JP2015166845A - Optical image forming element and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical image forming element in which high luminance ghost is hard to be generated.SOLUTION: An optical image forming element 1 is a plate-shaped optical image forming element in which one main surface constitutes a light incident surface 1a and the other main surface constitutes a light emission surface 1b. The optical image forming element 1 includes a plurality of quadrangular columnar translucent members 10 and a reflection film 20. The plurality of translucent members 10 are arranged in matrix along first and second directions. The plurality of translucent members 10 extend toward the light emission surface 1b side from the light incident surface 1a side. The reflection film 20 is arranged between translucent members 10 adjacent to each other.

Description

  The present invention relates to an optical imaging element and a manufacturing method thereof.

  Conventionally, an optical imaging element that forms an aerial image using scattered light emitted from the surface of an object is known. For example, Patent Document 1 discloses an optical imaging element having a first light control panel and a second light control panel. In this optical imaging element, the first light control panel and the second light control panel are constituted by transparent plates. Each of the first and second light control panels is provided with a plurality of plane reflecting portions extending perpendicular to the surface direction. Each of the plurality of planar reflection portions of the first and second light control panels extends along one direction, and is arranged along another direction perpendicular to the one direction. The first light control panel and the second light control panel are faced to each other so that the extending directions of the respective planar reflecting portions are orthogonal to each other.

JP 2012-14194 A

  The optical imaging element described in Patent Document 1 has a problem that a high-intensity ghost (undesired aerial image) is easily formed.

  A main object of the present invention is to provide an optical imaging element in which a high-intensity ghost hardly occurs.

  The optical imaging element according to the present invention is a flat optical imaging element in which one principal surface constitutes a light incident surface and the other principal surface constitutes a light emitting surface. An optical imaging element according to the present invention includes a plurality of light transmission members having a quadrangular prism shape and a reflective film. The plurality of translucent members are arranged in a matrix along the first and second directions. The plurality of translucent members extend from the light incident surface side toward the light emitting surface side. The reflective film is disposed between the adjacent translucent members.

  In the optical imaging element according to the present invention, it is preferable that the reflective film is formed on the translucent member.

  In the optical imaging element according to the present invention, the arithmetic average roughness (Ra) defined by JIS B0601-2001 on the side surface of the translucent member is preferably 0.1 nm or less.

  In the optical imaging element according to the present invention, the translucent member is preferably made of glass.

  The method for manufacturing an optical imaging element according to the present invention relates to a method for manufacturing the optical imaging element according to the present invention. In the method for manufacturing an optical imaging element according to the present invention, a reflection film forming step of forming a reflection film on at least two side surfaces of the light transmitting member is performed. The translucent member on which the reflective film is formed is aligned and fixed in a matrix.

  In the method of manufacturing an optical imaging element according to the present invention, the reflective film may be formed on two adjacent side surfaces of the light transmitting member in the reflective film forming step.

  In the method of manufacturing an optical imaging element according to the present invention, the reflective film may be formed on all four side surfaces of the light transmitting member in the reflective film forming step.

  According to the present invention, it is possible to provide an optical imaging element in which a high-intensity ghost hardly occurs.

It is a typical side view showing the use condition of the optical image formation element concerning a 1st embodiment. 1 is a schematic perspective view of an optical imaging element according to a first embodiment. 1 is a schematic cross-sectional view of an optical imaging element according to a first embodiment. FIG. 3 is a schematic exploded perspective view of a part of the optical imaging element according to the first embodiment. It is a typical sectional view of the optical image formation element concerning a reference example. 1 is a schematic cross-sectional view of an optical imaging element according to a first embodiment. FIG. 5 is a schematic exploded perspective view of a part of an optical imaging element according to a second embodiment. FIG. 10 is a schematic exploded perspective view of a part of an optical imaging element according to a third embodiment. It is a typical perspective view of the optical image formation element concerning a 4th embodiment. It is a typical side view for demonstrating the manufacturing process of the optical imaging element which concerns on 4th Embodiment. It is a typical perspective view for demonstrating the manufacturing process of the optical imaging element which concerns on 4th Embodiment.

