JP2008307852A - Mold for manufacturing reticle, reticle, method of manufacturing them, and imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reticle having a micro lens array of a random configuration and a mold usable for manufacturing the same, and an imaging device using the same. <P>SOLUTION: The reticle having a transparent resin layer transferred with convexoconcaves of a mold for manufacturing the reticle is manufactured on the transparent substrate using the mold for manufacturing the reticle formed with an inorganic resist film having a plurality of the convexoconcaves of a micro lens configuration, and the reticle is used for the imaging device. Alternatively, the reticle formed with the inorganic resist film having a plurality of the micro lens on the transparent substrate is used for the imaging device. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a focusing screen used in an imaging apparatus such as a single-lens reflex camera and a mold used for manufacturing the focusing screen.

  The focusing screen is also referred to as a focusing plate, and is used when adjusting the focus of a single-lens reflex camera or the like.

  Conventionally, using a mold in which irregularities are formed by sanding a base material such as glass, the irregularities are transferred onto a plastic material such as acrylic resin, and a plastic member to which the irregularities are transferred is used as a focusing screen. Since such a focusing screen has a random shape with irregular surface irregularities, it has the advantage of good light diffusibility, natural blurring when adjusting focus, and easy focusing. ing. On the other hand, because the light diffusibility is good, the image from the focus plate is dark. There was a problem of worsening sex.

  On the other hand, in order to solve the above problems, a focusing screen in which a microlens (convex or concave microlens) array is formed on the surface of a plastic substrate or the like is also used. Such a focusing screen is manufactured as follows. First, a substrate coated with a photosensitizer such as a photoresist is prepared, patterned by an exposure process and a development process using a mask, and then a master disk is prepared by providing a fine microlens array with a regular arrangement. Then, a mold is produced from the master, and a focusing lens is produced by transferring the microlens shape from the mold to a plastic member. The focusing screen manufactured in this way has an advantage that the image projected on the focusing screen has no graininess and is bright. On the other hand, since the microlenses are regularly and periodically arranged, there is a drawback that the direction of diffracted light is limited to a specific direction and blurring becomes unnatural. Further, when used together with a Fresnel lens, there is also a drawback that moire fringes are generated due to interference with the annular structure of the Fresnel lens.

As described above, each of the two types of focusing plates has advantages and disadvantages. As a means for solving these disadvantages at the same time, a microlens having a random size and arrangement may be formed on the surface. As a method for forming a random microlens array, Patent Document 1 and the like have been proposed. In this method, when producing a mold for the focusing screen, three or more types of indenters having different diameters are used, and a random microlens shape is provided on the metal plate by an indentation method. Then, using this mold, the microlens shape is transferred to the plastic member, and a random-shaped microlens array is formed on the focusing screen.
Japanese Patent Laid-Open No. 11-142609

  However, the indentation method using an indenter presses the indenter as many times as the number of microlenses, so it takes a lot of time to form a large-area microlens array, and there are mechanical limitations, which are on the order of μm. It is difficult to control with accuracy. That is, it is extremely difficult to form a microlens array at random, and reproducibility is poor, so there is a problem in manufacturing stability, efficiency, controllability, and there is a problem that it is actually difficult to implement. .

  SUMMARY OF THE INVENTION An object of the present invention is to provide a focusing screen having a microlens array having a random shape, a focusing screen manufacturing mold that can be used for manufacturing the focusing screen, and an imaging device using the focusing screen.

  In order to solve the above problems, the present invention provides a mold for producing a focusing screen, wherein an inorganic resist film having a plurality of microlens-shaped irregularities is formed on a mold substrate. This mold for producing a focusing screen is formed by a method including a step of forming an inorganic resist film on a mold substrate and a step of exposing and developing the inorganic resist film to form a plurality of microlens-shaped irregularities. It can manufacture suitably. The present invention also provides a focusing screen characterized by having a light-transmitting resin layer onto which a concavity and convexity of the mold for manufacturing a focusing screen is transferred on a light-transmitting substrate.

  In addition, the present invention provides a focusing screen in which an inorganic resist film having a plurality of microlenses is formed on a light-transmitting substrate. This focusing screen can be suitably manufactured by a method having a step of forming an inorganic resist film on a light-transmitting substrate and a step of forming a plurality of microlenses by exposing and developing the inorganic resist film. .

  Furthermore, the present invention provides an imaging apparatus having the focusing plate.

