JP5493623B2 - Optical parts - Google Patents

Description

  The present invention relates to an optical system component, and more particularly to an optical system component for housing an optical element therein.

  2. Description of the Related Art Conventionally, a lens barrel unit provided in a camera or the like has an optical element such as a lens, a lens barrel that houses the optical element therein, a diaphragm member that adjusts the amount of light, and a desired optical element by moving the optical element. It has a configuration having a moving member for securing the focal length and a fixing member for fixing the lens barrel unit to a main body such as a camera.

  Among them, like the lens barrel, it is necessary to take an antireflection measure or a light shielding measure on the inner wall surface of a member that accommodates an optical element inside and forms an optical path or is disposed in the optical path. This is because off-axis light that does not contribute to the formation of the subject image out of light incident on the lens barrel is reflected by the inner wall surface of the lens barrel, and the reflected light becomes stray light inside the lens barrel. This is because there is a problem that the image quality is deteriorated by reaching the image pickup device and generating so-called flare or ghost.

  Conventionally, as a method of adding an antireflection or light shielding function to the inner wall surface of the lens barrel, a slope (V groove) is formed on the inner wall surface of the lens barrel in consideration of a step or a light reflection angle. And machining methods such as performing satin processing. However, since the incident light to the inside of the lens barrel is reflected in a complicated direction by the parts inside the lens barrel, it is difficult to sufficiently reduce the reflection by such a machining method. there were.

  On the other hand, as another method of adding an antireflection or light shielding function to the inner wall surface of the lens barrel, a black paint or matte paint is applied to the inner wall surface of the lens barrel to form a light absorbing and scattering member. The chemical film formation method which reduces a degree is mentioned (for example, refer patent documents 1-3).

JP 2003-277722 A JP-A-11-64703 JP-A-5-341167

  However, even if black paint or matte paint is applied to the inner wall surface of the lens barrel using the means as described in Patent Documents 1 to 3, it does not contribute to the formation of the subject image incident on the inside of the lens barrel. Since the off-axis light cannot be absorbed sufficiently, the glossiness of the inner wall surface (glossiness at an incident angle of 60 °) cannot be lowered to a sufficient level (0.5 or less). In some cases, light reflected at the interface between the painted surface and air reaches the image sensor as stray light inside the lens barrel. As a result, the so-called flare, ghost, and the like are generated, and the problem of reducing the image quality still remains.

  The above-mentioned Patent Document 1 relates to a matting agent used for the purpose of lowering glossiness and a coating composition using the same, and is characterized by blending cellulose powder, which is a natural polymer, into a coating material. . However, the effect is the same glossiness as that of powdered silica that has been used in the past, and a glossiness of 1.5 (Example 3), which is necessary for exteriors mainly for taste, and is an optical system component such as a lens barrel. Since the required glossiness is 0.5 or less, the image quality cannot be improved by suppressing the occurrence of so-called flare and ghost.

  Patent Document 2 described above is an electrodeposition coating film formed using an electrodeposition paint in which fine particles are dispersed. However, especially for fine particles, the shape may be of one type or a plurality of types, and secondly, there is no mention of coloration, so-called flare or ghost. It has not been possible to improve the image quality by suppressing the occurrence of the above.

  Patent Document 3 described above relates to antireflection inside the lens barrel of the projection television receiver, and by forming a fluorine-based compound thin film lower than the refractive index of the barrel material on the inner surface of the barrel. It aims at antireflection effect. However, with this method, although the reflectance is reduced by several percent, it cannot be reduced to a glossiness of 0.5 or less required for an optical system component such as a lens barrel. Here, the glossiness is defined such that the reflectance with respect to the glass mirror polished surface having a refractive index of 1.567 is glossiness 100, and the actual reflectance of this glass mirror surface is 10% when the incident angle is 60 °. Therefore, the glossiness 0.5 is 0.05%, which is almost non-reflective. Accordingly, it is almost impossible to reduce the glossiness to 0.5 or less simply by preventing reflection. In order to reduce the glossiness to 0.5 or less, surface irregularities for surface diffusion are required. From the above, Patent Document 3 cannot improve the image quality by suppressing the occurrence of so-called flare and ghost.

