Patent Description:
As a device that forms stereoscopic images using light (scattering light) emitted from the surface of an object, e.g., there is a stereoscopic-image-forming device (an optical-image-forming device) set forth in Patent Literature <NUM>.

The image-forming device of Patent Literature <NUM> includes first and second light control panels formed by aligning with a constant pitch a large number of band-like light-reflective surfaces made of metal reflective surfaces inside of two transparent flat plates. The band-like light-reflective surfaces are vertically aligned over the thickness direction of each of the transparent flat plates. The image-forming device is configured by bonding together the first and second light control panels with respective one surface sides of the first and second light control panels facing each other such that the respective light-reflective surfaces of the first and second light control panels are orthogonally crossed.

When producing the above-mentioned first and second light control panels, a large number of plate-shaped transparent synthetic resin plates or glass plates (hereinafter, referred also as to "transparent plates") having a same constant thickness and each having a metal reflective surface formed on one surface side are laminated in a manner where the metal reflective surfaces are disposed in one side to produce a laminated body, and then the first and second light control panels are cut out from the laminated body such that cut planes become perpendicular to the metal reflective surfaces.

As a result, a large deposition furnace is necessary when working on forming the metal reflective surfaces on the transparent plates. Besides, forming the metal reflective surfaces requires to repeat over <NUM> times a series of operations: putting one or a small numbers of transparent plate(s) in the deposition furnace; executing deposition after deaerating the furnace to have a high vacuum state; opening to atmospheric pressure and taking the deposited transparent plate(s) out from the furnace, and it is an extremely burdensome and time-consuming work. Additionally, it is poor in workability and manufacturing efficiency because this requires forming the laminated body by laminating the metal deposited transparent plates, cutting out the first and second light control panels from the laminated body by cutting the laminated body into an extremely thin predetermined thickness, and also doing other operations such as polishing the cut planes (in both sides) of the first and second light control panels, or else.

To cope with this, a method as disclosed in Patent Literature <NUM> is suggested. In the method, two light control panels each including a concave-convex plate material, on one surface side of which quadrilateral-cross-section grooves are formed by parallel banks and on opposing lateral surfaces of the grooves light-reflective parts are formed, are prepared, and then the two light control panels are made to face to each other such that the respective light-reflective parts thereof are orthogonally crossed or crossed.

However, there is a problem that demolding becomes extremely difficult if the height of the banks of the concave-convex plate material is high (that is, the depth of the grooves is deep) when the concave-convex plate material is formed by injection-molding. Furthermore, forming mirror surfaces on the lateral surfaces of the parallel grooves is difficult even by using technology of Patent Literature <NUM>, and thus, there is a problem that irregularity in the shape of the products frequently occurs.

Patent Literature <NUM> discloses a manufacturing method of light control panels used for an optical imaging device, including: a first step of forming on one side of a transparent plate material a large number of parallel grooves each having opposed parallel lateral faces and flat bottom face by making the transparent plate material go through between a groove roller with a large number of parallel grooves formed in the circumferential direction and a flat roller with a flat surface; a second step of forming light reflective portions by conducting a mirror surface treatment that forms light reflective surfaces only on the opposite lateral faces of the parallel grooves; and a third step of preparing two transparent plate materials each having the parallel grooves formed on its one side and overlapping the two transparent plate materials in a manner where the parallel grooves of one of the two transparent plate materials and the parallel grooves of the other one of the two transparent plate materials are orthogonally crossed.

In the stereoscopic-image-forming device of Patent Literature <NUM>, the first and second light control portions are formed respectively on one side and the other side of a transparent plate material, the first light control portion includes band-like light reflective surfaces standing upright and arranged in parallel, the second light control portion includes band-like light reflective surfaces standing upright and arranged in parallel, and the band-like light reflective surfaces of the first light control portion and the band-like light reflective surfaces of the second light control portion are so disposed as to be orthogonally crossed in a plan view. The first and second light control portions are produced by a method where the first light control portion is formed on the one side of the transparent plate material and after that the second light control portion is formed on the other side.