  According to the present invention, it is possible to provide a focusing screen having a microlens array of a random shape, a focusing screen manufacturing mold that can be used for manufacturing the focusing screen, and an imaging device using the focusing screen.

  In the first embodiment of the focusing screen of the present invention, an inorganic resist film having a plurality of microlenses is formed on a translucent substrate. An example of the basic configuration of the focusing screen 101 of the first embodiment is shown in FIGS.

  The light-transmitting substrate 102 may be any substrate that transmits light in the visible light range. For example, a glass substrate, a plastic substrate such as an acrylic resin substrate, or a polycarbonate resin substrate can be used. The “visible light region” here refers to a wavelength range in which image information is required in the imaging apparatus, and is generally a wavelength range of approximately 360 to 830 nm. The transmissivity of the light-transmitting substrate in the visible light region is preferably 10% or less.

  The inorganic resist film 103 preferably has an absorptivity in the visible light region of 10% or less. By having such optical characteristics, a sufficient amount of light can be transmitted through the finder in the visible light range necessary for image formation.

  The inorganic resist film 103 may be a phase change film formed of a phase change material. The “phase change film” referred to here is tungsten oxide (WO) or molybdenum oxide (MoO).

  Further, the inorganic resist film 103 preferably has an absorptance of 10% or more at the wavelength of an exposure light source (360 nm or less) described later. By having such optical characteristics, light energy by exposure can be converted into heat to change the crystal state of the exposed portion, and a microlens can be formed by developing this.

  Note that the optical characteristics of the inorganic resist film 103 can be controlled by controlling the composition of the inorganic resist material constituting the inorganic resist film 103 and controlling the film thickness of the inorganic resist film 103. The composition of the inorganic resist material can be controlled by appropriately adjusting the film forming conditions of the inorganic resist film 103. Further, the film thickness of the inorganic resist film 103 can be controlled by determining the film formation time for obtaining a desired film thickness from the film formation rate (film thickness per unit time) obtained from the film formation conditions.

  As an inorganic resist material for forming the inorganic resist film 103, for example, tungsten oxide (WO) can be used. In addition, molybdenum oxide (MoO), a phase change material obtained by adding Mo to WO, or the like can also be used.

  The film thickness of the inorganic resist film 103 can be set to 0.5 to 5 μm.

  The microlens formed by the inorganic resist film 103 can be formed with various sizes and curvatures, and it is preferable to form a microlens array having a random shape. The plurality of microlenses are preferably formed so as to be adjacent to each other. For example, a microlens array having a random shape can be formed by changing the size of the microlens within a range of 1 to 5 μm in diameter and a radius of curvature within a range of 2 to 15 μm so as to be adjacent to each other. The microlens may be convex or concave.

  Such a focusing screen 101 is more suitable for the step of forming an inorganic resist film 103 on a light-transmitting substrate 102 and the step of exposing and developing the inorganic resist film 103 to form a plurality of microlenses. Can be manufactured. An embodiment for manufacturing the focusing screen 101 will be described in detail in Examples.

  A mold for producing a focusing screen can be obtained by the same configuration as the above focusing screen. That is, in the focusing screen manufacturing mold of the present invention, an inorganic resist film having a plurality of microlens-shaped irregularities is formed on a mold substrate.

  The mold substrate does not need to have translucency, and for example, a metal such as Ni or Al, quartz, or the like can be used, but the above-described translucent substrate can also be used.

  The inorganic resist film preferably has an absorptance of 10% or more at a wavelength of an exposure light source (360 nm or less) described later. By having such optical characteristics, light energy due to exposure can be converted into heat to change the crystal state of the exposed portion, and by developing this, microlens-shaped irregularities can be formed. Further, the inorganic resist film may be a phase change film formed of a phase change material. In addition, although there is no restriction | limiting in the absorptivity in the visible light region of an inorganic resist film, the inorganic resist film whose absorptivity in a visible light region is 10% or less can also be used.

  The optical characteristics of the inorganic resist film can be controlled by controlling the composition of the inorganic resist material constituting the inorganic resist film and controlling the film thickness of the inorganic resist film, as described above.

  As an inorganic resist material for forming the inorganic resist film, for example, tungsten oxide (WO) can be used. In addition, various phase change materials such as molybdenum oxide (MoO) and tellurium oxide (TeO) can also be used.

