KR102211618B1 - A retroreflective micromirror array for a 3-dimensional floating image - Google Patents

Abstract

frame; A plurality of micro reflector structures arranged on one surface of the frame; And a protective layer formed on the surface of the reflector structure, wherein the micro reflector structure includes a first parabola formed from an arbitrary vertex extending in one direction and a second parabolic surface formed from the vertex extending in the other direction. It has a reflective surface made of a second parabolic surface, the first and second parabolic surfaces share the focal point of each parabolic surface, are mutually perpendicular at the vertices, and the refractive index of the protective layer is 1 or more. A micro mirror array is provided. The retroreflective micromirror array for a device for realizing a 3D floating image provided in one aspect of the present invention can be applied to various imaging equipment to provide improved image quality, and the reflector structure can be protected by a protective layer, and the light intensity can be reduced. There is an effect that it can be improved.

Description

A retroreflective micromirror array for a 3-dimensional floating image}

It relates to a retroreflective micromirror array for a device for realizing a 3D floating image.

Technology methods for realizing a three-dimensional (3D) image can be divided into a stereo-scopic display method and a 3D display method.

Among the stereo-scopic display methods, the glasses method has the disadvantage that glasses must be worn, the image is dark, and a special screen is required. In addition, the no-glasses method has a disadvantage in that the effective field of view is considerably narrow because it is necessary to observe from a predetermined position instead of wearing glasses.

On the other hand, the 3D display method, unlike the stereo-scopic method, does not require wearing glasses to check an image, so that practical observation is possible and has additional advantages. Among them, the volumetric display method represents a floating image in which an image is placed in the real world, not in virtual reality. Since these 3D floating images are real images floating in the air, they are observed directly and mutually It can be operated and has the advantage of being able to see the image from a very large angle.

On the other hand, with regard to the image enhancement device, Korean Patent Registration No. 10-0206689 (hereinafter abbreviated as'prior technology') is a flat plate in which the corner cubes are arranged, and the reflected light reflected from each corner cube reverses the direction of the incident light. A holographic screen having the property of returning to is disclosed. However, as in the prior art, in order to implement a volumetric display method, the array consisting of a corner cube reflector (CCR) consists only of a simple planar hexahedron, so the light reflected back for each CCR does not have a correct focus point. , There is a disadvantage that the virtual image is not clear and looks blurry.

Korean Patent Registration No. 10-0206689

An object of the present invention is to provide a micromirror array capable of protecting a reflective surface and improving the light intensity of a buoyant image by forming a protective layer having a different refractive index on a parabolic reflector structure.

In order to achieve the above object, in one aspect of the present invention

frame; A plurality of micro reflector structures arranged on one surface of the frame; And a protective layer formed on the surface of the reflector structure,

The micro-reflector structure has a reflective surface comprising a first parabolic surface in which a first parabolic formed from a vertex extends in one direction and a second parabolic surface in which a second parabolic formed from the vertex extends in the other direction,

The first and second parabolic surfaces share the focal point of each parabolic surface, and are mutually perpendicular at the vertices,

A retroreflective micromirror array for an apparatus for realizing a 3D floating image having a refractive index of the protective layer of 1 or more is provided.

The retroreflective micromirror array for a device for realizing a 3D floating image provided in one aspect of the present invention can be applied to various imaging equipment to provide improved image quality, and the reflector structure can be protected by a protective layer, and the light intensity can be reduced. There is an effect that it can be improved.

1 and 2 are schematic diagrams showing a retroreflective micromirror according to an embodiment of the present invention,
3 is a schematic diagram showing a retroreflective micromirror array according to an embodiment of the present invention,
4 is a schematic diagram showing a principle of implementation of a retroreflective micromirror array according to an embodiment of the present invention,
5 is a schematic diagram showing a parabolic retroreflective micromirror array in which curvatures are combined according to an embodiment of the present invention,
6 is a plan view and a side view showing a parabolic retroreflective micromirror array in which curvature is combined according to an embodiment of the present invention.
7 shows an image plotting result of a retroreflective micromirror array according to whether or not it is designed in consideration of the refractive index of a protective layer according to an embodiment of the present invention.
FIG. 8 is a schematic diagram showing whether light is condensed when two parabolas meet vertically and when not, according to an embodiment of the present invention,
9 is a schematic diagram showing a focal length calculation when a protective layer having a refractive index n is applied according to an embodiment of the present invention,
10 is a schematic diagram showing a process of retroreflection according to the presence or absence of a protective layer according to an embodiment and a comparative example of the present invention,
11 is a schematic diagram showing a design of a micro mirror array according to an embodiment of the present invention,
12 is a schematic diagram showing a parabolic design of a micromirror array according to an embodiment of the present invention,
13 shows simulation results comparing and showing the effect of improving light intensity according to the presence or absence of a protective layer according to an embodiment and a comparative example of the present invention.