  Hereinafter, an example of the preferable form which implemented this invention is demonstrated. However, the following embodiment is merely an example. The present invention is not limited to the following embodiments.

  Moreover, in each drawing referred in embodiment etc., the member which has a substantially the same function shall be referred with the same code | symbol. The drawings referred to in the embodiments and the like are schematically described. A ratio of dimensions of an object drawn in a drawing may be different from a ratio of dimensions of an actual object. The dimensional ratio of the object may be different between the drawings. The specific dimensional ratio of the object should be determined in consideration of the following description.

  FIG. 1 is a schematic side view showing a usage state of the optical imaging element according to the first embodiment of the present invention. An optical imaging element 1 shown in FIG. 1 is an element that images an object O that generates diverging light in a space. The optical imaging element 1 is usually arranged to be inclined with respect to the object O. The divergent light emitted from the object O is imaged in the space by the optical imaging element 1, and an image plane (aerial image) F is formed.

  FIG. 2 is a schematic perspective view of the optical imaging element according to the first embodiment. FIG. 3 is a schematic cross-sectional view of the optical imaging element according to the first embodiment. FIG. 4 is a schematic exploded perspective view of a part of the optical imaging element according to the first embodiment. As shown in FIGS. 1 to 3, the optical imaging element 1 has a flat plate shape. Specifically, the optical imaging element 1 has a rectangular plate shape. The optical imaging element 1 has a light incident surface 1a constituted by one main surface on the object O side and a light emitting surface 1b constituted by another main surface on the image plane F side.

  As shown in FIGS. 2 to 4, the optical imaging element 1 includes a plurality of translucent members 10. Each of the plurality of translucent members 10 has a quadrangular prism shape. More specifically, in this embodiment, each translucent member 10 is a quadrangular column (square column) having a square bottom surface.

  In the present invention, the “quadrangular column” includes one having a chamfered ridgeline portion or corner portion and one having a shape in which the ridgeline portion or corner portion is rounded.

  The material of the translucent member 10 is not particularly limited as long as it has visible light. The translucent member 10 can be made of, for example, glass, resin, ceramic, or the like.

  Each translucent member 10 includes a first end surface 10a, a second end surface 10b, a first side surface 10c, a second side surface 10d, a third side surface 10e, and a fourth side surface 10f. Have.

  The first end surface 10a constitutes the light incident surface 1a. The first end face 10a extends along the x-axis direction (first direction) and the y-axis direction (second direction). The x-axis direction and the y-axis direction are orthogonal to each other. The 2nd end surface 10b comprises the light-projection surface 1b. The second end face 10b also extends along the x-axis direction and the y-axis direction. Accordingly, the first end surface 10a and the second end surface 10b are parallel to each other, and the translucent member 10 extends from the light incident surface 1a side toward the light emitting surface 1b side.

  The first and second side surfaces 10c and 10d extend along the x-axis direction and the z-axis direction, respectively. The first side surface 10c and the second side surface 10d face each other in the y-axis direction. The z-axis direction is orthogonal to the x-axis direction and the y-axis direction.

  The third and fourth side surfaces 10e and 10f extend along the y-axis direction and the z-axis direction, respectively. The third side surface 10e and the fourth side surface 10f face each other in the x-axis direction.

  Ratio of the dimension (width) along the x-axis direction or the y-axis direction of the translucent member 10 with respect to the aspect ratio of the translucent member 10 (the dimension (height) along the z-axis direction of the translucent member 10) The height)) is preferably from 0.1 to 1, more preferably from 0.2 to 0.5.

  The plurality of translucent members 10 are arranged in a matrix along the x-axis direction that is the first direction and the y-axis direction that is the second direction.