Patent Literature <NUM> discloses an improved multi-depth display apparatus and a method for displaying images at at least two different perceived depths, using a single display. The multi-depth display apparatus comprises a display panel comprising a plurality of pixels arranged to display at least a first image and a second image; and a direction changing layer arranged so that light forming said first and second images enters the direction changing layer and then exits the direction changing layer.

The present invention has been made in consideration of the above circumstances, and has as its object to provide a production method for a stereoscopic-image-forming device and a stereoscopic-image-forming device using the production method, which is capable of easily producing the first and second light control panels and the stereoscopic-image-forming device body formed by integrating the first and second light control panels, and of obtaining clearer stereoscopic images.

The invention for which protection is sought is defined by the claims.

A production method for a stereoscopic-image-forming device according to the claimed invention comprises:.

According to the claimed invention, in the second step the mirror surfaces are formed by sputtering, metal deposition, metal microparticle spraying, or ion beam irradiation toward the vertical surfaces from a direction along the inclined surfaces in a manner where the inclined surfaces become in shadow. This makes it possible to prevent to the utmost the mirror surfaces from being formed on the inclined surfaces of the grooves, thereby the mirror surfaces can be selectively formed on the vertical surfaces of the grooves.

According to an embodiment of the claimed invention, the inclined surfaces may be flat surfaces. This makes it possible to further prevent the mirror surfaces from being formed on the inclined surfaces of the grooves, thereby the mirror surfaces can be selectively formed on the vertical surfaces of the grooves.

According to another embodiment, it is preferable that an annealing treatment for removing residual stress be applied to the molded preform after being formed. This makes it possible to produce a stereoscopic-image-forming device with less deformation.

A production method for a stereoscopic-image-forming device and a stereoscopic-image-forming device according to the present application use a molded preform produced by any one of press-molding, injection-molding, and roll-molding. A large number of grooves formed in parallel each have an inclined surface and a vertical surface. Each of the grooves becomes wider toward the opening, and thus, molding and demolding become easier. Therefore, a stereoscopic-image-forming device, which aspect ratio defined by (the height of the groove) / (the width of the groove) is relatively high, can be produced at a relatively low cost.

Here, a metal coating can be selectively formed on each of the vertical surfaces by sputtering, metal deposition, metal microparticle spraying, or ion beam irradiation.

Furthermore, by making the inclined surfaces be flat surfaces, or more effectively, concave surfaces recessed inward, mirror surfaces can be prevented to the utmost from being formed on the inclined surfaces of the grooves.

Subsequently, a description of a stereoscopic-image-forming device and a production method for the same follows with reference to the accompanying drawings.

As shown in <FIG>, <FIG>, a stereoscopic-image-forming device <NUM> includes a top-bottom pair of first and second light control panels (parallel light-reflective panels) <NUM>. Note that since the first and second light control panels <NUM> have a same configuration, they have same reference signs assigned.

As shown in <FIG>, <FIG>, the first and second light control panels <NUM> each include a transparent plate material <NUM>, and the transparent plate material <NUM> has on its one side (front side) (i.e. the bottom for the first light control panel <NUM>, the top for the second light control panel <NUM>) triangle-cross-section grooves <NUM> and triangle-cross-section protruded strips <NUM> formed between the grooves <NUM>. The grooves <NUM> each have a vertical light-reflective surface <NUM> (a mirror surface) and an inclined surface (a non-light-reflective surface, and preferably a light transmitting surface) <NUM>. The grooves <NUM> and the protruded strips <NUM> of the first and second light control panels <NUM> are respectively provided in large numbers and in parallel with a constant pitch. Accordingly, the first and second light control panels <NUM> each have a group of band-like light-reflective surfaces standing upright and spaced in parallel.

A transparent resin <NUM> is filled up into the grooves <NUM>, and a filled surface <NUM> is parallel to a back side surface <NUM> of the first and second light control panels <NUM> (e.g. transparent plate materials <NUM>), respectively. The first and second light control panels <NUM> are disposed with a front side surfaces <NUM> of the first and second light control panels <NUM> (refer to <FIG>) being abutted on or proximate to each other in a manner where the light-reflective surfaces <NUM> of the first and second light control panels <NUM> are orthogonally crossed (or, e.g., crossed within a range of <NUM> to <NUM> degrees, more preferably <NUM> to <NUM> degrees) in a plan view. The first and second light control panels <NUM> are bonded together via e.g. a transparent adhesive agent (resin) and integrated.