  The film thickness of the inorganic resist film can be set to 0.5 to 5 μm.

  The microlens-shaped irregularities formed by the inorganic resist film may be irregularities that can form a desired microlens on the focusing screen. The shape of the microlenses constituting the irregularities can be formed with various sizes and curvatures, and it is preferable that the microlens array having a random shape can be formed on the focusing screen. The plurality of microlens shapes are preferably formed adjacent to each other. For example, a microlens array having a random shape on the focusing screen is formed by changing the size of the microlens shape within a range of 1 to 5 μm in diameter and a radius of curvature within a range of 2 to 15 μm so as to be adjacent to each other. Can be formed. In order to produce a focusing screen having a convex microlens, a concave microlens shape obtained by inverting it may be formed. To produce a focusing screen having a concave microlens, What is necessary is just to form the convex microlens shape which reversed.

  Such a mold for producing a focusing screen is more suitable for a step of forming an inorganic resist film on a mold substrate and a step of exposing and developing the inorganic resist film to form a plurality of microlens-shaped irregularities. Can be manufactured. An embodiment for manufacturing the focusing screen manufacturing mold will be described in detail in Examples.

  The second embodiment of the focusing screen of the present invention has a translucent resin layer on which the unevenness of the focusing screen manufacturing mold is transferred on a translucent substrate. An example of the basic configuration of the focusing screen 601 of the second embodiment is shown in FIG.

  The light-transmitting substrate 602 may be any substrate that transmits light in the visible light region as described above. For example, a glass substrate, a plastic substrate such as an acrylic resin substrate, or a polycarbonate resin substrate can be used. . The absorptivity in the visible light region of the light-transmitting substrate 602 is preferably 10% or less.

  The light-transmitting resin layer 603 is not particularly limited as long as it has a light-transmitting property in the visible light region and can be molded by a mold. For example, a resin substrate such as a thermoplastic resin such as an acrylic resin or a polycarbonate resin, a thermosetting resin such as an epoxy resin, or a photocurable resin such as an epoxy resin can be used. In the case where a resin substrate is used as the light-transmitting substrate 602, the same substrate can also be used.

  The film thickness of the translucent resin layer 603 can be set to 0.5 to 5 μm.

  The microlens formed by the translucent resin layer 603 is obtained by inverting the unevenness of the used focusing screen manufacturing mold. That is, microlenses having various sizes and curvatures can be formed by the unevenness of the focusing screen manufacturing mold, and it is preferable to form a microlens array having a random shape. The plurality of microlenses are preferably formed so as to be adjacent to each other. For example, a microlens array having a random shape can be formed by changing the size of the microlens within a range of 1 to 5 μm in diameter and a radius of curvature within a range of 2 to 15 μm so as to be adjacent to each other. The microlens may be convex or concave.

  Such a focusing screen 601 is obtained by bonding the translucent substrate 602 and the translucent resin layer 603 to each other after the unevenness of the focusing plate manufacturing mold is transferred to the translucent resin layer 603. The optical substrate 602 and the translucent resin layer 603 can be preferably manufactured by integral molding. Further, after the light-transmitting substrate 602 and the light-transmitting resin layer 603 are bonded to each other, or the light-transmitting substrate 602 and the light-transmitting resin layer 603 are integrally formed, the above-described focus is applied to the light-transmitting resin layer 603. It can also be suitably manufactured by transferring the unevenness of the plate manufacturing mold. An embodiment for manufacturing the focusing screen 601 will be described in detail in Examples.

  In the focusing screen of the present invention, a microlens is formed on the surface on the emission side of light passing through the focusing screen. This microlens can be formed with various sizes and curvatures, and a focusing screen having a microlens array having a random shape can be produced. As a result, the image displayed on the focus plate is bright, easy to adjust the focus, and can achieve natural blurring, leading to improved operability of the single-lens reflex camera. Such a focusing screen can be easily produced by the focusing screen manufacturing mold of the present invention.

  In the method for manufacturing a focusing screen and the method for manufacturing a focusing screen manufacturing mold according to the present invention, the size and curvature of each microlens formed on the focusing screen can be easily controlled. Therefore, it is possible to produce a focusing screen that matches the user's preference, such as a brighter focusing screen or a focusing screen with a more natural focus adjustment. Furthermore, it has nm-order shape controllability, can be manufactured with extremely high reproducibility, and is excellent in manufacturing stability, efficiency, and controllability.