  A reflective film 20 is provided between the light transmissive members 10 adjacent in the x-axis direction and between the light transmissive members 10 adjacent in the y-axis direction. The reflective film 20 is provided across the light incident surface 1 a and the light emitting surface 1 b of the optical imaging element 1. For this reason, the adjacent translucent members 10 are isolated by the reflective film 20. Light that enters the light transmissive member 10 and tries to go to the light transmissive member 10 adjacent to the light transmissive member 10 is reflected by the reflective film 20. For this reason, the light incident on the translucent member 10 does not substantially enter the translucent member 10 adjacent to the translucent member 10.

  In the present embodiment, the reflective film 20 is formed on the side surfaces 10 c to 10 f of the translucent member 10. More specifically, the reflective film 20 is formed on the first side surface 10c and the third side surface 10e of the translucent member 10. The second side surface 10d is covered with a reflective film 20 formed on the first side surface 10c of the translucent member 10 adjacent in the y-axis direction. The fourth side surface 10f is covered with a reflective film 20 formed on the third side surface 10e of the light transmissive member 10 adjacent in the x-axis direction.

  The material of the reflective film 20 is not particularly limited. The reflective film 20 is formed by alternately stacking a metal film made of a metal such as aluminum or silver, a high refractive index film having a relatively high refractive index, and a low refractive index film having a relatively low refractive index. It may be composed of a multilayer film or the like.

  An optical film such as an antireflection film or a wavelength selection film may be formed on each of the light incident surface 1a and the light emitting surface 1b of the optical imaging element 1.

  The manufacturing method of the optical imaging element 1 is not particularly limited. The optical imaging element 1 can be manufactured, for example, in the following manner.

  First, the reflective film 20 is formed on the first and third side surfaces 10c and 10e adjacent to each other of the translucent member 10 (reflective film forming step). The reflective film 20 can be formed by, for example, a sputtering method, a vacuum evaporation method, a chemical vapor deposition (CVD) method, or the like.

  Next, the optical imaging element 1 is completed by aligning and fixing the translucent member 10 having the reflective film 20 formed on the side surfaces 10c and 10e in a matrix along the x-axis direction and the y-axis direction. be able to.

  The method for fixing the plurality of translucent members 10 is not particularly limited. For example, a plurality of translucent members 10 may be fixed by providing an adhesive layer between adjacent translucent members 10. For example, you may fix the some translucent member 10 by inserting the some translucent member 10 in a frame.

  The divergent light emitted from each part of the object O enters the plurality of light transmissive members 10 constituting the optical imaging element 1 from the first end face 10a constituting the light incident face 1a. Of the incident light, the first or second side surface 10c, 10d extending along the x-axis direction and the z-axis direction once and the third or fourth side surface extending along the y-axis direction and the z-axis direction. The light (hereinafter referred to as “secondary reflected light”) emitted from the second end face 10b constituting the light emission surface 1b after being reflected twice in total, 10e and 10f, forms an image and forms an image plane. F is formed. Of the light incident from the light incident surface 1a, the light emitted from the light emitting surface 1b without being reflected by the side surfaces 10c to 10f, or the light emitted from the light emitting surface 1b after being reflected only once by the side surfaces 10c to 10f ( Hereinafter, “primary reflected light”) does not contribute to the formation of the image plane F. Of the light incident from the light incident surface 1a, an odd number of the light emitted from the light emitting surface 1b after being reflected by the side surfaces 10c to 10f at least three times (hereinafter referred to as “high-order reflected light”). The high-order reflected light that is reflected once does not contribute to the formation of the image plane F, and the higher-order reflected light that is reflected even times contributes to the formation of the image plane F, but is attenuated by absorption of the reflection film, and the luminance of the image. Will be reduced. At least a part of the high-order reflected light, the primary reflected light, and the directly emitted light that does not contribute to the formation of the image plane F is imaged at a position different from the image plane F. Thereby, a ghost is formed. The optical path length in the translucent member 10 of higher-order reflected light is relatively long. For this reason, a ghost formed by higher-order reflected light has a relatively low luminance. On the other hand, the optical path length in the translucent member 10 of primary reflected light is relatively short. For this reason, the ghost formed by the primary reflected light has a relatively high luminance. Therefore, from the viewpoint of suppressing the formation of a high-intensity ghost, it is important to suppress the primary reflected light from being emitted from the light emitting surface 1b.

