Abstract:
The optical component according to the present invention includes a fixed member including a through hole, and a wavelength conversion member having at least one part thereof arranged in the through hole, where the fixed member is formed with a cut-in part or a hole part in a direction substantially perpendicular to the longitudinal direction of the through hole.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an optical component including a wavelength conversion member for wavelength converting the light from a light source. 
         [0003]    2. Description of the Related Art 
         [0004]    Conventionally, a light source is proposed that transmits the light from the light source to a disperser via a separator such as an optical fiber to disperse the light into a desired pattern or change the color of the light (see Japanese Laid-Open Patent Publication No. 2003-515899). 
         [0005]    A can package in which the semiconductor laser element is hermetically sealed is also known. The can package is hermetically sealed by a stem mounted with the semiconductor laser element and a cap having a constant thickness. A glass window for extracting the laser light is formed in the cap, and the glass is fixed to the inner side of the cap by way of resin adhesive. 
       SUMMARY OF THE INVENTION 
       [0006]    However, the conventional light source merely has a disperser attached to the distal end of the separator such as an optical fiber, and thus the light emitting efficiency may not be satisfactory depending on the attaching method, and more improvement is required to be used as an optical component capable of being attached to the end part of the optical fiber. 
         [0007]    As for the can package, the glass is fixed with resin adhesive, and thus organic components are volatilized from the resin adhesive. Such organic components become impurities and attach to the inside of the can package, in particular, to the glass and the exit end part of the semiconductor laser element, thereby lowering the optical output of the laser light. 
         [0008]    It is, therefore, an object of the present invention to provide an optical component that has a simple configuration and that prevents lowering of the optical output. 
         [0009]    According to the present invention, such aim is accomplished in the following manner. 
         [0010]    The optical component according to the present invention includes a fixed member including a through hole; and a wavelength conversion member having at least one part arranged in the through hole; where the fixed member is formed with a cut-in part or a hole part in a direction substantially perpendicular to the longitudinal direction of the through hole. A configuration that is simple and that prevents lowering in optical output is thereby achieved. 
         [0011]    The wavelength conversion member is preferably fixed to the fixed member using a fixing member. Therefore, the wavelength conversion member can be reliably fixed to the fixed member. Furthermore, hermetic sealing is realized. 
         [0012]    The fixing member is preferably a low melting point glass. In particular, the low melting point glass having a softening point at lower than or equal to 650° C. is preferable. Degradation of the optical component can be thereby suppressed. 
         [0013]    The fixing member is preferably filled in the cut-in part or the hole part formed in the fixed member when fixing the wavelength conversion member to the fixed member using the fixing member. Accordingly, the attachment of the wavelength conversion member to the fixed member is reliably performed with a small amount of fixing member, and thus lowering in optical output due to light absorption by the fixing member can be suppressed. 
         [0014]    In addition to the above configuration, the fixed member may include a projection or a concave part for fitting the wavelength conversion member at the through hole side. When the fixed member has a projection on the through hole side, the wavelength conversion member preferably has a concave part that mates with the projection, or when the fixed member has a concave part on the through hole side, the wavelength conversion member preferably has a projection that fits into the concave part. With this configuration, the wavelength conversion member can be fixed even more reliably. 
         [0015]    Preferably, the fixed member is a tubular body with its inner hole being circular in a transverse cross section. Chips and cracks of the fixed member can be thereby prevented. 
         [0016]    The fixed member preferably includes a step at the through hole. The wavelength conversion member is thereby positioned at the step portion of the fixed member, and thus can always be arranged at a constant position. 
         [0017]    The fixed member preferably has a diameter of at least one part of the through hole the same as or greater than a diameter of the wavelength conversion member. The detachment of the wavelength conversion member from the fixed member is thus less likely to occur. 
         [0018]    The wavelength conversion member is preferably fitted in the through hole of the fixed member. The foreign substances are thus prevented from entering into the through hole. 
         [0019]    The wavelength conversion member is preferably obtained by mixing a fluorescent material in glass. Degradation of the wavelength conversion member can be thereby prevented. 
         [0020]    The glass is preferably silicate glass. In particular, silicate glass containing one or more types of alkali metal oxide, alkali earth metal oxide, boron oxide, phosphorus oxide, zinc oxide is preferable. The resistance to weather of the wavelength conversion member thereby enhances, and degradation of the wavelength conversion member can be prevented. 