  The focusing screen of the present invention can be used as a focusing screen for an imaging apparatus such as a movie camera in addition to a single-lens reflex camera.

Example 1
In this example, the focusing screen having the configuration shown in FIG. 1 was produced by the process shown in FIG.

First, as a film forming process, a tungsten oxide (WO) which is a phase change material is formed as an inorganic resist film 103 on a translucent substrate 102 (acrylic resin substrate, absorption rate in visible light region: 3% or less). The film was formed by reactive sputtering. In this reactive sputtering, a tungsten (W) metal target was used, and the Ar gas flow rate was set to 50 sccm, the O ₂ gas flow rate was set to 20 sccm, and the input power was set to 400 W. Further, the film formation time was adjusted from the film formation rate (film thickness per unit time) obtained from the film formation conditions so that the film thickness was 1.0 μm. The obtained inorganic resist film 103 had an absorptance of 3% or less in the visible light region, and an absorptance at a wavelength of 257 nm of an exposure light source to be performed later was 70%.

  Next, as the exposure step, the inorganic resist layer 103 was exposed to draw a fine pattern for forming a microlens. A Deep-UV oscillation argon laser with a wavelength of 257 nm was used as the exposure light source, and a lens with NA = 0.1 was used as the objective lens for determining the exposure spot diameter together with the wavelength. The exposure spot diameter at this time was approximately 2.1 μm in diameter. However, the wavelength of the exposure light source and the NA of the objective lens are not limited thereto. The exposure light source has only to have a wavelength that exhibits light absorption with respect to the inorganic resist film 103, and various gas lasers and various semiconductor lasers can be used. However, in general, since an inorganic resist film tends to have a higher absorptance as the wavelength is shorter, an exposure apparatus using an optical system of a short wavelength light source is suitable. The NA of the objective lens is determined by the size of the microlens formed on the inorganic resist layer 103 and the exposure light source wavelength of the exposure apparatus.

  Here, FIG. 3 shows a block diagram showing a basic configuration of an example of the exposure apparatus. In this exposure apparatus, a fine pattern is drawn by laser exposure on the focusing screen 101 on which the inorganic resist film 103 is formed by a CPU 301 that controls the overall operation.

  FIG. 4 is a schematic diagram of various signal waveforms in this embodiment, and the CPU 301 generates the data signal shown in FIG. In the present embodiment, as shown in FIG. 4C, although the period and time width of each pulse are constant, the peak value of the data signal is not constant, and various peak values are randomly or with a certain regularity. A data signal having a pulse waveform shown is output from the CPU 301. As shown in FIG. 4, the relationship between the data signal and the laser output (LD output) is as follows. The laser is turned on at a high level in the data signal, light is emitted only during the high level, the laser is turned off at the 0 level, The relationship is that the lights remain off only during the 0 level.

  A laser control circuit 302 is connected to the CPU 301. The laser control circuit 302 generates an exposure pattern laser control signal (LD control signal) based on the data signal input from the CPU 301 (FIG. 4B).

  An optical head 300 is connected to the laser control circuit 302. The optical head 300 includes a laser driver 303, a laser (exposure light source) 304 connected to the laser driver 303, and an objective lens 305 that condenses the emitted laser light on the inorganic resist film. The laser driver 303 is supplied with the laser control signal generated by the laser control circuit 302, and the laser driver 303 generates a laser driving current based on the supplied laser control signal. Then, the laser 304 is driven to emit light so as to show the laser output as shown in FIG. In this embodiment, FIGS. 4A, 4B, and 4C are basically similar waveforms. Then, the emitted laser beam is condensed on the inorganic resist film by the objective lens 305 and exposed, thereby drawing a fine pattern.

  As described above, a laser control signal having a pulse waveform having various levels based on the data signal is generated, and thereby the laser 304 is driven to emit light, whereby the laser output has a pulse waveform indicating various powers. And by exposing with such a laser output, after the exposure, the altered area | region is drawn as a pattern which has various magnitude | sizes. That is, when the pulse has a large laser output, the exposed portion (microlens) is large, and when the pulse has a small laser output, the exposed portion (microlens) is small.

  Further, when the laser output is relatively large and the power is controlled to form a random shape with a large microlens, a bright focusing plate can be produced. In addition, when a microlens is formed by power control with a wide dynamic range from a small laser output to a large laser output, the randomness of the microlens increases and a more natural blur condition is realized.