It is preferable that the transparent resin constituting the shape of the first and second light control panels <NUM> and the transparent resin <NUM> filled up into the grooves <NUM> be the same resin; however, they may be different kinds of transparent resins. In a case of using different kinds of transparent resins, it is preferable that their refractive indexes (η) be identical or approximate. In other words, in a case of using different transparent resins, it is preferable that a transparent resin which refractive index (η2) is identical or nearly equal to the refractive index (η1) of the transparent resin constituting the shape of the first and second light control panels <NUM> (transparent plate materials <NUM>) according to the claimed invention, η2 is within a range of (<NUM> to <NUM>)×η1) be used as the transparent resin filled up into the grooves (It is also the case in embodiments below).

Incidentally, regarding the first and second light control panels <NUM> in <FIG>, h2/h1 is e.g. preferably <NUM> to <NUM>. Here, on a definition that h1 is the thickness of the transparent plate material <NUM> and h2 is the height of the protruded strips <NUM> (i.e. the vertical light-reflective surfaces <NUM>), it is practical that (h1+h2) is within a range of <NUM> to <NUM>, and h1 is e.g. equal to or more than <NUM>; however, the present invention is not limited to the mentioned numerical values. According to the claimed invention, an angle θ1 between the vertical light-reflective surface <NUM> and the inclined surface <NUM> is within a range of <NUM> to <NUM> degrees; however, in examples not according to the claimed invention, the angle Θ1 may be changed depending on the values of h1 and h2. Additionally, it is preferable that the aspect ratio (h2/w), that is, a ratio between the width (pitch) w of the groove <NUM> and the height h2 of the vertical light-reflective surface <NUM> be approximately <NUM> to <NUM> (more preferably, <NUM> to <NUM>), and this makes it possible to obtain higher vertical light-reflective surfaces <NUM>.

At each of the corner portions (bottom portions) of the triangle-cross-section grooves <NUM> that forms an acute angle, a micro flat portion <NUM> is provided, and at each of the corner portions (top portions) of the triangle-cross-section protruded strips <NUM> that forms an acute angle, a micro flat portion <NUM> is provided. The each width of the micro flat portions <NUM>, <NUM> is preferably <NUM> to <NUM> times the bottom width (w) of the triangle-cross-section grooves <NUM> and the triangle-cross-section protruded strips <NUM>. Incidentally, the widths of the micro flat portions <NUM>, <NUM> may be identical or different. By providing the micro flat portions <NUM>, <NUM>, the products become resistant to flaws, and besides, the accuracy of the products increases. Note that since the widths of the micro flat portions <NUM>, <NUM> are narrow, it is explained, with the micro flat portions <NUM>, <NUM> left out of account, presuming that the cross-section of each of the grooves <NUM> and protruded strips <NUM> is a triangle (It is also the case in embodiments below).

The vertical light-reflective surfaces <NUM> are formed by selectively performing a mirror surface treatment (mirror-finishing treatment) to vertical surfaces <NUM> of a molded preform <NUM> made from a transparent resin (described below) (refer to <FIG>). The mirror surface treatment is usually selectively performed by metal deposition, sputtering, metal microparticle spraying, or ion beam irradiation (hereinafter, may be referred to as "sputtering or other methods"). The inclined surfaces <NUM> remain as they are as a part of the molded preform <NUM> that is transparent, and each have a well-light-transmissible homogeneous flat surface as shown in <FIG>.

Although the inclined surfaces <NUM> are flat surfaces as described above, the inclined surfaces <NUM> includes cases even where the cross-section is a concave surface recessed inward <NUM>, <NUM>, and the cross-section is a concave surface making use of a part of a polygon as shown in <FIG>, not in accordance with the claimed invention. A surface which cross-section is a straight line or inside the straight line, and having a constant downward gradient from the top portion of the protruded strip to the bottom portion of the groove, is treated as an inclined surface (It is also the case in embodiments below).