  The present invention has been made in view of such circumstances, and can reduce the reflectance of off-axis light incident on the inside, thereby suppressing the occurrence of so-called flare and ghost and improving the image quality. An object of the present invention is to provide an optical system component that can be made to operate.

In order to solve such a problem, the present invention provides a plurality of optical system components (1) for accommodating optical elements (2, 3) in the inner wall surface (10) of the optical system components (1). A black coating film (15) made of a film-forming resin (16) containing the fine particles (17) is coated, and the plurality of fine particles (17) are made of a plurality of types of shapes, and a part or All project from the surface of the film-forming resin (16), whereby the surface of the black coating film (15) has an uneven shape, and the refractive index of the fine particles (17). Is characterized in that it is an optical system component (1) matched to the refractive index of the film-forming resin (16) .

  Here, in order to explain the present invention in an easy-to-understand manner, the description has been made in association with the reference numerals of the drawings representing the embodiments. However, it is needless to mention that the present invention is not limited to the embodiments. .

According to the present invention, on the inner wall surface of the optical system component, a black coating made of a film-forming resin comprising a plurality of types and a part or all of which protrudes from the surface of the film-forming resin. In addition to the film being coated , the refractive index of the fine particles is matched to the refractive index of the film-forming resin, so the blackness can be increased while reducing the glossiness of the inner wall surface of the optical system component. The reflectance of off-axis light incident on the inside of the optical system component can be lowered. As a result, it is possible to suppress the occurrence of so-called flare and ghost, improve the image contrast, and improve the image quality.

It is sectional drawing which shows the lens barrel which concerns on embodiment of this invention. It is a schematic sectional drawing which shows the mode of the inner wall face in the lens barrel of FIG.

  Embodiments of the present invention will be described below.

  In the present embodiment, a lens barrel provided in a camera or the like will be described as an example of the optical system component of the present invention.

  FIG. 1 is a cross-sectional view showing a lens barrel according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing the state of the inner wall surface of the lens barrel of FIG.

  First, an outline of a lens barrel 1 as an embodiment of the optical system component of the present invention will be described with reference to FIG. The lens barrel 1 according to the present embodiment constitutes one part of a lens barrel unit provided in a camera or the like, and the lens barrel unit includes a front group lens group 2 and a rear group as optical elements. The lens group 3, the lens barrel 1 that accommodates the front group lens group 2 and the rear group lens group 3, the diaphragm member (not shown) for adjusting the amount of light, the front group lens group 2 and the rear group lens group 3 are moved. In this configuration, a movable member (not shown) for securing a desired focal length and a fixing member (not shown) for fixing the lens barrel unit to a main body such as a camera are provided.

  The lens barrel 1 of the present embodiment has a configuration in which a base 11 made of a metal such as aluminum or plastic is formed in a substantially cylindrical shape. Further, the front lens group 2 is housed inside the lens barrel 1 on the subject side in the substantially cylindrical generatrix direction, and in the lens barrel 1 on the camera side in the substantially cylindrical generatrix direction. The rear lens group 3 is accommodated. In the present embodiment, the base 11 of the lens barrel 1 is made of aluminum.

  Next, the configuration of the inner wall surface 10 of the lens barrel 1 will be described with reference to FIG.

  A black coating film 15 is coated on the base material 11 on substantially the entire surface of the substantially cylindrical inner wall surface 10 of the lens barrel 1 including between the front lens group 2 and the rear lens group 3 described above. Yes. As shown in FIG. 2, the black coating film 15 is configured to include a plurality of fine particles 17 in a film forming resin 16. Among these, the film-forming resin 16 is a resin solid content of a black colored paint made of acrylic urethane or the like, and a predetermined amount of a plurality of fine particles 17 are added to form a black coating film 15.