  Here, as shown in FIG. 5, the first light control is arranged on the light incident surface 101 side, extends along the x-axis direction, and has a plurality of planar reflecting portions arranged along the y-axis direction. The panel 102 and the second light control panel 105 that is disposed on the light emitting surface 103 side, extends along the y-axis direction, and includes a plurality of planar reflecting portions 104 arranged along the x-axis direction. Assume an optical imaging element 100. In the optical imaging element 100, the first light control panel 102 does not have a planar reflection portion extending along the y-axis direction. For this reason, light from an object is likely to enter the second light control panel 105 without being reflected by the first light control panel 102. Therefore, the primary reflected light reflected only by the planar reflecting portion 104 is likely to be emitted from the light emitting surface 103. Therefore, a high-intensity ghost is easily formed by the primary reflected light.

  On the other hand, as shown in FIG. 6, in the optical imaging element 1 according to the present embodiment, each translucent member 10 is surrounded by a reflective film 20. For this reason, it is difficult for light to directly enter the portion of the reflective film 20 on the light emitting surface 1b side. A lot of incident light is reflected by the reflective film 20 at a portion on the light incident surface 1a side. Therefore, it is difficult for the primary reflected light to be emitted from the light emitting surface 1b. Therefore, formation of a high-intensity ghost due to the primary reflected light is effectively suppressed.

  Further, in the optical imaging element 1, the amount of secondary reflected light that contributes to the image formation on the image plane F tends to increase because the generation of the primary reflected light is suppressed. Therefore, the brightness of the image plane F can be increased. That is, a high-luminance aerial image can be formed.

  In the optical imaging element 100 shown in FIG. 5, the second light control panel 105 on the light emitting surface 103 side is not provided with a planar reflecting portion extending in the x-axis direction. For this reason, the light that is reflected by the planar reflection portion of the first light control panel 102 and then enters the second light control panel 105 and is reflected by the planar reflection portion 104 is not hindered from proceeding in the y-axis direction. . Therefore, the width of the light beam emitted from one segment of the optical imaging element 100 (the part corresponding to the part where the light transmitting member 10 of the optical imaging element 1 is provided) is wide.

  Further, in the optical imaging element 100, the first light control panel 102 on the light incident surface 101 side is not provided with a plane reflecting portion extending in the y-axis direction, and the second light on the light emitting surface 103 side. The control panel 105 is provided with a planar reflecting portion that extends in the y-axis direction. Therefore, the deviation between the light incident position and the light emitting position tends to be large.

  On the other hand, the optical imaging element 1 is provided so as to surround the translucent member 10 across the light incident surface 1a and the light emitting surface 1b. For this reason, both the progress of the secondary reflected light in the x-axis direction and the progress in the y-axis direction are likely to be hindered by the reflective film 20. Therefore, the light flux width of the secondary reflected light emitted from each translucent member 10 is narrow. Therefore, an image can be formed with high resolution.

  From the viewpoint of realizing higher resolution, the surface roughness of the side surfaces 10c to 10f is preferably 0.1 nm or less in terms of arithmetic average roughness (Ra) defined by JIS B0601-2001. This is because the side surfaces 10c to 10f are difficult to diffusely reflect and the straightness of the reflected light is easily maintained.

  Hereinafter, other examples of preferred embodiments of the present invention will be described. In the following description, members having substantially the same functions as those of the first embodiment are referred to by the same reference numerals, and description thereof is omitted.

  FIG. 7 is a schematic exploded perspective view of a part of the optical imaging element according to the second embodiment. FIG. 8 is a schematic exploded perspective view of a part of the optical imaging element according to the third embodiment.

