JP2010079013A - Manufacturing process of optical member, and optical member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing process for facilitating equalization of spectral reflectance when manufacturing an optical member, and to provide an optical member having such a structure that an optical member uniform in spectral reflectance can be easily manufactured. <P>SOLUTION: In a manufacturing method of a lens 1 which has a plurality of layers of films disposed on a surface thereof to form an anti-reflection film 3, the number of layers of films is set to 7 to 9, and an arrangement condition of films is so adjusted that the anti-reflection film 3 has a band width zone keeping a spectral reflectance of ≤2% in a band of 400 to 750 nm, that the spectral reflectance gradually increases in the bandwidth zone in accordance with the increase of wavelength to have a peak value, and that the anti-reflection film 3 has two or three spectral reflectance peak value holding zones wherein the spectral reflectance gradually decreases from the peak value in accordance with the further increase of wavelength. The arrangement condition of films is adjusted in this manner to obtain the lens 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for manufacturing an optical member and an optical member.

  In general, when the wavelength of visible light is in the range of 400 nm to 700 nm, the spectral reflectance at a wavelength in the range of 450 nm to 650 nm, which is a relatively high sensitivity of the human eye, is 1% or less, and more preferably 0.8%. An antireflective material intended to be 5% or less has been proposed (see Patent Document 1). The antireflective material described in Patent Document 1 is formed by alternately laminating silica layers and titania layers to form a total of four layers.

JP 2002-122705 A

  However, in the antireflection material described in Patent Document 1, it may be difficult to obtain the target spectral reflectance depending on the film forming conditions and the like.

  Accordingly, an object of the present invention is to provide an optical member manufacturing method that facilitates uniform spectral reflectance in manufacturing an optical member, and an optical member having a configuration that facilitates manufacturing an optical member having uniform spectral reflectance. Is to provide.

  In order to achieve the above object, the method for producing an optical member of the present invention is a method for producing an optical member in which a plurality of layers are disposed on the surface to form an antireflection film. The antireflection film has a bandwidth that maintains a spectral reflectance of 2% or less in the band from 400 to 750 nm, and the spectral reflectance gradually increases as the wavelength increases in the bandwidth band. The film arrangement conditions are adjusted so as to have two or three spectral reflectance peak value bands where the spectral reflectance gradually decreases from the peak value as the wavelength increases and the wavelength increases.

  In order to achieve the above object, the method for producing an optical member of the present invention is a method for producing an optical member in which a plurality of layers are arranged on the surface to form an antireflection film. The antireflection film has a bandwidth that maintains a spectral reflectance of 2% or less in the band from 400 to 750 nm, and the spectral reflectance gradually increases as the wavelength increases in the bandwidth band. As the wavelength increases, the spectral reflectance gradually decreases from the peak value as the wavelength increases, so that there are two to four spectral reflectance peak holding bands, and the bandwidth of the peak holding band The film arrangement conditions are adjusted so that the minimum value is equal to or greater than the value of “(350 nm / x) /1.6” where x is the number of peak value holding bands.

  Here, the adjustment of the arrangement condition is preferably the adjustment of the thickness of the film.

  Moreover, it is preferable that one of the peak values exists between wavelengths of 600 to 650 nm.

  In order to achieve the above object, the optical member of the present invention includes an antireflection film comprising a plurality of layers on the surface, and the number of antireflection films is 7 to 9, and the antireflection film However, the spectral reflectance gradually increases and the peak value appears as the wavelength increases in the bandwidth of 400 to 750 nm so that the spectral reflectance is 2% or less. There are two or three spectral reflectance peak value holding bands in which the spectral reflectance gradually decreases from the peak value as the wavelength increases.

  In order to achieve the above object, the optical member of the present invention comprises an antireflection film comprising a plurality of layers on the surface, wherein the number of antireflection films is 7 to 11, and the antireflection film However, the spectral reflectance gradually increases and the peak value appears as the wavelength increases in the bandwidth of 400 to 750 nm so that the spectral reflectance is 2% or less. As the wavelength increases, the spectral reflectance gradually decreases from the peak value as the wavelength increases. There are two to four spectral reflectance peak value holding bands, and the minimum bandwidth of the peak value holding band is the peak value. When the number of retained bands is x, the value is equal to or greater than “(350 nm / x) /1.6”.

  Here, it is preferable to set the peak value holding band to two and the peak value to a wavelength other than the wavelength of 490 to 575 nm which becomes green.