  In this embodiment, as a data signal for determining the microlens shape, exposure for one microlens is performed by one pulse emission. In order to further improve the shape controllability, it is possible to use a data signal for exposure for forming one microlens by a series of continuous pulse emission.

  By controlling the laser output based on the data signal as described above, it is possible to control a fine pattern drawn on the inorganic resist and obtain microlenses having various shapes with high accuracy.

  On the other hand, the focusing screen 101 on which the inorganic resist film 103 is formed moves at a relatively constant speed relative to the light spot on the inorganic resist film 103 by the objective lens 305. That is, the light spot is scanned linearly on the focusing screen 101 at a constant speed. When a light spot arrives at one end of the focusing screen 101, exposure is performed by scanning the light spot in the opposite direction at a predetermined distance (scan line interval) perpendicular to the scanning direction. .

  Although the light spot is scanned linearly, it is also possible to scan the light spot at a constant speed in a spiral shape. In other words, the focusing screen 101 is rotated to scan the light spot in a spiral shape, and the light spot is gradually moved in the radial direction toward the outer peripheral side or the inner peripheral side at a constant speed. It can expose so that an interval may become a predetermined distance.

  With the exposure apparatus as described above, the inorganic resist film 103 on the focusing screen 101 can be exposed over a wide range, and a desired fine pattern can be drawn. In addition, by exposing a large area so that multiple surfaces can be taken and cutting it out to a required size after exposure, it is possible to shorten the time required for preparation before exposure and to efficiently produce it.

  In this example, the light spot was linearly scanned at a speed of 1.0 m / s using the above exposure apparatus. The data signal input to the laser control circuit 302 was as shown in FIG. 4C, and was performed with a one-level pulse width of 0.1 μs and a pulse period of 700 KHz. Regarding the laser output, the crest value (power) of each laser pulse in FIG. 4A was set to a random value between 300 and 600 mW. Further, the interval between two adjacent scanning lines by the laser beam was set to 1.4 μm.

Then, as a development process, the inorganic resist film 103 on which a fine pattern was drawn by exposure was developed with a tetramethylammonium hydroxide solution, which is an alkaline developer, and the exposed portion 204 was removed. That is, the inorganic resist film of this embodiment is a positive resist, and a concave microlens as shown in FIG. 1 is formed. This is because, as a result of observing the state of the exposure unit 204 with a TEM or the like, there is a region in which the crystal structure is altered in a hemispherical shape along the temperature distribution, and the altered region is removed when developed, This is because a microlens-shaped recess is formed. As the alkaline developer, an inorganic alkaline aqueous solution such as KOH, NaOH, Na ₂ CO ₃ or the like can be used.

  Through the above steps, a focusing screen on which concave microlenses were formed could be manufactured. Each microlens formed on the focusing screen has various sizes and curvatures, and has a diameter of approximately 1.5 to 2.2 μm and a radius of curvature of approximately 3 to 5 μm, and is formed in a random arrangement.

  When this focusing screen is applied to a single-lens reflex digital camera and focus adjustment is performed, the image when looking through the viewfinder is bright and natural blurring has been achieved, improving the focus adjustment operability. did.

(Example 2)
In this example, the focusing screen having the configuration shown in FIG. 5 was produced by the process shown in FIG.

  In the exposure process, except that the crest value (power) was fixed at 450 mW, the pulse time width was fixed at 0.1 μs, and the data signal with a random pulse emission interval (pulse period) was input to the laser control circuit 302. A focusing screen was prepared in the same manner as in Example 1. The obtained focusing screen had a configuration as shown in FIG. 5, and concave microlenses having a diameter of about 1.9 μm and a curvature radius of about 4 μm were formed in various arrangements.

  When this focusing screen is applied to a single-lens reflex digital camera and focus adjustment is performed, the image when looking through the viewfinder is bright and natural blurring has been achieved, improving the focus adjustment operability. did.

(Example 3)
In this example, a focusing screen manufacturing mold 701 was manufactured by the process shown in FIG. 7, and a focusing screen having the configuration shown in FIG. 6 was manufactured using the mold.