  Further, as shown in FIG. 2, the plurality of fine particles 17 have a plurality of types of shapes including a sphere, a cone, a column, a shape obtained by combining, breaking, and deforming these. . In this way, by making the plurality of fine particles 17 have a plurality of types of shapes, the light absorption / scattering effect is enhanced and the glossiness can be lowered.

  Further, as shown in FIG. 2, a part or all of the plurality of fine particles 17 protrude a predetermined amount from the surface of the added film-forming resin 16, whereby the surface of the black coating film 15 is flat. Instead, the shape is uneven. As described above, since the plurality of fine particles 17 protrude from the surface of the film forming resin 16, the light absorption / scattering effect is enhanced and the glossiness can be lowered.

  The plurality of fine particles 17 of the present embodiment are made of polymethyl methacrylate-based polymethacrylic acid resin (PMMA, acrylic resin, methacrylic resin) having a refractive index of 1.49, and polyacrylonitrile having a refractive index of 1.52. It consists of polymer materials such as polyacrylonitrile and polyacrylate. In the examples described later, fine particles made of polymethyl methacrylate resin are used as the plurality of fine particles 17 because the refractive index is low (1.49). However, polyacrylonitrile (refractive index 1) is used. .52) and the like can obtain substantially the same effect. Further, the polyacrylonitrile is superior to the polymethyl methacrylate resin in terms of adhesion to the film-forming resin 16.

  Thus, by making the plurality of fine particles 17 of a resin (polymer material) whose refractive index can be adjusted, the refractive index of the fine particles 17 can be matched to the refractive index of the film-forming resin 16 to be added. It becomes possible. By matching the refractive indexes of the fine particles 17 and the film forming resin 16, the light incident on the fine particles 17 can be transmitted without being scattered at the interface between the fine particles 17 and the film forming resin 16. By reducing this scattered light, the blackness of the black coating film 15 becomes stronger and also the glossiness is lowered. In the past, silica particles used as true spherical particles have a refractive index fixed at about 1.55, and if it is desired to reduce scattering at the interface, the film-forming resin must be adjusted. Therefore, it was very difficult.

  Further, as shown in FIG. 2, a fluorine compound coating is further formed on the black coating film 15 (inside the lens barrel) made of the film forming resin 16 including a plurality of fine particles 17 having a plurality of types of shapes. The layer 18 (a layer made of a fluorine compound) is preferably formed. Here, the fluorine compound coating layer 18 is preferably thin. At least, the fluorine compound coating layer 18 has a flat uneven shape of the plurality of fine particles 17 protruding from the surface of the film forming resin 16. It is necessary to have a thickness that does not make it difficult. The fluorine compound coating layer 18 may be a colorless and transparent coating layer. By forming the fluorine-based compound coating layer 18, the blackness of the black coating film 15 can be further increased and the glossiness can be lowered.

  Next, specific examples of the above-described embodiment will be described with reference to Table 1. Here, fine particles 17 made of polymethyl methacrylate resin (PMMA) are added at a predetermined ratio to the resin 16 for film formation, which is a fixed resin part of a black colored paint made of acrylic urethane, and a stirrer Tori Netaro AR-500: manufactured by Shinky Co., Ltd. A film 15 was formed. And the glossiness in the incident angle of 60 degrees was measured about the black coating film 15 formed in this way.

  Table 1 describes various conditions in Examples 1-2 and Comparative Examples 1-2 of the black coating film 15 formed by imposing various conditions on the above-described forming method, and the measurement results of the respective glossiness, etc. did.