  According to the present invention, in manufacturing an optical member, it is possible to provide a method for manufacturing an optical member that facilitates uniform spectral reflectance, and to provide an optical member that has a configuration that facilitates manufacturing an optical member having uniform spectral reflectance. it can.

  The manufacturing method of the optical member which concerns on embodiment of this invention is a manufacturing method of the optical member which arrange | positions the film | membrane of multiple layers on the surface, and forms an antireflection film. In this method of manufacturing an optical member, the number of film layers is 7 to 9. The antireflection film has a bandwidth that maintains a spectral reflectance of 2% or less in a band from 400 to 750 nm. The spectral reflectance gradually increases and the peak value appears as the wavelength increases in that bandwidth, and the spectral reflectance gradually decreases from the peak value as the wavelength further increases. The arrangement condition of the film is adjusted so as to have two or three zones.

  Moreover, the manufacturing method of the optical member which concerns on embodiment of this invention is a manufacturing method of the optical member which arrange | positions the film | membrane of multiple layers on the surface, and forms an antireflection film. In this method of manufacturing an optical member, the number of film layers is 7 to 11. The antireflection film has a bandwidth that maintains a spectral reflectance of 2% or less in a band from 400 to 750 nm. The spectral reflectance gradually increases and the peak value appears as the wavelength increases in that bandwidth, and the spectral reflectance gradually decreases from the peak value as the wavelength further increases. There are two to four bands. Further, the film arrangement condition is adjusted so that the minimum value of the peak value holding band is equal to or more than “(350 nm / x) /1.6” where x is the number of peak value holding bands. ing.

  Here, the adjustment of the arrangement condition is the adjustment of the thickness of the film. In addition, one of the peak values exists between wavelengths of 600 to 650 nm.

  An optical member according to an embodiment of the present invention is an optical member that includes an antireflection film including a plurality of layers on the surface. The number of antireflection film layers is 7 to 9. The antireflection film has a bandwidth band in which the spectral reflectance is 2% or less in the band from 400 to 750 nm. The spectral reflectance gradually increases and the peak value appears as the wavelength increases in that bandwidth, and the spectral reflectance gradually decreases from the peak value as the wavelength further increases. It has two or three bands.

  Moreover, the optical member according to the embodiment of the present invention includes an antireflection film composed of a plurality of layers on the surface. The number of antireflection films is 7 to 11. The antireflection film has a bandwidth band in which the spectral reflectance is 2% or less in the band from 400 to 750 nm. The spectral reflectance gradually increases and the peak value appears as the wavelength increases in that bandwidth, and the spectral reflectance gradually decreases from the peak value as the wavelength further increases. There are two to four bands. The minimum value of the bandwidth of the peak value holding band is equal to or more than the value “(350 nm / x) /1.6” where x is the number of peak value holding bands.

  Here, two peak value holding bands are set, and the peak value is set to a wavelength other than the wavelength of 490 to 575 nm which becomes green.

  Hereinafter, a schematic configuration of a lens as an optical member according to an embodiment of the present invention and a method for manufacturing the lens will be described with reference to the drawings with specific examples.

(Schematic configuration of the lens according to the first embodiment)
FIG. 1 is a longitudinal sectional view showing a schematic configuration of a lens 1 according to a first embodiment of the present invention. The lens 1 includes a lens body 2 made of glass, and an alumina layer 3A having an antireflection effect made of aluminum oxide (Al ₂ O ₃ ) disposed on the surface of the lens body 2. The lens 1 further includes a mixed layer 3B1 in which titanium oxide (TiO ₂ ) and zirconium oxide (ZrO ₂ ) are mixed on the upper surface of the alumina layer 3A in FIG. 1 and has an antireflection effect, and the mixed layer 3B1 in FIG. A magnesium layer 3C1 made of magnesium fluoride (MgF ₂ ) and having an antireflection effect is provided on the upper surface. Further, on the upper surface of FIG. 1 of this magnesium layer 3C1, two mixed layers 3B2 and 3B3 having the same component as the mixed layer 3B1 and two magnesium layers 3C2 and 3C3 having the same component as the magnesium layer 3C1 are alternately stacked. Yes. As a result, the number of layers of the antireflection film 3 of the lens 1 is seven.