  In the first embodiment, the example in which the reflective film 20 is formed on the first and third side surfaces 10c and 10e of the translucent member 10 has been described. However, the present invention is not limited to this. Further, for example, as in the optical imaging element shown in FIG. 7, the reflective film 20 may be provided on each of the first to fourth side surfaces 10 c to 10 f of the plurality of translucent members 10. For example, as in the optical imaging element shown in FIG. 8, the translucent member 10 having the reflective film 20 formed on the first and second side surfaces 10c and 10d, and the third and fourth side surfaces 10e and 10f. The translucent member 10 having the reflective film 20 formed thereon may be alternately provided along each of the x-axis direction and the y-axis direction.

(Fourth embodiment)
FIG. 9 is a schematic perspective view of the optical imaging element 2 according to the fourth embodiment. The optical imaging element 1 includes a frame 30 that surrounds a plurality of translucent members 10 arranged in a matrix. The frame 30 increases the rigidity of the optical imaging element 2.

  In the present embodiment, the frame body 30 has first to fourth frame body pieces 31 to 34. However, the present invention is not limited to this configuration. The frame body 30 may be provided integrally.

  The frame 30 can be made of, for example, glass, ceramics, plastic, or the like.

(Method for manufacturing optical imaging element 2)
FIG. 10 is a schematic side view for explaining a manufacturing process of the optical imaging element according to the fourth embodiment. FIG. 11 is a schematic perspective view for explaining a manufacturing process of the optical imaging element according to the fourth embodiment.

  The manufacturing method of the optical imaging element 1 is not specifically limited, For example, it can manufacture in the following ways.

  First, as shown in FIG. 10, the first plate 31a for constituting the first frame piece 31 and the second plate 32a for constituting the second frame piece 32 are fixed. To do. The fixing method is not particularly limited. For example, the first plate 31a and the second plate 32a may be fixed using an adhesive.

  Next, the translucent members 10 are arranged on the first and second plate bodies 31a and 32a. It is preferable to apply an adhesive to the translucent member 10 and adhere the translucent member 10 to the plates 31a and 32a and the translucent member 10 that has already been arranged.

  After arranging the translucent members 10, the third plate 33 a for constituting the third frame piece 33 and the fourth plate 34 a for constituting the fourth frame piece 34 are fixed. To do. The block 3 shown in FIG. 11 is manufactured by the above process.

  Next, the block 3 is cut along the cut line CL. Thereafter, the optical imaging element 1 can be completed by mirror-polishing the cut surface. The block 3 may be cut using, for example, a wire saw, a dicing saw, or laser cutting.

  According to the above manufacturing method, a plurality of optical imaging elements 1 can be manufactured with high manufacturing efficiency.

1: Optical imaging element 1a: Light incident surface 1b: Light exit surface 3: Block 10: Translucent member 10a: First end surface 10b: Second end surface 10c: First side surface 10d: Second side surface 10e: Third side surface 10f: Fourth side surface 20: Reflective film 30: Frame bodies 31 to 34: Frame body pieces

Claims (7)

A flat optical imaging element in which one principal surface constitutes a light incident surface and the other principal surface constitutes a light exit surface,
A plurality of rectangular columnar light-transmitting members arranged in a matrix along the first and second directions and extending from the light incident surface side toward the light emitting surface side;
A reflective film disposed between the light-transmissive members adjacent to each other;
An optical imaging element comprising:   The optical imaging element according to claim 1, wherein the reflective film is formed on the translucent member.   The optical imaging element of Claim 1 or 2 whose arithmetic mean roughness (Ra) prescribed | regulated by JISB0601-2001 of the side surface of the said translucent member is 0.1 nm or less.   The optical imaging element according to claim 1, wherein the translucent member is made of glass. A method for producing an optical imaging element according to any one of claims 1 to 4,
A reflective film forming step of forming the reflective film on at least two side surfaces of the translucent member; a step of aligning and fixing the translucent member formed with the reflective film in a matrix; and
A method for manufacturing an optical imaging element.   The method of manufacturing an optical imaging element according to claim 5, wherein in the reflection film forming step, the reflection film is formed on two adjacent side surfaces of the light transmitting member.   The method of manufacturing an optical imaging element according to claim 5, wherein, in the reflection film forming step, the reflection film is formed on all four side surfaces of the translucent member.