive power optical system having a positive power disposed between the light source and the light splitting / combining element. 7. Light source device.
  7.   7. The apparatus according to claim 1, further comprising a second positive power optical system having a positive power disposed between the phosphor and the light splitting / combining element. Light source device.
  8.   The light source device according to claim 1, wherein the light source emits the light radially.
  9.   The light source device according to claim 1, wherein the light source emits the light as a parallel light flux.
  10.   10. The apparatus according to claim 1, further comprising an opening that allows light in a central portion of the light synthesized by the light splitting and synthesizing element to pass therethrough and shields light in a peripheral portion. Light source device.
  11.   The light source device according to any one of claims 1 to 10, wherein the phosphor includes a phosphor film and a reflector.
  12.   The light source device according to claim 11, wherein the fluorescent material film is in close contact with the reflector.
JP2008082711A 2008-03-27 2008-03-27 Light source device Pending JP2009238990A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2008082711A JP2009238990A (en) 2008-03-27 2008-03-27 Light source device

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Application Number Priority Date Filing Date Title
JP2008082711A JP2009238990A (en) 2008-03-27 2008-03-27 Light source device

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JP2009238990A true JP2009238990A (en) 2009-10-15

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012002542A1 (en) * 2010-07-01 2012-01-05 株式会社ニコン Optical members and microscope
JP2012037681A (en) * 2010-08-06 2012-02-23 Casio Comput Co Ltd Light source unit and projector

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2012002542A1 (en) * 2010-07-01 2012-01-05 株式会社ニコン Optical members and microscope
US8773761B2 (en) 2010-07-01 2014-07-08 Nikon Corporation Optical member and microscope
JP5673679B2 (en) * 2010-07-01 2015-02-18 株式会社ニコン Microscope
JP2012037681A (en) * 2010-08-06 2012-02-23 Casio Comput Co Ltd Light source unit and projector

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