Hereinafter, the present invention will be described in detail with reference to the contents described in the accompanying drawings. However, the present invention is not limited or limited by the exemplary embodiments. The same reference numerals shown in each drawing indicate members that perform substantially the same function.

Objects and effects of the present invention may be naturally understood or more apparent by the following description, and the objects and effects of the present invention are not limited only by the following description. In addition, in describing the present invention, when it is determined that a detailed description of a known technology related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

In one aspect of the present invention

frame; A plurality of micro reflector structures arranged on one surface of the frame; And a protective layer formed on the surface of the reflector structure,

The micro-reflector structure has a reflective surface comprising a first parabolic surface in which a first parabolic formed from a vertex extends in one direction and a second parabolic surface in which a second parabolic formed from the vertex extends in the other direction,

The first and second parabolic surfaces share the focal point of each parabolic surface, and are mutually perpendicular at the vertices,

A retroreflective micromirror array for an apparatus for realizing a 3D floating image having a refractive index of the protective layer of 1 or more is provided.

Hereinafter, a retroreflective micromirror array provided in an aspect of the present invention will be described in detail for each configuration.

First, the retroreflective micromirror array provided in one aspect of the present invention includes a frame and a plurality of micro reflector structures arranged on one surface of the frame.

A plurality of micro reflector structures may be arranged on one surface of the frame.

The micro reflector structure has a reflective surface comprising a first parabolic surface in which a first parabolic formed from a vertex extends in one direction and a second parabolic surface in which a second parabolic formed from a vertex extends in the other direction.

The first and second parabolic surfaces may extend to a length less than or equal to the frame.

The first and second parabolic surfaces may share an image focus. This can be seen in FIG. 2.

In an embodiment, light incident on the first parabolic surface may be focused to the image focus. Also, light incident on the second parabolic surface may be focused to the image focal point. In this way, in the reflective surface composed of two parabolic surfaces, each parabolic surface can share an image focus. That is, light incident on each parabolic surface included in the same reflective surface is retroreflected to form an image focal point at the same point, so that when a floating image is displayed, image quality may be improved.

The first and second parabolic surfaces are orthogonal to each other at a vertex. It can be seen that the cross sections of the reflective surfaces shown in FIGS. 1, 2, and 3 intersect different parabolic lines at the vertices. In other words, in the reflective surface including two different parabolic surfaces, the part in contact with the parabolic surface maintains a tangent line rather than a contact point, and the cross section of each parabolic surface at the corresponding tangent line confirms that the first and second parabola meet vertically at the vertex I can.

The basic property of a parabolic surface is that the light from the focal point is reflected as parallel light, or the incident collimated light is collected into the focus. However, even if the two parabolic planes share the focal point, if they do not face each other, the light does not return to the focal point, and the condition to return from the shared focal condition is that the two parabolas must face each other. This can be confirmed through FIG. 8. In this way, when the two parabolic lines face each other, the angle at the intersection is naturally perpendicular.

The frame may be provided in a flat or curved shape.

In addition, the frame may be provided in the shape of a cylindrical or elliptical cylindrical curved surface.

In addition, the frame is provided in a curved shape, and a distance from the center of the curved surface to the light source and a distance to a focal point at which the light source is retroreflected may be set equally.

In addition, a distance from the center of the curved surface to the light source and a distance to a focal point from which the light source is retroreflected may be set equal to the radius of curvature of the curved surface.

Next, the retroreflective micromirror array provided in one aspect of the present invention includes a protective layer formed on the surface of the reflector structure.