  Example 1 is made of polymethyl methacrylate resin (PMMA) with respect to a film-forming resin that is a resin-fixed portion of a black colored paint made of acrylic urethane, and is indefinite (consisting of a plurality of types). Fine particles with a fine particle diameter (longest part length) of 3 μm are added at a rate of 40 wt% with respect to the film-forming resin, and sufficient with a stirrer (Awatori Kentaro AR-500: manufactured by Shinky Corporation) After stirring, spray coating is performed on the base material (substrate) made of unpainted aluminum and dried in an oven to form a black paint film with a thickness of about 10 μm. The substrate was dip coated with a fluorine-based surface treatment coating solution (Novec EGC-1720: manufactured by Sumitomo 3M), dried at 60 ° C. for 30 minutes, and left for 1 day. A fluorine compound coating layer is formed on the coating film. As a result of measuring the glossiness at an incident angle of 60 ° with respect to Example 1, it was 0.3. Moreover, as a result of measuring the brightness index with respect to this Example 1, it was 17.0.

  Example 2 is made of a polymethyl methacrylate resin (PMMA) with respect to a film-forming resin that is a resin-fixed portion of a black colored paint made of acrylic urethane, and is indefinite (consisting of a plurality of types). Fine particles with a fine particle diameter (longest part length) of 3 μm are added at a rate of 40 wt% with respect to the film-forming resin, and sufficient with a stirrer (Awatori Kentaro AR-500: manufactured by Shinky Corporation) Then, the mixture is spray-coated on a base (substrate) made of uncoated aluminum and dried in an oven to form a black coating film having a thickness of about 10 μm. No fluorine compound coating layer is formed. With respect to Example 2, the glossiness at an incident angle of 60 ° was measured and found to be 0.3. Moreover, as a result of measuring the brightness index with respect to this Example 2, it was 19.6.

  Comparative Example 1 is a film-forming resin that is a resin-fixed portion of a black colored paint made of acrylic urethane, and is made of polymethyl methacrylate resin (PMMA), has a spherical shape, and a fine particle diameter of 3 μm. A base material made of uncoated aluminum after being added at a rate of 20 wt% with respect to the film-forming resin and sufficiently stirred with a stirrer (Awatori Netaro AR-500: manufactured by Shinky Co., Ltd.) Spray coating on a substrate) and drying in an oven to form a black paint film having a thickness of about 10 μm. No fluorine compound coating layer is formed. As a result of measuring the glossiness at an incident angle of 60 ° with respect to the comparative example 1, it was 7.

  Comparative Example 2 is made of a polymethyl methacrylate resin (PMMA) with respect to a film-forming resin that is a resin-fixed portion of a black colored paint made of acrylic urethane, and is indefinite (consisting of a plurality of types). Fine particles with a fine particle diameter (longest part length) of 3 μm are added at a rate of 20 wt% with respect to the film-forming resin, and sufficient with a stirrer (Awatori Kentaro AR-500: manufactured by Shinky Corporation) Then, the mixture is spray-coated on a base (substrate) made of uncoated aluminum and dried in an oven to form a black coating film having a thickness of about 10 μm. No fluorine compound coating layer is formed. As a result of measuring the glossiness at an incident angle of 60 ° with respect to the comparative example 2, it was 3.

  Here, in order to achieve the object of the present invention, the glossiness at the incident angle of 60 ° of the inner wall surface of the optical system component needs to be 0.5 or less. It became 5 or less. On the other hand, in Comparative Examples 1-2, the glossiness was higher than 0.5.

  Further, when the conditions of Comparative Example 1 and Comparative Example 2 are compared, the shape of the fine particles is a true spherical shape in Comparative Example 1, whereas it is indefinite (consisting of a plurality of types of shapes) in Comparative Example 2. Other conditions are the same. When the measurement results of Comparative Example 1 and Comparative Example 2 are compared, the glossiness is 7 in Comparative Example 1 and 3 in Comparative Example 2. From this, it was found that when the shape of the fine particles is indefinite (consisting of a plurality of types of shapes), the glossiness is lower than in the case of a true spherical shape. That is, it was found that the image quality can be improved when the shape of the fine particles is indefinite (consisting of a plurality of types of shapes).