         [0021]    According to the present invention, an optical component that has a simple configuration and that prevents lowering of optical output is achieved. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a view showing a configuration of an optical component according to a first embodiment of the present invention; 
           [0023]      FIG. 2  is a view showing a configuration of an optical component according to a second embodiment of the present invention; 
           [0024]      FIG. 3  is a view showing a configuration of an optical component of a comparative example in which a fixing member is arranged on the side surface of the waveform conversion member; 
           [0025]      FIG. 4  is a view showing a configuration of a light emitting device equipped with the optical component according to the first embodiment of the present invention; 
           [0026]      FIG. 5  is a view showing a configuration of another light emitting device equipped with the optical component according to the first embodiment of the present invention; 
           [0027]      FIG. 6  is a view showing a light emitting device used in evaluating the optical component according to a first example of the present invention; and 
           [0028]      FIG. 7  is a view showing the effects of the first example of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0029]    The preferred embodiments according to the present invention will now be described in detail with reference to the accompanying drawings. 
         [0030]      FIG. 1  is a view showing a configuration of an optical component according to a first embodiment of the present invention. 
         [0031]    As shown in  FIG. 1 , the optical component according to the first embodiment includes a fixed member  1  and a wavelength conversion member  2 . The fixed member  1  includes a fit-in part  3 - 2  in which the wavelength conversion member  2  is fitted, and a through hole  3 - 1  that contacts the fit-in part  3 - 2  with a step  4  in between. The outer shape of the fixed member  1  may be any shape such as circular, rectangular, and elliptical as long as it is a tubular body, but is preferably circular. The transverse cross sectional shape of an inner hole part of the tubular body, or the through hole  3 - 1  and the fit-in part  3 - 2 , may be any shape such as circular, rectangular, and elliptical, but is preferably circular. The wavelength conversion member  2  may be of any shape such as column, quadratic prism, elliptic cylinder, sphere, hemisphere etc., but is preferably a column. The wavelength conversion member  2  is arranged in the fit-in part  3 - 2  of the fixed member  1 , and is fixed to the fixed member  1  by filling a cut-in part  5 - 1  formed at the side surface of the fit-in part  3 - 2  with the fixing member  5 - 2 . Any number of cut-in parts  5 - 1  may be formed, but is preferably equally arranged at the periphery of the wavelength conversion member  2 . 
         [0032]    The fixing method of the fixed member  1  and the wavelength conversion member  2  is that the wavelength conversion member  2  is fixed to the fixed member  1  by pushing the fixing member (low melting point glass)  5 - 2 , which is molded so as to comply with the shape of the cut-in part in advance, onto the cut-in part  5 - 1  with the wavelength conversion member  2  arranged in the fit-in part  3 - 2  of the fixed member  1 , and performing heating in this state to fill the fixing member  5 - 2  in the cut-in part  5 - 1 . 
         [0033]    The material of the fixed member  1  is preferably a material that has an anti-corrosion property and that easily adheres to the low melting point glass, and stainless material may be used. 
         [0034]    According to the first embodiment, the attachment of the wavelength conversion member  2  to the fixed member  1  is reliably performed with the fixing member  5 - 2  of a smaller amount than in the attaching method (see  FIG. 3 ) in which the low melting point glass is arranged on the side surface of the wavelength conversion member, and thus the affect of the fixing member  5 - 2  on properties such as light absorption is small. Therefore, according to the first embodiment, the light that exits from the wavelength conversion member  2  is discharged without being attenuated, thereby improving the light emitting efficiency. 
         [0035]      FIG. 2  is a view showing a configuration of an optical component according to a second embodiment of the present invention. 
         [0036]    As shown in  FIG. 2 , the optical component according to the second embodiment includes a fixed member  1  and a wavelength conversion member  2 . The fixed member  1  includes a fit-in part  3 - 2  in which the wavelength conversion member  2  is fitted, and a through hole  3 - 1  that contacts the fit-in part  3 - 2  with a step  4  in between. The outer shape of the fixed member  1  may be any shape such as circular, rectangular, and elliptical as long as it is a tubular body, but is preferably circular. The transverse cross sectional shape of an inner hole part of the tubular body, or the through hole  3 - 1  and the fit-in part  3 - 2 , may be any shape such as circular, rectangular, and elliptical, but is preferably circular. The wavelength conversion member  2  may be of any shape such as column, quadratic prism, elliptic cylinder, sphere, and hemisphere, but is preferably a column. The wavelength conversion member  2  is arranged in the fit-in part  3 - 2  of the fixed member  1 , and is fixed to the fixed member  1  by filling a hole part  6 - 1  formed at the side surface of the fit-in part  3 - 2  with the fixing member  6 - 2 . Any number of hole parts  6 - 1  may be formed, but is preferably equally arranged at the periphery of the wavelength conversion member  2 . 