  That is, in the lens 1, the layers are laminated in the order of the alumina layer 3A, the mixed layer 3B1, the magnesium layer 3C1, the mixed layer 3B2, the magnesium layer 3C2, the mixed layer 3B3, and the magnesium layer 3C3 in the upward direction in FIG. ing. The total physical film thickness of these seven layers is 300 nm.

  Hereinafter, when referring to the whole of the seven-layer antireflection film 3, it is referred to as an antireflection film 3. Moreover, when referring to the whole of the mixed layers 3B1, 3B2, and 3B3, the mixed layer 3B is described. Moreover, when referring to the whole of the magnesium layers 3C1, 3C2, 3C3, it is described as the magnesium layer 3C.

  In FIG. 2, the thickness of each layer which comprises the antireflection film 3 is shown. This film thickness is shown as an optical film thickness (λ / 4 = 0.25) (the same applies to FIGS. 5, 6 and 7 below). The optical film thickness λ is the center wavelength used when the antireflection film 3 is designed. In the lens 1, “λ = 510 nm” is set. The optical film thickness has a relationship of (n × d) / λ where n is the refractive index and d is the physical film thickness. Here, the refractive index of the alumina layer 3A is 1.63, the refractive index of the mixed layer 3B is 2.1, and the refractive index of the magnesium layer 3C is 1.38. The refractive index of the lens body 2 is 1.52. Then, the physical thickness of the alumina layer 3A is 22.84 nm, the physical thickness of the mixed layer 3B1 is 17.49 nm, and the physical thickness of the magnesium layer 3C1 is 29.93 nm. Note that, depending on the number of significant digits of the refractive index value, some values may vary in the calculation.

  Among the layers of the antireflection film 3, the magnesium layer 3C3 is the thickest. The next thicker layer is the mixed layer 3B2. The next thickest layer is the mixed layer 3B3. The other layers are less than half the thickness of the mixed layer 3B3, and the thickness decreases in the order of the mixed layer 3B1, the alumina layer 3A, the mixed layer 3B1, and the magnesium layer 3C2.

  FIG. 3 shows changes in the spectral reflectance with respect to the wavelength of the lens 1. The lens 1 has a bandwidth band in which the spectral reflectance is maintained at 0.5% or less in the 400 to 750 nm band. In the lens 1, the spectral reflectance gradually increases as the wavelength increases in the bandwidth band, the peak value appears, and the spectral reflectance gradually decreases from the peak value as the wavelength further increases. There are two peak value holding bands 4. Of the peak value holding bands 4, the peak value holding band 4 that exists in the short wavelength band is described as a peak band 4A, and the peak value holding band 4 that exists in the long wavelength band is described as a peak band 4B.

  The peak band 4A has a wavelength ranging from 410 nm to 530 nm. The peak band 4B occupies a wavelength range of 530 nm to 725 nm. The number of peak value holding bands 4 of the lens 1 is two, and the peak band 4A having the minimum bandwidth of the peak value holding band 4 is “(350 nm / 2) /1.6=109.375 nm”. It has a bandwidth of 120 nm that is greater than or equal to the value. If the bandwidth is equal to or greater than the value obtained by the above formula, the peak value holding band 4 has a gentle base with respect to the peak value. In the case of the peak value holding band 4 having such a gentle skirt, the peak value of the peak value holding band 4 can be easily controlled within a desired range in manufacturing.

  The wavelength of the peak value of the peak band 4A is 455 nm. The wavelength of the peak value in the peak band 4B is 625 nm. Therefore, the lens 1 has two peak value holding bands 4, and the peak values of the peak bands 4A and 4B are wavelengths other than the wavelengths of 490 to 575 nm, which are green. For this reason, when used as a projector lens, the transmittance of at least green among the three primary colors of red, blue and green is increased, which is preferable for a projector.

(Lens 1 manufacturing method)
The lens 1 is manufactured by arranging the alumina layer 3A, the mixed layer 3B1, the magnesium layer 3C1, the mixed layer 3B2, the magnesium layer 3C2, the mixed layer 3B3, and the magnesium layer 3C3 in this order on the surface of the lens body 2 by a vacuum deposition method. The At that time, the deposition rate and / or deposition time is adjusted to adjust the film thickness of each layer.

(Main effects obtained by the first embodiment of the present invention)
In the lens 1, the number of layers of the antireflection film 3 is seven. By increasing the number of layers to 7 or more, it becomes easy to obtain an antireflection effect in a long wavelength band exceeding 600 nm. Therefore, the lens 1 can obtain an antireflection effect in the band up to 750 nm in addition to the normal visible light band of 400 to 700 nm. In addition, the lens 1 can have a bandwidth band in which the spectral reflectance is maintained at 0.5% or less in the band from 400 to 750 nm. Specifically, as shown in FIG. 3, the spectral reflectance is 0.5% or less in the range of 400 to 790 nm.