The concave surface <NUM> shown in <FIG> is configured by two flat surfaces <NUM>, <NUM> in a manner where an angle θ2 formed by the flat surfaces <NUM>, <NUM> becomes less than <NUM> degrees (e.g. <NUM> to <NUM> degrees, preferably the lower limit is <NUM> degrees and the upper limit is <NUM> degrees). Here, although the concave surface <NUM> is configured by the two flat surfaces <NUM>, <NUM>, the concave surface may be configured by three or more of flat surfaces. In this case, angles formed by the flat surfaces next to each other may be identical or different.

The concave surface <NUM> shown in <FIG> is configured by a curved surface which cross-section is bent or in a state of a circular arc.

Note that the concave surface is not limited to the above-mentioned shapes, but may be configured by combining a flat surface and a curved surface.

As a result, by performing sputtering or other methods to the vertical surfaces <NUM> along the inclined surfaces <NUM> with an angle equal to or beyond the cross-section inclination angle Θ1 of the flat inclined surface <NUM> (e.g. <NUM> to <NUM> degrees) shown in <FIG>, forming mirror surfaces on the concave surfaces <NUM> or <NUM> can be avoided. Accordingly, the recessed amount of the concave surfaces <NUM>, <NUM> to the inclined surfaces <NUM> may variously changed depending on conditions of the sputtering or other methods.

By forming the vertical light-reflective surfaces <NUM> as explained above, in <FIG>, lights L1 and L2 from an object obliquely entering from lower left side of the stereoscopic-image-forming device <NUM> respectively reflect at P1 and P2 of the lower vertical light-reflective surface <NUM>, further reflect at Q1 and Q2 of the upper vertical light-reflective surface <NUM>, and form a stereoscopic image in space on one side (the top side) of the stereoscopic-image-forming device <NUM>. Note that, front sides (left sides in <FIG>) of metal reflective films (metal coatings) <NUM> formed on the vertical surfaces <NUM> by the mirror surface treatment are used as the vertical light-reflective surfaces <NUM> of the first and second light control panels <NUM>; however, as shown in <FIG>, back sides (right sides in <FIG>) of the metal reflective films <NUM> may be used as the vertical light-reflective surfaces <NUM>.

In other words, as shown in <FIG>, lights L3 and L4 from an object obliquely entering from lower right side of the stereoscopic-image-forming device <NUM> respectively enter into the lower transparent plate material <NUM> at R1 and S1, reflect at R2 and S2 of the lower vertical light-reflective surface <NUM>, further reflect at R3 and S3 on the upper vertical light-reflective surface <NUM>, exit from R4 and S4 of the upper transparent plate material <NUM>, and form a stereoscopic image in space on the top side (one side) of the stereoscopic-image-forming device <NUM>.

In the operation of the stereoscopic-image-forming device <NUM>, when the lights enter into the transparent plate material <NUM> from the air and when the lights exit from the transparent plate material <NUM> into the air, a refraction phenomenon or, according to the circumstances, a total reflection phenomenon of the lights may occur. Therefore, it is necessary to use the stereoscopic-image-forming device <NUM> while taking in consideration the possibility of occurrence of these phenomena. (It is also the case in embodiments below). Incidentally, the inclined surfaces <NUM> become light transmissive surfaces as they are.

In the stereoscopic-image-forming device <NUM>, the cross-section of each of the protruded strips and grooves therebetween may be a rectangle or square shape; however, in this case, if the height-to-width ratio (height/width) is equal to or more than <NUM>, the production (especially, the demolding) becomes difficult. Since each of the grooves <NUM> formed between the protruded strips <NUM> has a triangle-cross-section that width becomes narrower toward the bottom side, the production of the molded preform <NUM> by injection-molding becomes easier.

Subsequently, a production method for the stereoscopic-image-forming device <NUM> is explained with reference to <FIG>. Note that since the production methods for the second light control panel <NUM> and the first light control panel <NUM> are the same, the production method for the first light control panel <NUM> is mainly explained.

As shown <FIG>, the molded preform <NUM>, where the triangle-cross-section grooves <NUM> each having the vertical surface <NUM> and the inclined surface <NUM> and the protruded strips <NUM> formed by the grooves <NUM> next to each other are respectively arranged in parallel on one side (top side) of the transparent plate material <NUM>, is produced by any one of press-molding, injection-molding and roll-molding.