         [0037]    The fixing method of the fixed member  1  and the wavelength conversion member  2  is that the wavelength conversion member  2  is fixed to the fixed member  1  by filling the granulated low melting point glass  6 - 2  serving as the fixing member into the hole part  6 - 1  with the wavelength conversion member  2  arranged in the fit-in part  3 - 2  of the fixed member  1 , and performing heating in this state. 
         [0038]    According to the second embodiment, the attachment of the wavelength conversion member  2  to the fixed member  1  is reliably performed with a small amount of fixing member  6 - 2 , and thus the affect of the fixing member  6 - 2  on properties such as light absorption is small. Therefore, according to the second embodiment, the light that exits from the wavelength conversion member  2  is discharged without being attenuated, thereby improving the light emitting efficiency. 
         [0039]      FIG. 3  is a view showing a configuration of an optical component of a comparative example through an attaching method in which the fixing member is arranged on the side surface of the wavelength conversion member. 
         [0040]    As shown in  FIG. 3 , the optical component with the low melting point glass arranged on the side surface of the wavelength conversion member includes a fixed member  1  and a wavelength conversion member  2 . The fixed member  1  includes a fit-in part  3 - 2  in which the wavelength conversion member  2  is fitted, and a through hole  3 - 1  that contacts the fit-in part  3 - 2  with a step  4  in between, but differs from the optical components shown in  FIGS. 1 and 2  in that a cut-in part nor a hole part is formed at the side surface of the fit-in part  3 - 2 . The fixed member  1  is a tubular body having a circular inner hole. The wavelength conversion member  2  has a columnar shape. The fixing method of the fixed member  1  and the wavelength conversion member  2  is that the wavelength conversion member  2  is fixed to the fixed member  1  by inserting the low melting point glass  6 - 3  molded into a ring shape in the wavelength conversion member  2  with the wavelength conversion member  2  arranged in the fit-in part  3 - 2  of the fixed member  1 , and performing heating in this state. 
         [0041]    In the optical component shown in  FIG. 3 , the fixed member  1  and the wavelength conversion member  2  cannot be fixed with a small amount of fixing member  6 - 3  since the cut-in part nor the hole part is formed at the side surface of the fit-in part  3 - 2  of the fixed member  1 , and the fixing member  6 - 3  must be arranged around the entire periphery of the wavelength conversion member  2 . Thus, the fixed portion of the fixed member  1  and the wavelength conversion member  2  has a shape in which the low melting point glass is arranged at the side surface of the wavelength conversion member. In this case, some of the light that exits from the wavelength conversion member  2  is absorbed by the fixing member  6 - 3  and shielded, whereby the light emitting efficiently lowers. 
         [0042]      FIG. 4  is a view showing a configuration of a light emitting device equipped with the optical component according to the first embodiment of the present invention. 
         [0043]    The light emitting device shown in  FIG. 4  has a mounting platform  7  fixed to the through hole  3 - 1  side arranged opposite the fit-in part  3 - 2 , which is fitted with the wavelength conversion member  2 , of the fixed member  1  by way of a joining part  9 . The fixing method includes weld fixation, fixing agent fixation, and brazing. A light source  8  is arranged on the mounting platform  7 , and is arranged at a position where the light that exits from the light source  8  is efficiently guided to the wavelength conversion member. 
         [0044]    The attachment of the wavelength conversion member  2  to the fixed member  1  is reliably performed with a small amount of fixing member  5 - 2 , and thus none of the fixing member  5 - 2  goes around to the through hole  3 - 1  side, and properties such as light absorption will not be affected. Therefore, the light that exits from the light source  8  is guided to the wavelength conversion member  2  without being attenuated, and the light emitting efficiency can be improved. The light source  8  emits light having a light emission peak within the wavelength region of 300 nm to 500 nm, and a light emitting diode, a semiconductor laser element etc. is used as the light source. 
