JP3341342B2 - Diffraction grating array and stereoscopic image display using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diffraction grating array for displaying a three-dimensional image and a three-dimensional image display device using the same.
In particular, a diffraction grating array capable of easily displaying a stereoscopic image having parallax only in the horizontal direction or having parallax in both the horizontal direction and the vertical direction, easily being optically produced, and being inexpensive for mass production. The present invention relates to a three-dimensional image display device using the same.

[0002]

2. Description of the Related Art Conventionally, a display having a diffraction grating pattern formed by arranging a plurality of minute dots made of a diffraction grating on the surface of a flat substrate has been widely used. As a method for producing a display having this kind of diffraction grating pattern, there is a method disclosed in, for example, Japanese Patent Application Laid-Open No. 60-156004. In this method, minute interference fringes (hereinafter referred to as diffraction gratings) due to two-beam interference are sequentially exposed on a photosensitive film while changing the pitch, direction, and light intensity.

On the other hand, recently, an XY stage on which a planar substrate is mounted is moved by using, for example, an electron beam exposure apparatus and under computer control, so that a plurality of minute The present inventor has proposed a method of manufacturing a display on which a diffraction grating pattern having a certain pattern is formed by arranging various dots. The method is described in “US Patent Application Serial No. 276,4, filed November 25, 1988.
No. 69 ".

[0004]

However, in a display manufactured by such a manufacturing method, an image input by an image scanner or the like or a computer graphic is used as a picture of a display having a diffraction grating pattern. A two-dimensional image is used. For this reason, since the pattern represented by the diffraction grating pattern is located on a plane on the substrate on which the diffraction grating is arranged, it is planar (two-dimensional).
3D (three-dimensional) that can express only natural patterns
There is a problem that it is not possible to express a simple pattern.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can easily display a stereoscopic image having parallax only in the horizontal direction or having parallax in both the horizontal and vertical directions. It is an object of the present invention to provide a diffraction grating array which is optically easy to manufacture, is inexpensive and can be mass-produced, and a three-dimensional image display device using the same.

[0006]

In order to attain the above object, first, a diffraction grating array according to the first aspect of the present invention has a structure in which the thickness of the diffraction grating is gradually reduced inside the cell and the spacing is gradually reduced. A diffraction grating that narrows is formed, and a plurality of diffraction grating cells having a function of diverging or condensing light are arranged on a flat substrate, and the diffraction grating cells are spatially arranged in a region where the grating gradient is close. In the horizontal direction, each divided area is made to correspond to a pixel of each parallax image (one direction).

[0007] A three-dimensional image display device according to a third aspect of the present invention is a device for displaying a three-dimensional image.
Is provided as a basic device to display a stereoscopic image having parallax only in the horizontal direction.

On the other hand, in the diffraction grating array according to the present invention, a diffraction grating in which the thickness of the diffraction grating is gradually reduced and the interval is gradually reduced is formed inside the cell, and light is diverged. Alternatively, a plurality of diffraction grating cells having a function of condensing light are arranged on a planar substrate, and the diffraction grating cells are spatially divided in a horizontal direction and a vertical direction in a region where a gradient of the grating and a grating interval are close to each other. Each divided area is divided into each parallax image (2
Direction) pixels.

According to a thirteenth aspect of the present invention, there is provided a three-dimensional image display apparatus for displaying a three-dimensional image, comprising the diffraction grating array according to the eleventh aspect as a basic device, and having a parallax in both the horizontal and vertical directions. Is displayed.

Here, in particular, a Fresnel zone plate having an off-axis imaging function is used as the diffraction grating.

In each divided region of the diffraction grating cell, only the diffraction grating having an area proportional to the brightness of the corresponding pixel of the corresponding parallax image is formed on the substrate.

Further, in each of the divided regions of the diffraction grating cell, a light-shielding layer or a light-transmitting layer is provided on the substrate surface so that light is transmitted only in an area proportional to the brightness of the corresponding pixel of the corresponding parallax image. ing.

On the other hand, a three-dimensional image can be displayed by controlling the intensity of light incident or emitted at a position corresponding to each divided region of the diffraction grating cell by a spatial light modulator.

Further, a full-color image can be displayed by selecting a wavelength of light at a position corresponding to each divided region of the diffraction grating cell by an optical frequency filter.