In this case, it is preferred that as the material of the molded preform <NUM>, a thermoplastic resin such as polymethylmethacrylate (acrylic resin), amorphous fluororesin, PMMA, COP, optical polycarbonate, fluorine based polyester, polyether sulfone or the like be used. The dimensions of the molded preform <NUM> are approximately the same as the dimensions of the light control panel <NUM>. As described above, each of the grooves <NUM> is tapered so as to widen outwardly; thus, demolding efficiency of the molded preform <NUM> is excellent and the vertical surfaces can be easily obtained even if they are long. Incidentally, the annealing treatment for removing the residual stress having occurred while molding is applied to the molded preform <NUM>. The annealing treatment is performed by, e.g., placing the molded preform <NUM> in an electric furnace, a hot air dryer or a hot water bath (heated solvent) for a predetermined time length (It is also the case in embodiments below; hereinbefore: a first step).

Next, the mirror surfaces (the vertical light-reflective surfaces <NUM>) are selectively formed only on the vertical surfaces <NUM> by a method shown in <FIG>, e.g., by sputtering. The sputtering is a technology in which an inert gas (mainly argon) is introduced in a vacuum, a negative voltage is applied to a target to cause a glow discharge, the inert gas atoms are ionized (or, in a non-ionized atomic state), the gas ions are bombarded to the surface of the target at a high speed, metal particles of film forming material constituting the target (e.g. aluminum, silver, nickel, or else) are ejected, and the ejected metal particles are adhered and deposited with sufficient momentum onto a substrate (in this case, the vertical surfaces <NUM>). When the sputtering (including the metal microparticle spraying) is performed toward the vertical surfaces <NUM> in a manner where the gas flow <NUM> is along the inclined surfaces <NUM> and the inclined surfaces <NUM> become in shadow, the film forming material is unlikely to adhere onto the inclined surfaces <NUM>, and thus, the film forming material is adhered only onto the vertical surfaces <NUM>. The smaller the angle Θ1 of the inclined surfaces <NUM> is, the more excellent the selective adherence efficiency becomes. Also, the selective adherence efficiency becomes even more excellent if adopting the concave surfaces <NUM> or <NUM> shown in <FIG>. The metal reflective films (metal coatings) <NUM> are formed on the surfaces of the vertical surfaces <NUM> as described above, thereby the vertical surfaces <NUM> become the vertical light-reflective surfaces <NUM>, and the molded preform becomes an intermediate preform <NUM>. Incidentally, forming the protruded strips having the concave surfaces is easy.

As other ways to selectively form the mirror surfaces on the vertical surfaces <NUM>, there are a way of performing the metal deposition (PVD or CVD) only to the vertical surfaces <NUM> after masking all the inclined surfaces <NUM>, and a way of accelerating the metal particles using magnetic field in the metal deposition. There is also a way where, firstly, a film coating treatment that can be removed in a post-process is applied only to the inclined surfaces <NUM>, secondly, any one of the metal deposition, sputtering, metal microparticle spraying, or ion beam irradiation is performed to the vertical surfaces <NUM> and the surface of the coated film, and then the coated film is removed to expose the transparent inclined surfaces <NUM>. Incidentally, as the coating film, it can be selected from coating films that are removable (i) by chemicals (solvents), (ii) by ultraviolet irradiation from the back side, or (iii) by heating up to a temperature with which the molded preform does not deform (Hereinbefore: a second step).

Subsequently, as shown in <FIG>, in a state of vacuum the transparent resin <NUM> is filled up into the grooves <NUM> of the intermediate preform <NUM>, and a flattening treatment to the filled surface <NUM> is applied to form a surface (a top surface) <NUM>. As the transparent resin <NUM> put in the grooves <NUM> in this case, it is preferable that a transparent resin that is the same as the material of the molded preform <NUM> or a transparent resin having a refractive index close to that of the molded preform <NUM> be used. The position of the surface <NUM> may be matched the level of the micro flat portions <NUM>. The first light control panel <NUM> is thereby completed. Incidentally, the second light control panel <NUM> is produced with the same configuration and steps as the first light control panel <NUM>.