  For reference, FIG. 4 shows the change in spectral reflectance with respect to wavelength of a lens in which the number of layers of the antireflection film 3 is 5, as in FIG. FIG. 5 shows the thickness of each layer constituting the antireflection film of this lens. As shown in FIG. 5, this lens has no layers corresponding to the mixed layer 3B3 and the magnesium layer 3C3, and the thicknesses of the layers corresponding to the alumina layer 3A, the mixed layer 3B1, the magnesium layer 3C1, the mixed layer 3B2, and the magnesium layer 3C2. Is different from that in the lens 1. As a result, this lens has an antireflection effect optimized when the number of layers of the antireflection film is 5 using an alumina layer, a mixed layer, and a magnesium layer.

  The thickness of each layer of the antireflection film optimized for the antireflection effect when the number of layers of the antireflection film is five is the highest for both the layer corresponding to the magnesium layer 3C2 and the layer corresponding to the alumina layer 3A. thick. Then, the layer corresponding to the mixed layer 3B2 is thick, and then the thickness is decreased in the order of the layer corresponding to the mixed layer 3B1 and the layer corresponding to the magnesium layer 3C1.

  As shown in FIG. 4, in this lens, the antireflection effect in a long wavelength band exceeding 700 nm is inferior to that in the lens 1 shown in FIG. Although such a lens has an advantage in a projector having a narrow light region to be handled, the lens has a sufficient antireflection effect for a camera lens or the like that handles the entire visible light region. This demonstrates the superiority of the antireflection effect of the lens 1 in which the number of layers of the antireflection film 3 is seven. This lens has only one peak value holding band that occupies a large region from 440 nm to approximately 600 nm.

  Further, by making the number of layers of the antireflection film 3 9 or less or 11 or less, the burden of manufacturing due to the increase in the number of arrangement of each layer is reduced, and the thickness of each layer can be increased to a certain level or more, thereby controlling the thickness. Can be easily.

  Further, since the antireflection film 3 has a bandwidth band in which the spectral reflectance is maintained at 0.5% or less in the band from 400 to 785 nm, the lens 1 has good antireflection characteristics. The lens 1 has two peak value holding bands 4 in a bandwidth band having a spectral reflectance of 0.5% or less and a bandwidth band having a spectral reflectance of 2% or less. When there are two peak value holding bands 4, it is easy to easily set and manufacture the arrangement conditions of the antireflection film 3 capable of making the spectral reflectance substantially uniform in the 400 to 750 nm band. Therefore, according to the embodiment of the present invention, in manufacturing the lens 1, a lens manufacturing method that makes it easy to make the spectral reflectance uniform is provided, and the lens 1 having a configuration that makes it easy to manufacture the lens 1 having the uniform spectral reflectance. Can be provided.

  As described above, the reason why the arrangement conditions of the antireflection film 3 capable of making the spectral reflectance substantially uniform in the band from 400 to 785 nm can be easily set will be described. When there are two peak value holding bands 4, if the peak value of one peak value holding band 4 is set small, the peak value of the other peak value holding band 4 becomes large, When the peak value is set large, the peak value of the other peak value holding band 4 tends to be small. This tendency is the same when there are three or more peak value holding bands 4. That is, among the three or four peak value holding bands 4, if the peak value of one peak value holding band 4 is set small, the peak value of the other peak value holding band 4 becomes large, and one peak value holding When the peak value of the band 4 is set large, the peak values of the other peak value holding bands 4 tend to be small.

  From this, when setting the peak values of all the peak value holding bands 4 uniformly, since the number of the peak value holding bands 4 to be noticed is small in the lens 1, the arrangement condition of the antireflection film 3 is set. It is easy to set. As the number of layers of the antireflection film 3 is increased to 8 layers, 9 layers, and 10 layers, the number of peak value holding bands 4 tends to increase. In consideration of this point, in the case of 7 layers, 8 layers, or 9 layers, it is preferable to have 2 or 3 peak value holding bands 4, and 7 layers, 8 layers, 9 layers, 10 layers, or 11 layers. In this case, it is preferable that the peak value holding band 4 is two, three, or four.