  Further, when the conditions of Example 1 and Example 2 are compared, Example 1 has a fluorine compound coating layer, whereas Example 2 does not have a fluorine compound coating layer. The conditions are the same. When the measurement results of Example 1 and Example 2 are compared, the glossiness is 0.3, but the lightness index is 17.0 in Example 1, whereas 19. 6 From this, it was found that the brightness index decreases when the fluorine compound coating layer is provided. That is, it has been found that the image quality can be improved by having a fluorine compound coating layer.

  From the above, in the black paint film, the shape of the fine particles is indefinite (consisting of multiple types of shapes), and having a fluorine compound coating layer, the glossiness and brightness index are further reduced, It was found that the image quality can be further improved. In addition, about the result of the above-mentioned Example, the same result was obtained even when the film forming resin 16 was made of polyacrylonitrile.

As described above, according to the lens barrel 1 of the above-described embodiment, the inner wall surface of the lens barrel 1 in the lens barrel 1 for housing the front group lens group 2 and the rear group lens group 3 therein. 10 is coated with a black coating film 15 made of a film-forming resin 16 containing a plurality of fine particles 17, and the plurality of fine particles 17 have a plurality of types of shapes, part or all of which are for film formation. It protrudes from the surface of the resin 16, so that the surface of the black coating film 15 has an uneven shape, and the refractive index of the fine particles 17 is matched to the refractive index of the film forming resin 16. Therefore, the blackness can be increased while reducing the glossiness of the inner wall surface 10 of the lens barrel 1, and the reflectance of off-axis light that does not contribute to the formation of the subject image incident on the inside of the lens barrel 1 is reduced. be able to.

  As a result, so-called flare, ghost, etc. generated by the reflected light of off-axis light becoming stray light inside the lens barrel 1 and reaching the imaging device can be suppressed, image contrast can be improved, and image quality can be improved. Can be improved.

  Further, when the fine particles 17 are made of a polymer material or the fluorine-based compound coating layer 18 is formed on the black coating film 15, the blackness is further reduced while reducing the glossiness of the inner wall surface 10 of the lens barrel 1. The taste can be improved, and the reflectance of off-axis light that does not contribute to the formation of the subject image incident inside the lens barrel 1 can be reduced.

  As a result, it is possible to further suppress so-called flare, ghost, and the like that occur when reflected light of off-axis light becomes stray light inside the lens barrel 1 and reaches the image sensor, further improving the image contrast, The quality can be further improved.

  Each embodiment described above is described in order to facilitate understanding of the present invention, and is not described in order to limit the present invention.

  For example, in the above-described embodiment, the optical system component of the present invention is applied to a lens barrel for a camera. However, the present invention is not limited to this, and the optical system component of the present invention is not limited to this. In addition, the present invention can be applied to various types that accommodate optical elements such as video cameras and telescopes.

1 Lens barrel (optical parts)
2 Front lens group (optical element)
3 Rear lens group (optical element)
DESCRIPTION OF SYMBOLS 10 Inner wall surface 11 Base material 15 Black coating film 16 Film-forming resin 17 Fine particle 18 Fluorine compound coating layer (layer consisting of fluorine compound)

Claims (3)

In optical system parts for accommodating optical elements inside,
The inner wall surface of the optical system part is coated with a black paint film made of a film-forming resin containing a plurality of fine particles,
The plurality of fine particles have a plurality of types of shapes, and part or all of the fine particles protrude from the surface of the film-forming resin, whereby the surface of the black coating film has irregularities. It has become,
An optical system component , wherein a refractive index of the fine particles is adjusted to a refractive index of the film forming resin .   The optical system component according to claim 1, wherein the fine particles are made of a polymer material.   3. The optical system component according to claim 1, wherein a layer made of a fluorine compound is further formed on the black paint film.

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