After that, as shown in <FIG>, the respective surfaces <NUM> of the first and second light control panels <NUM> are bonded together (overlapped each other) in vacuum in a manner where the respective sides (the one sides, the front sides), on which the protruded strips <NUM> are formed, of the first and second light control panels <NUM> face to each other and abut on or proximate to each other such that the respective light-reflective surfaces <NUM> of the first and second light control panels <NUM> are orthogonally crossed or crossed (e.g. within a range of <NUM> to <NUM> degrees) in a plan view. The distance C between the micro flat surfaces <NUM> on the protruded strips <NUM> of the first light control panel <NUM> and the micro flat surfaces <NUM> on the protruded strips <NUM> of the second light control panel <NUM> is, e.g., exceeding <NUM>, and equal to or less than <NUM>, approximately. The stereoscopic-image-forming device <NUM> is thereby completed. Note that, the first and second light control panels <NUM> are bonded together in a manner where the respective sides on which the protruded strips <NUM> are provided abut on or proximate to each other; however, the stereoscopic-image-forming device may be configured by making the respective transparent plate materials <NUM> (the back sides) abut on each other, or by making the side on which the protruded strip <NUM> are provided of the first light control panel <NUM> and the transparent plate material <NUM> of the second light control panel <NUM> (or vice versa) abut on each other (hereinbefore: a third step).

Next, with reference to <FIG>, a stereoscopic-image-forming device <NUM> and a production method for the same according to the present invention will be explained below. In the case of the stereoscopic-image-forming device <NUM> according to <FIG>, the first and second light control panels <NUM> are separately produced and overlapped each other to form the stereoscopic-image-forming device <NUM>. However, in the case of the stereoscopic-image-forming device <NUM>, grooves <NUM>, <NUM> and protruded strips <NUM>, <NUM> formed on the front and back surfaces (both surfaces) of a transparent plate material <NUM> are integrally formed by dies.

In the stereoscopic-image-forming device <NUM>, triangle-cross-section grooves <NUM> (first grooves) each having a vertical surface <NUM> and an inclined surface <NUM> and triangle-cross-section protruded strips <NUM> (first protruded strips) formed by the grooves <NUM> next to each other are respectively arranged in parallel on one side of the transparent plate material (having a thickness h3) <NUM> positioned in the middle. Additionally, triangle-cross-section grooves <NUM> (second grooves) each having a vertical surface <NUM> and an inclined surface <NUM> and triangle-cross-section protruded strips <NUM> (second protruded strips) formed by the grooves <NUM> next to each other are respectively arranged in parallel on the other side of the transparent plate material <NUM>. A molded preform <NUM> is produced by any one of press-molding, injection-molding and roll-molding such that the grooves <NUM> formed on one side of the transparent plate material <NUM> and the grooves <NUM> formed on the other side of the transparent plate material <NUM> are orthogonally crossed or crossed in a plan view with an angle of e.g. <NUM> to <NUM> degrees, preferably <NUM> to <NUM> degrees. The molded preform <NUM> is made from a transparent resin (first transparent resin) as same as the molded preform <NUM>.

At the bottom portions (corner portions) of the triangle-cross-section grooves <NUM>, <NUM> and at the top portions (corner portions) of the protruded strips <NUM>, <NUM>, micro flat portions (not shown in Figs. ) are provided as same as the above-described stereoscopic-image-forming device <NUM>. The material, production method, and specifications (dimensions h2 and Θ1) of the molded preform <NUM> are the same as those of the stereoscopic-image-forming device <NUM>. However, in this embodiment the thickness (h3) of the transparent plate material <NUM> is twice the thickness (h1) of the transparent plate material <NUM> (hereinbefore: a first step).

Subsequently, vertical light-reflective surfaces <NUM>, <NUM> that are the mirror surfaces are selectively formed by performing the mirror surface treatment only to vertical surfaces <NUM> of the grooves <NUM> and vertical surfaces <NUM> of the grooves <NUM> respectively provided on the both sides of the transparent plate material <NUM>, as mentioned above, by metal deposition, sputtering, or according to the circumstances, spraying metal microparticles or ion beam irradiation (an intermediate molded preform, hereinbefore: a second step). The stereoscopic-image-forming device <NUM> in a state of a flat plate having the first and second light control panels which exposed surfaces are flat surfaces formed on the front and back sides thereof is made by filling up the grooves <NUM>, <NUM> of the intermediate molded preform with a transparent resin <NUM>, <NUM> (the second transparent resin) and applying the flattening treatment to the filled surfaces (hereinbefore: a third step).