  Note that the number of peak value holding bands 4 to be noted is most preferably two, three is next preferable, and four is next preferable. Here, since the number of peak value holding bands 4 to be noted is difficult to be one when the number of layers of the antireflection film 3 is increased from 7 to 9 or from 7 to 11, Two, three, or four are preferred as the appropriate number.

  Further, the lens 1 has a peak 4A bandwidth which is the minimum bandwidth of the peak value holding band 4, and the number of the peak value holding bands 4 is x (350 nm / x) /1.6. It is more than the value. As a result, the bandwidth occupied by the peak value holding band 4 existing in the range of 350 nm, which is the light range of 400 to 750 nm, can be made a certain level or more. Then, the change rate of the peak value when the peak values of all the peak value holding bands 4 are set within a predetermined value can be reduced, and the setting can be performed stably.

  The lens 1 has two peak value holding bands 4 and the peak value is set to a wavelength other than the wavelength of 490 to 575 nm which becomes green. Therefore, antireflection can be performed particularly well for one of the three primary colors.

  In the manufacturing method of the lens 1, each layer such as the alumina layer 3 </ b> A is disposed by a vacuum deposition method, and the deposition rate and / or deposition time is adjusted at the time of the placement to adjust the film thickness of each layer. Therefore, it is possible to provide a method for manufacturing a lens that can easily make the spectral reflectance uniform.

(About the lens according to the second embodiment)
Next, the lens 10 according to the second embodiment will be described with reference to FIGS. In FIG. 6, as the lens 10 according to the second embodiment, optical thicknesses of layers corresponding to the respective layers of the lens 10 using silica (SiO ₂ ) layers instead of the magnesium layers 3C1 and 3C2 in the lens 1 are illustrated. Is shown. In FIG. 6, the reference numeral of the silica layer 3D1 is used as the silica layer corresponding to the magnesium layer 3C1 in the lens 1, and the reference numeral of the silica layer 3D2 is used as the silica layer corresponding to the magnesium layer 3C2 in the lens 1. Hereinafter, the silica layers 3D1 and 3D2 are collectively referred to as a silica layer 3D. The lens 10 has the same configuration as that of the lens 1 except for the configuration of each of these layers. The total physical film thickness of these seven layers is 320 nm. The manufacturing method of the lens 10 is the same as the manufacturing method of the lens 1. The refractive index of the silica layer 3D is 1.46.

  This lens 10 has the spectral reflectance characteristic shown in FIG. The peak value holding band of the short wavelength band occupies 410 nm to 540 nm. The peak value holding band of the long wavelength band occupies from 540 nm to 750 nm. This lens 10 can particularly preferably obtain an antireflection effect in a long wavelength band. Therefore, this lens 10 can obtain an antireflection effect over a wider band than the lens 1. In addition, the lens 10 has a bandwidth band in which the spectral reflectance is approximately 0.5% or less in the 400 to 750 nm band.

  The lens 10 has a spectral reflectance of 1% or less in the band of 380 to 850 nm, and further has a spectral reflectance of 2% or less in the band of 375 to 900 nm.

  From the film thickness shown in FIG. 6, the layer corresponding to the mixed layer 3B2 among the layers is the thickest as the optical film thickness. The next thicker layer corresponds to the magnesium layer 3C3. The other layers are approximately half the thickness of the layer corresponding to the magnesium layer 3C3, the layer corresponding to the mixed layer 3B1, the layer corresponding to the alumina layer 3A, the layer corresponding to the mixed layer 3B3, and the silica layer 3D1. The thickness decreases in the order of the corresponding layer and the layer corresponding to the silica layer 3D2. The lens 10 has the same effect as the lens 1.

(Regarding the lens according to the third embodiment)
Next, a lens 20 according to a third embodiment will be described with reference to FIGS. In FIG. 8, as the lens 20 according to the third embodiment, a mixed layer 3B4 is formed on the surface of the magnesium layer 3C3 which is the outermost layer of the lens 1, and a magnesium layer 3C4 is formed on the surface of the mixed layer 3B4. A longitudinal sectional view of the lens 20 in which the thickness of the lens 20 is optimized from the viewpoint of preventing reflection is shown in the same manner as FIG. Note that the reference numerals assigned to the constituent elements other than the mixed layer 3B4 and the magnesium layer 3C4 in FIG. 8 are the same reference numerals as those in the lens 1 as corresponding to the constituent elements in the lens 1. The mixed layer 3B4 is the same component as the mixed layers 3B1, 3B2, and 3B3, and the magnesium layer 3C4 is the same component as the magnesium layers 3C1, 3C2, and 3C3. This lens 20 has nine layers, which is two more antireflection films than the lens 1. The total physical film thickness of these nine layers is 570 nm. The manufacturing method of the lens 20 is the same as the manufacturing method of the lens 1.