The refractive index of the protective layer may be 1 or more.

As the refractive index of the protective layer becomes 1 or more, it may be incident to the frame close to perpendicular, and in this case, the maximum light-receiving angle of light is improved, and thus the luminous intensity may be improved compared to the case without the protective layer.

That is, as can be seen through the left drawing of FIG. 10, when the protective layer is not formed, light incident close to the vertical can be reflected from the second reflective surface when incident on the edge of the RRMA, but the inclination angle has a certain limit. In the case of incident beyond, retroreflection does not occur.

On the other hand, when a protective layer material having a refractive index as shown in the right drawing of FIG. 10 is applied, the retroreflective angle and the range area are expanded within an appropriate range, which varies depending on the refractive index, but an efficiency improvement of about 5% to 15% is obtained. I can.

As the refractive index increases due to the application of the protective layer, the traveling direction of light may be changed according to Snell's law, and accordingly, the position of the focal point at which the light is collected may be changed.

For example, if the refractive index of the protective layer is n, when the parabola has a quasi-linear value of 2p', the focal point at which light is reflected back and gathered may be formed at a position of 2p'/n from the vertex.

The thickness of the protective layer is preferably a thickness that can sufficiently fill the gaps between the reflector parabolic surfaces, and if it is less filled, there is a problem that the effect of sufficiently protecting the reflector and improving light intensity cannot be sufficiently obtained.

When the thickness of the protective layer becomes thick, there is a problem that the transmittance of light may be lowered, and if the transparency of the protective layer is high, it is not a problem that the thickness becomes thick in terms of transmittance, but the material is wasted and the weight becomes heavy. There is a problem that it is inefficient in

The protective layer physically and chemically protects the reflector structure, thereby preventing damage to the reflector structure and improving the lifespan of the reflector structure.

The protective layer may be used without limitation as long as it is a transparent optical material, and for example, CR-39, acrylic, polycarbonate, or PS may be used as a material for a plastic lens.

Hereinafter, a design principle of a retroreflective micromirror array provided in an aspect of the present invention will be described in detail.

When the frame has a curved shape of a cylinder or an elliptical cylinder, if the radius of curvature of the curved surface is R, the parabolic may be designed using Equation 1 below.

<Equation 1>

d = 2p'/n = R

Here, d means'half the path of progress from the light source to the focus of the image', and in FIG. 4, it corresponds to the distance from the center of the curved surface to the light source.

Also, 2p' corresponds to the quasi-linear value of the designed parabola.

That is, the value obtained by dividing the quasi-linear value of the designed parabola by n should be designed to coincide with d and R.

To explain this in detail, the traveling direction and distance for recondensing of the return light in the vertical direction is based on the distance from the center of the curved surface of the reflector to the light source, and this must be accurately matched with the return in the left and right directions.

Re-condensing in the vertical direction is a principle of collecting light from a light source at a different focus by using the property of an ellipse (double focus). It can be applied by approximating it with the cylindrical curvature R.

At this time, in order to optimally design the moving distance of the light beam between the bifocals, the condition of d = R must be satisfied.

In addition, as described above, recondensing in the left and right directions is a principle of collecting light at a preset focal length using the property of a parabolic in which light from the focus is reflected as parallel light or the incident parallel light is focused. .

Therefore, since the regression in the vertical direction should be consistent with the recursion in the left and right directions, the focal length according to the recondensation in the left and right direction and d and R set according to the recondensation in the vertical direction must match.

However, as can be seen in FIG. 9, as the refractive index increases due to the application of the protective layer, the light traveling direction is changed according to Snell's law, and the parabolic value of the parabolic surface to be designed is changed accordingly. do.

If you set the parabolic parabola's parabolic value to 2p' = 2np, if there is no protective layer (i.e., the refractive index is 1), the focus of light will be at a distance of 2np, but when a protective layer with a refractive index of n is applied, the path As it changes, the focus is located at the position of 2p. That is, in consideration of the refractive index n, the parabolic surface should be designed to have a parabolic parabolic value that is n times the set focal length.For example, to form a focal point at the position of 2p, the parabolic parabolic value 2p' = 2np The parabolic surface should be designed.