As the mirror surface treatment to form the mirror surfaces only on the vertical surfaces <NUM> of the grooves <NUM> and the vertical surfaces <NUM> of the grooves <NUM>, there are a way of sequentially or simultaneously performing the metal deposition or the sputtering to the front and back surfaces of the molded preform <NUM> and other ways.

In <FIG> that shows the stereoscopic-image-forming device <NUM> in a plan view (the stereoscopic-image-forming device <NUM> is also the same), the vertical light-reflective surfaces <NUM> are arranged with an angle of <NUM> to <NUM> degrees in a plan view with respect to an outer frame <NUM> having a shape of a rectangle or a square. Thereby, it is possible to form a bigger stereoscopic image by effectively utilizing the small-sized stereoscopic-image-forming device since the stereoscopic image is formed via the upper and lower vertical light-reflective surfaces <NUM> arranged being orthogonally crossed or crossed in a plan view.

The present invention is not limited to the above-mentioned embodiments, and the present invention is applied also in the cases where the elements of or the production methods for the stereoscopic-image-forming device according to each of the embodiments are combined to configure or produce a stereoscopic-image-forming device. Note that in the embodiments above, the vertical light-reflective surfaces (mirror surfaces) are formed on the both sides of each of the metal coatings.

In the present invention explained above, the flattening treatment includes the cases of forming by cutting or polishing as well as pushing by presses or else and molding by dies.

The production method for a stereoscopic-image-forming device and the stereoscopic-image-forming device according to the present invention enable a stereoscopic-image-forming device which aspect ratio is relatively high to be easily and inexpensively produced. Therefore, the stereoscopic-image-forming device can be effectively utilized for appliances that require an image (e.g. medical appliances, home appliances, motor vehicles, aircrafts, vessels, or else).

Claim 1:
A production method for a stereoscopic-image-forming device (<NUM>) characterized by comprising:
a first step of producing a molded preform (<NUM>) made from a first transparent resin by injection-molding, the molded preform (<NUM>) including triangle-cross-section first and second grooves (<NUM>, <NUM>) formed respectively on both sides of a transparent plate material (<NUM>), the molded preform (<NUM>) including triangle-cross-section first and second protruded strips (<NUM>, <NUM>) formed respectively on the both sides of the transparent plate material (<NUM>), the first and second grooves (<NUM>, <NUM>) each having a vertical surface (<NUM>, <NUM>) and an inclined surface (<NUM>, <NUM>) with an angle (θ1) therebetween of <NUM> to <NUM> degrees, the first protruded strips (<NUM>) being formed by the first grooves (<NUM>) next to each other, the second protruded strips (<NUM>) being formed by the second grooves (<NUM>) next to each other, the first and second grooves (<NUM>, <NUM>) formed respectively on the both sides of the transparent plate material (<NUM>) being arranged so as to be orthogonally crossed in a plan view;
a second step of forming mirror surfaces (<NUM>, <NUM>) selectively on the vertical surfaces (<NUM>, <NUM>) of the first and second grooves (<NUM>, <NUM>) provided on the both sides of the molded preform (<NUM>); and
a third step of filling up a second transparent resin (<NUM>, <NUM>) into the first and second grooves (<NUM>, <NUM>) after performing the second step, and further applying a flattering treatment to the surface of the filled second transparent resin (<NUM>, <NUM>),
wherein in the second step the mirror surfaces (<NUM>, <NUM>) are formed by sputtering, metal deposition, metal microparticle spraying, or ion beam irradiation toward the vertical surfaces (<NUM>, <NUM>) from a direction along the inclined surfaces (<NUM>, <NUM>) in a manner where the inclined surfaces (<NUM>, <NUM>) become in shadow, and
wherein a refractive index η2 of the second transparent resin (<NUM>, <NUM>) is within a range of <NUM> to <NUM> times a refractive index η1 of the first transparent resin.