  FIG. 9 shows the change in the spectral reflectance with respect to the wavelength of the lens 20 as in FIG. This lens 20 has three peak value holding bands 4 in a band of 400 to 750 nm. The peak value holding band 4 of the shortest wavelength band occupies 400 nm to 465 nm. Next, the peak value holding band 4 of the short wavelength band occupies from 465 nm to 590 nm. The peak value holding band 4 of the longest wavelength band occupies from 590 nm to 775 nm.

  In the three peak value holding bands 4 shown in FIG. 9, the peak values of the spectral reflectances are close to 1%, and the bandwidth band in which the spectral reflectances are kept at 1% or less can be more easily spread than that of the lens 1. The lens 20 has the same effect as the lens 1.

(Other forms)
The manufacturing method of the lens 1 and the lenses 1, 10, 20 in the embodiment of the present invention have been described above, but various modifications can be made without departing from the gist of the present invention. In the following description, the same reference numerals are assigned to the components corresponding to the lens 1 when the modified examples of the lenses 1, 10 and 20 are described.

  In the embodiment of the present invention, the lenses 1, 10, and 20 are employed as optical members, but various other lenses, mirrors, optical filters, prisms, antireflection members disposed on the light receiving surface of the solar cell, and the like. The optical member can be employed.

  The number of layers of the antireflection film 3 of the lenses 1 and 10 is 7, but may be 8, 9, 10 or 11. The number of layers of the antireflection film 3 of the lens 20 is 9, but may be 7, 8, 10 or 11. From the viewpoint of reducing the burden of the arrangement of each layer and facilitating the control of the thickness of each layer, the number of layers of the antireflection film 3 of the lenses 1, 10, 20 is set to a small value of 7, 8, or 9. Is preferred.

  As described above, the antireflection film 3 of the lens 1 is arranged on the lens body 2 in the order of the alumina layer 3A, the mixed layer 3B1, the magnesium layer 3C1, the mixed layer 3B2, the magnesium layer 3C2, the mixed layer 3B3, and the magnesium layer 3C3. Has been. The lenses 10 and 20 are also arranged as described above. The order of arrangement of these layers, the material of the layers to be arranged, the composition, etc. can be changed. For example, the same kind of substances may be arranged adjacent to each other. Further, for example, the alumina layer 3A may not be disposed directly on the lens body 2, or between the mixed layer 3B and the magnesium layer 3C, between the mixed layer 3B and the silica layer 3D, or between the silica layer 3D and magnesium. It may be arranged between the layer 3C and the like.

The antireflection film 3 uses the alumina layer 3A, but instead of the alumina layer 3A, PrAlO ₃ , La ₂ O ₃ .8.8Al ₂ O ₃ , Y ₂ O ₃ , or ZrO ₂ A mixture of Al ₂ O ₃ and the like can be used.

Moreover, although the mixed layer 3B is used for a part of the antireflection film 3, TiO ₂ , ZrO ₂ , Ta ₂ O ₅ , LaTiO ₃ , HfO ₂ , Nb ₂ O _5, or the like can be used. Furthermore, although the magnesium layer 3C is used for a part of the antireflection film 3, SiO ₂ or the like can be used instead of the whole or a part of the magnesium layer 3C as in the lens 10. Furthermore, the thickness of each layer of the antireflection film 3 can be changed.

  The lens 1 has two peak value holding bands 4 in a band from 400 to 750 nm. However, the number of the peak value holding bands 4 can be three or four. Further, although the peak band 4A and the peak band 4B are adjacent to each other, there is a portion where the same spectral reflectance value continues between the two, so that a plurality of peak value holding bands 4 may appear apart from the wavelength axis. good.

  The lenses 1 and 10 have a bandwidth band in which the spectral reflectance is maintained at 0.5% or less in the band from 400 to 750 nm. However, it is not necessary to maintain such a low spectral reflectance. If the spectral reflectance is maintained at 2% or less in the band from 400 to 750 nm, the lens has a sufficient antireflection effect. This spectral reflectance is preferably small. Therefore, 1.5% is preferable to 2%, 1% is preferable to 1.5%, 0.5% is preferable to 1%, and 0.4%, 0.3%, or 0. Needless to say, 2% or less is more preferable.