Therefore, as shown in Equation 1, d = R = focal length must be satisfied, and if the parabolic parabolic value is 2p', the focal length is 2p'/n, so d = R = 2p'/n must be satisfied.

That is, a 3D floating image with improved image quality and luminosity by designing a parabola in consideration of the refractive index n of the protective layer to consider the regression in the left and right directions, and setting the curved surface of the frame to match the regression in the vertical direction. Can be obtained.

<Example 1> Preparation 1 of retroreflective micromirror array

A plurality of micro reflector structures arranged on one surface of the curved frame was formed, and a protective layer was formed on the surface of the reflector structure.

The distance from the center of the reflector to the light source was set to d = 200 mm, which was set equal to the curvature R of the curved surface.

The micro reflector structure includes two parabolic surfaces that share a focal point and are perpendicular to each other at one vertex, and the refractive index n of the protective layer is set to 1.3, which is a value greater than 1, and the focal length is set to 2p = 200 mm, and then the protective layer Considering the parabolic line, the parabola was designed by applying 2p' = 260 mm.

That is, it was designed to satisfy d = 2p'/n = R. This can be understood through FIGS. 11 and 12.

<Example 2> Preparation 1 of retroreflective micromirror array

A retroreflective micromirror array was manufactured in the same manner as in Example 1, but the parabolic was not designed in consideration of the protective layer, and the parabolic was designed by setting the parabola to a value equal to the focal length 2p = 200 mm.

<Comparative Example 1> Preparation of retroreflective micromirror array without protective layer

In the same manner as in Example 2, the parabola was designed by setting the parabola to a value equal to the focal length 2p = 200 mm, but no protective layer was formed.

<Experimental Example 1>

Fig. 7 shows the image plotting results of the retroreflective micromirror arrays for Examples 1 and 2.

As can be seen in FIG. 7, when designing the retroreflective micromirror array in consideration of the refractive index n of the protective layer, it can be seen that image quality is remarkably improved.

<Experimental Example 2>

For Example 1 and Comparative Example 1, the number (number of samples) of incident rays on the receiving surface formed at the formation focus was confirmed as a simulation result, and is shown in FIG. 13.

As can be seen in FIG. 13, when the protective layer is present, the number of samples is increased by 3,000 or more compared to the case without the protective layer, and thus it can be seen that the luminous intensity is improved.

Claims (7)

frame; A plurality of micro reflector structures arranged on one surface of the frame; And a protective layer formed on the surface of the reflector structure,
The micro reflector structure has a reflective surface comprising a first parabolic surface in which a first parabola formed from an arbitrary vertex extends in one direction and a second parabolic surface in which a second parabola formed from the vertex extends in another direction,
The first and second parabolic surfaces share the focal point of each parabolic surface and are mutually perpendicular at the vertex,
The refractive index of the protective layer is 1 or more,
The frame is provided in a curved shape, and the distance from the center of the curved surface to the light source and the distance from the center of the curved surface to the focal point at which the light source is retroreflected are the same,
The distance from the center of the curved surface to the light source and the distance from the center of the curved surface to the focal point at which the light source is retroreflected are the same as the radius of curvature of the curved surface,
Retroreflective micromirror array for 3D floating image realization device
The method of claim 1,
When the quasi-linear value of the first and second parabola is 2p', and the refractive index of the protective layer is n,
A retro-reflective micromirror array for a device for realizing a three-dimensional floating image, characterized in that a focal point is formed by retro-reflecting light at a position of 2p'/n from the vertex.
delete delete The method of claim 1,
The curved surface is a retro-reflective micromirror array for a three-dimensional floating image realization apparatus, characterized in that the curved surface shape of a cylinder or an elliptical column.
delete The method of claim 1,
The retroreflective micromirror array for the device for realizing a 3D floating image satisfies Equation 1 below.
<Equation 1>
R = 2p'/n = d
(The R is the radius of curvature of the curved surface,
2p' is a semilinear value of the first and second parabolics,
N is the refractive index of the protective layer,
D is a distance from the center of the curved surface to the light source or a distance from the center of the curved surface to a focal point at which the light source is retroreflected).

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