         [0045]      FIG. 5  is a view showing a configuration of another light emitting device equipped with the optical component according to the first embodiment of the present invention. 
         [0046]    The light emitting device shown in  FIG. 5  has a light guide holding member  11  arranged with a light guide  10  fixed to the through hole  3 - 1  side arranged opposite the fit-in part  3 - 2 , which is fitted with the wavelength conversion member  2 , of the fixed member  1  by way of a joining part  12  arranged on the side surface of the fixed member  1 . The fixing method includes weld fixation and fixing agent fixation. 
         [0047]    In weld fixation, the fixed member  1  and the light guide holding member  11  can be weld fixed through, e.g. YAG laser welding. In YAG laser welding, the YAG laser is irradiated onto the fixed member  1  to melt the fixed member  1 , thereby weld fixing the fixed member  1  and the light guide holding member  11 . Therefore, the portion weld fixed by the YAG welding becomes the joining part  12 . 
         [0048]    In fixing agent fixation, a hole is formed at the side surface of the fixed member  1  in advance, and after the light guide holding member  11  is inserted into the through hole  3 - 1 , the fixing material is filled into the hole formed at the side surface of the fixed member  1 , thereby fixing with fixing agent the fixed member  1  and the light guide holding member  11 . Therefore, the portion fixed by the fixing material becomes the joining part  12 . 
         [0049]    The attachment of the wavelength conversion member  2  to the fixed member  1  is reliably performed with a small amount of fixing member  5 - 2 , and thus none of the fixing member  5 - 2  goes around to the through hole  3 - 1  side, and the light guide  10  can be brought closer to the wavelength conversion member  2 . Therefore, the light that exits from the light guide  10  is guided to the wavelength conversion member  2  without being attenuated, thereby improving the light emitting efficiency. 
         [0050]    The glass used for the wavelength conversion member is preferably silicate glass. In particular, silicate glass containing one or more types of alkali metal oxide, alkali earth metal oxide, boron oxide, phosphorus oxide, zinc oxide is preferable. The wavelength conversion member is obtained by mixing fluorescent material powder and glass powder, and performing e.g. heat press molding on the mixed powder. 
         [0051]    The fixing material is preferably the low melting point glass having a softening point at lower than or equal to 650° C. 
       EXAMPLE 
       [0052]      FIG. 6  is a view showing a light emitting device used in evaluating the optical component according to a first example of the present invention. 
         [0053]    In the first example, the transverse cross sectional shape of the fixed member  1 , the through hole  3 - 1  and the fit-in part  3 - 2  is circular. The outer diameter of the fixed member  1  is 1.25 mm, the inner diameter of the through hole  3 - 1  is 0.7 mm, and the inner diameter of the fit-in part  3 - 2  is 0.9 mm. The depth of the fit-in part  3 - 2  is 0.1 mm, and the size of the cut-in part  5 - 1  is 0.2 mm in radius and 0.1 mm in depth and is arranged at two locations at opposite angles at the side surface of the fit-in part  3 - 2 . The wavelength conversion member  2  also has a columnar shape having a diameter of 0.9 mm and a thickness of 0.45 mm. The wavelength conversion member  2  is fitted in the fit-in part  3 - 2 , and is fixed by filling the fixing member  5 - 2  to the cut-in part  5 - 1 . The material of the fixing member  5 - 2  used for fixing is the low melting point glass having a softening point at 520° C., and is filled by 0.07 mg. The light guide holding member  11  arranged with the light guide  10  is inserted into the through hole  3 - 1  of the fixed member  1 , and is fixed by a fixing part  13 . YAG laser welding is used for fixing. 
         [0054]      FIG. 7  shows the output characteristic of the light that exits from the wavelength conversion member  2  when the laser light of about 445 nm is entered from the incident side of the light guide  10 . This is compared with the optical output characteristic of a sample having a shape in which the low melting point glass is arranged on the side surface of the wavelength conversion member as shown in  FIG. 3  without using the present invention. As a result, the increase by approximately 1.3 times in light emitting efficiency is achieved by the present invention. 
         [0055]    The present invention can be used in light emitting devices such as light emitting diode and semiconductor laser element.