  The lenses 1 and 10 have two peak value holding bands 4 and have a peak value other than a wavelength of 490 to 575 nm which becomes green. However, it is not always necessary to satisfy such a condition. For example, the peak value may be a wavelength other than the wavelength of 610 to 750 nm that is red. By doing so, antireflection can be performed particularly well for red. Further, for example, the peak value may be a wavelength other than the wavelength of 435 to 480 nm that is blue. By doing so, antireflection can be performed particularly well for blue.

  When the lens is the same as the lens 20 and has a film thickness of 570 nm and a magnesium layer other than the ninth magnesium layer (magnesium layer 3C4 in the lens 20) is a silica layer (a modified lens of the lens 20), the spectral reflectance is A band of 1% or less is widened. However, when the thickness of each layer of the deformed lens of the lens 20 is adjusted so that the bandwidth with a low spectral reflectance is wider than that of the lens 20, the peak value, particularly the spectral reflection of the peak value on the shortest wavelength side, is adjusted. The rate is about 1.3%. Further, in the deformed lens of the lens 20, when the thickness of each layer is adjusted so as to widen the bandwidth band having low spectral reflectance from 400 to 900 nm, the spectral reflectance of the peak value becomes about 1.8%.

  In the lens having the same configuration as the lens 20, a lens in which a new mixed layer 3B is arranged on the surface of the outermost magnesium layer 3C4 and a new magnesium layer 3C is arranged on the surface of the mixed layer 3B will be described. . This lens has 11 more antireflection films than the lens 20. Since this lens has many layers, it is preferable to reduce the thickness of each layer. The reason for this is that if the antireflection effect is optimized with this number of layers, the total thickness of the antireflection film becomes twice or more that of the antireflection film 3 of the lens 1 and the manufacturing cost increases. When the total physical film thickness of the antireflection film 3 is 700 nm, the physical film thickness of the minimum thickness layer is 14 nm, the spectral reflectance band of 1% or less is 400 to 850 nm, and the peak value is 0.6. There is an example of less than%.

  Therefore, if the thickness of each layer of the lens is changed to make the antireflection effect appropriate, a thin layer having a physical film thickness of 5 or 6 nm is included in a part of each layer. Then, it is difficult to obtain the uniformity of the thickness of the thin layer. In such an example, the total physical film thickness of the antireflection film 3 is 360 nm, the spectral reflectance band of 1% or less is 400 to 850 nm, and the peak value is 0.7% or less. Therefore, if the physical thickness of the thinnest film is set to 18 nm or more so as to obtain the uniformity of the thickness of the thin layer and the antireflection effect is appropriate, the peak value of the spectral reflectance is close to 2%. become.

  For lenses with 9 or 11 antireflective coatings, it is necessary to provide a lens manufacturing method that facilitates uniform spectral reflectance and to manufacture lenses with uniform spectral reflectance. This has the effect of providing a lens having a configuration that is easy to manufacture.

  When the bandwidth of the peak value holding band 4 which is the minimum value of the bandwidth of the peak value holding band 4 is x, the number of the peak value holding bands 4 is “(350 nm / x) / The value is 1.6 or more. Although it is preferable to set this value or more, it is not always necessary to satisfy such a condition. For example, the condition such that the bandwidth of the peak value holding band 4 is equal to or greater than the value of “(350 nm / x) /1.4” may be satisfied. Instead of the numerical value of “1.4”, a numerical value such as “1.2”, “1.3”, “1.5”, “1.7”, or “1.8” may be used. it can.

  Glass is used for the lens body 2, but instead of glass, a light-transmitting resin such as acrylic resin, polycarbonate, polystyrene, or polyester may be used. The lens body 2 has a refractive index of 1.52, but has a refractive index of 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1. 1.9, 1.95, 2.0 can be used. Thus, even if the refractive index of the lens body is changed, a lens having the same antireflection effect as that of the lens 1 can be obtained by selecting the material of each layer of the antireflection film 3 and adjusting the thickness. it can.

  In the manufacturing method of the lenses 1, 10, and 20, adjustment of the arrangement condition of each layer of the antireflection film 3 is adjustment of the thickness of the film, but it is not always necessary to do so. For example, the arrangement condition of each layer may be adjusted by changing the material of the film to be arranged, increasing or decreasing the number of layers of the film to be arranged, and the like.