First, on the mold substrate 702 (Ni), a tungsten oxide (WO) that is a phase change material was formed as an inorganic resist film 703 by reactive sputtering. In this reactive sputtering, a tungsten (W) metal target was used, and the Ar gas flow rate was set to 60 sccm, the O ₂ gas flow rate was set to 20 sccm, and the input power was set to 400 W. Further, the film formation time was adjusted from the film formation rate (film thickness per unit time) obtained from the film formation conditions so that the film thickness was 1.0 μm. The obtained inorganic resist film 703 had an absorptance of 80% at a wavelength of 257 nm of an exposure light source to be performed later.

  Next, the inorganic resist film 703 was exposed to draw a fine pattern for forming microlens-shaped irregularities. This exposure was performed in the same manner as in Example 1, using the same exposure apparatus as in Example 1.

Then, the inorganic resist film 703 on which a fine pattern was drawn by exposure was developed with a tetramethylammonium hydroxide solution, which is an alkaline developer, and the exposed portion 704 was removed. That is, the inorganic resist film of this embodiment is a positive resist, and concave microlens-shaped irregularities 705 are formed. As the alkaline developer, an inorganic alkaline aqueous solution such as KOH, NaOH, Na ₂ CO ₃ or the like can be used.

  Through the above steps, a focusing screen manufacturing mold in which concave and convex portions having a concave microlens shape were formed. The size and curvature of each microlens shape forming the unevenness formed on this focusing screen manufacturing mold vary, the diameter is about 1.6 to 2.4 μm, the curvature is about 3 to 5 μm, The distance was approximately 1.4 μm.

  By attaching the obtained focusing screen manufacturing mold to an injection molding machine and molding an acrylic resin, the translucent resin layer 603 to which the microlens shape is transferred (thickness 100 μm, absorption in the visible light region: 3) % Or less). Then, the translucent resin layer 603 and the translucent substrate 602 (acrylic resin substrate, absorptance in the visible light region: 3% or less) were adhered to each other with an acrylic adhesive to produce a focusing screen 601.

  When this focusing screen is applied to a single-lens reflex digital camera and focus adjustment is performed, the image when looking through the viewfinder is bright and natural blurring has been achieved, improving the focus adjustment operability. did.

  In this embodiment, the focusing screen manufacturing mold 701 including the inorganic resist film 703 on which the microlens-shaped irregularities 705 are formed and the mold substrate 702 is used as a mold for molding the focusing screen 601. May be used as the master of the focusing screen. By performing the conventional electroforming process using Ni or the like on this master, a mold composed only of Ni having higher strength can be obtained.

It is a schematic diagram which shows the basic composition of 1st Embodiment of the focusing screen which concerns on this invention. It is a schematic diagram which shows the manufacturing process of the focusing screen in Examples 1 and 2. It is a block diagram which shows the basic composition of the exposure apparatus used in Examples 1-3. It is a figure which shows the relationship between the laser output in the exposure process of Example 1 and 3, a laser control signal, and a data signal. It is a schematic diagram which shows the basic composition of 1st Embodiment of the focusing screen which concerns on this invention. It is a schematic diagram which shows the basic composition of 2nd Embodiment of the focusing screen which concerns on this invention. 6 is a schematic diagram illustrating a focusing plate manufacturing process according to Embodiment 3. FIG.

Explanation of symbols

101 Focusing Plate 102 Translucent Substrate 103 Inorganic Resist Film 204 Exposure Unit 301 CPU
302 Laser Control Circuit 303 Laser Driver 304 Laser 305 Objective Lens 601 Focusing Plate 602 Translucent Substrate 603 Translucent Resin Layer 701 Focusing Plate Manufacturing Mold 702 Type Substrate 703 Inorganic Resist Film 704 Exposure Portion 705 Microlens Concavity and Concavity

Claims (6)

  A mold for producing a focusing screen, wherein an inorganic resist film having a plurality of microlens-shaped irregularities is formed on a mold substrate. Forming an inorganic resist film on the mold substrate;
And a step of forming a plurality of microlens-shaped irregularities by exposing and developing the inorganic resist film.   A focusing screen, comprising: a translucent resin layer onto which a concavity and convexity of the focusing screen manufacturing mold according to claim 1 is transferred.   A focusing screen, wherein an inorganic resist film having a plurality of microlenses is formed on a translucent substrate. Forming an inorganic resist film on the translucent substrate;
And a step of forming a plurality of microlenses by exposing and developing the inorganic resist film.   An imaging apparatus comprising the focusing screen according to claim 3.

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