  Moreover, in the manufacturing method of the lenses 1, 10, and 20, the layers of the antireflection film 3 are arranged by vacuum deposition, but it is not always necessary to do so. For example, each layer may be disposed by sputtering, chemical vapor deposition, or the like.

It is a longitudinal cross-sectional view which shows schematic structure of the lens which concerns on the 1st Embodiment of this invention. It is a figure which shows the optical film thickness and physical film thickness of each layer which comprise the antireflection film of the lens shown in FIG. 1, and the refractive index of a lens main body. It is a figure which shows the change of the spectral reflectance with respect to the wavelength of the lens shown in FIG. It is a figure for comparison with the lens which concerns on embodiment of this invention, and is a figure which shows the change of the spectral reflectance with respect to the wavelength of the lens which made the number of layers of the film | membrane of an antireflection film into five. It is a figure which shows the optical film thickness of each layer which comprises the antireflection film of the lens which has the spectral reflectance shown in FIG. It is a figure which shows the optical film thickness of each layer of the antireflection film of the lens concerning the 2nd Embodiment of this invention, and the refractive index of a lens main body. It is a figure which shows the change of the spectral reflectance with respect to the wavelength of the lens shown in FIG. It is a longitudinal cross-sectional view which shows schematic structure of the lens which concerns on the 3rd Embodiment of this invention. It is a figure which shows the change of the spectral reflectance with respect to the wavelength of the lens shown in FIG.

Explanation of symbols

1,10,20 Lens (optical member)
3 Antireflection film 4 Peak value holding band

Claims (7)

In the method of manufacturing an optical member in which a plurality of layers are arranged on the surface to form an antireflection film,
The number of layers of the film is 7 to 9,
The antireflection film has a bandwidth that maintains a spectral reflectance of 2% or less in the band from 400 to 750 nm, and the spectral reflectance gradually increases as the wavelength increases in the bandwidth. And the arrangement condition of the film is adjusted so as to have two or three spectral reflectance peak value holding bands in which the spectral reflectance gradually decreases from the peak value as the wavelength increases. A method for manufacturing an optical member. In the method of manufacturing an optical member in which a plurality of layers are arranged on the surface to form an antireflection film,
The number of layers of the film is 7 to 11,
The antireflection film has a bandwidth that maintains a spectral reflectance of 2% or less in the band from 400 to 750 nm, and the spectral reflectance gradually increases as the wavelength increases in the bandwidth. As the wavelength increases, the spectral reflectance gradually decreases from the peak value as the wavelength increases, so that there are two to four spectral reflectance peak holding bands, and the bandwidth of the peak holding band A method for producing an optical member, characterized in that the arrangement condition of the film is adjusted so that the minimum value is not less than a value of “(350 nm / x) /1.6” where x is the number of peak value holding bands .   3. The method of manufacturing an optical member according to claim 1, wherein the adjustment of the arrangement condition is adjustment of the thickness of the film.   4. The method of manufacturing an optical member according to claim 1, wherein one of the peak values exists between wavelengths of 600 to 650 nm. In an optical member comprising an antireflection film comprising a plurality of layers on the surface,
The number of layers of the antireflection film is 7 to 9,
The antireflection film has a bandwidth that maintains a spectral reflectance of 2% or less in the band from 400 to 750 nm, and the spectral reflectance gradually increases as the wavelength increases in the bandwidth. An optical member having two or three spectral reflectance peak value holding bands in which the spectral reflectance gradually decreases from the peak value as the wavelength increases and the wavelength increases. In an optical member comprising an antireflection film comprising a plurality of layers on the surface,
The number of layers of the antireflection film is 7 to 11,
The antireflection film has a bandwidth that maintains a spectral reflectance of 2% or less in the band from 400 to 750 nm, and the spectral reflectance gradually increases as the wavelength increases in the bandwidth. Appears and the spectral reflectance gradually decreases from its peak value as the wavelength increases, and the spectral reflectance has two to four peak value holding bands, and the minimum bandwidth of the peak value holding band An optical member characterized in that the value is equal to or greater than “(350 nm / x) /1.6” where x is the number of peak value holding bands.   The optical member according to claim 5, wherein the peak value holding band is two, and the peak value is a wavelength other than a wavelength of 490 to 575 nm which becomes green.

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