That is, the above-mentioned lattice spacing is calculated by the following equation, and three diffraction grating cells having lattice spacings corresponding to the respective colors of R, G and B are set as one set, and the R of the corresponding pixel of the corresponding parallax image is set. Based on the value of, the intensity of the light incident or emitted at the position corresponding to each divided region of the cell for R is controlled by the spatial light modulator, the wavelength of the light of R is selected by the optical frequency filter, and By performing the same operation for each color of R, G, and B and all pixels of all parallax images, a full-color stereoscopic image can be displayed. _{λ = d x (sinβ x -sinθ} x) λ = d y (sinβ y -sinθ y) (λ: wavelength of light, d _x: X component of the lattice spacing, d _y: Y component of the lattice spacing, theta _x: Incident angle in XZ plane, θ _y : Y
-Angle of incidence in the Z plane, β _x : diffraction angle in the XZ plane, β
_y : diffraction angle in the YZ plane) In each of the divided regions of the diffraction grating cell, an area proportional to the brightness of the corresponding pixel of the corresponding parallax image is set as a transmission portion by the spatial light modulator. I have to.

Further, in each of the divided regions of the diffraction grating cell, a transmissivity proportional to the brightness of the corresponding pixel of the corresponding parallax image is realized by the spatial light modulator.

[0017]

Therefore, in the diffraction grating array according to the first and third aspects of the present invention and the three-dimensional image display apparatus using the same, a three-dimensional image having parallax in the horizontal direction is observed in a wide viewing area in the vertical direction. can do.

In this case, by using a diffraction grating having a function of diverging or condensing light, it is possible to arbitrarily divide the viewing area and to give a smooth three-dimensional effect when the viewpoint moves.

Further, in the diffraction grating array and the stereoscopic image display device using the same according to the present invention, a stereoscopic image having parallax in both the horizontal and vertical directions can be displayed in the vertical and horizontal directions. Can be observed in a wide viewing area.

In this case, by using a diffraction grating having a function of diverging or condensing light, it is possible to arbitrarily divide the viewing area and to give a smooth three-dimensional effect when the viewpoint is moved.

On the other hand, a three-dimensional moving image can be displayed by controlling the intensity of light incident or emitted at a position corresponding to each divided region of the diffraction grating cell by a spatial light modulator.

Further, the intensity of the light incident or emitted at the position corresponding to each divided region of the diffraction grating cell is controlled by a spatial light modulator, and the wavelength of the light at the position corresponding to each divided region of the diffraction grating cell is converted to light. By selecting with a frequency filter, a monochromatic three-dimensional moving image can be displayed.

In each divided region of the diffraction grating cell, a light-shielding layer or a transparent layer is formed on the substrate surface by a method such as printing so that light is transmitted only through an area proportional to the brightness of the corresponding pixel of the corresponding parallax image. By providing the optical layer, a device for displaying a stereoscopic image in a very short time, at low cost, and easily can be manufactured.

On the other hand, a full-color stereoscopic image can be observed by selecting a wavelength of light at a position corresponding to each divided region of the diffraction grating cell by an optical frequency filter.

In each of the divided regions of the diffraction grating cell, the area proportional to the brightness of the corresponding pixel of the corresponding parallax image is set as a transmitting portion by the spatial light modulator, so that the spatial light modulator can transmit light. A three-dimensional image can be displayed even with a binary control device of / blocking.

Further, in each divided area of the diffraction grating cell, the spatial light modulation element realizes a transmittance proportional to the brightness of the corresponding pixel of the corresponding parallax image, so that the spatial light modulation element can With the resolution of the size of the divided area, display of a stereoscopic image with gradation can be realized.

Further, since a surface relief type diffraction grating can be used as the diffraction grating, mass production can be performed by inexpensive and simple production by a method such as embossing.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention is that a diffraction grating is formed in a cell such that the thickness of the diffraction grating is gradually narrower and the interval is gradually narrowed, and the diffraction grating has a function of diverging or condensing light. A plurality of grating cells are arranged on a planar substrate, and the diffraction grating cell is divided spatially in a region where the gradient of the grating or the gradient of the grating and the spacing between the gratings are close, in the horizontal direction, or in the horizontal and vertical directions. Then, a diffraction grating array in which each of the divided regions is made to correspond to each parallax image (one direction or two directions) is obtained, and this diffraction grating array is used as a basic device, and only in the horizontal direction or in both the horizontal and vertical directions. Another object of the present invention is to provide a three-dimensional image display device capable of displaying a three-dimensional image having parallax.

In such a three-dimensional image display device, full-color display is relatively easy, and a three-dimensional moving image can be displayed in combination with a spatial light modulator such as a liquid crystal display.

On the other hand, when a three-dimensional image display device having parallax only in the horizontal direction is manufactured using this diffraction grating array, there is an effect that the visual field is widened in the vertical direction.

When a three-dimensional image display device having parallax in both the horizontal and vertical directions is manufactured using this diffraction grating array, there is an effect that the visual field is widened in the vertical and horizontal directions.

Hereinafter, an embodiment of the present invention based on the above concept will be described in detail with reference to the drawings.

One example of the diffraction grating array according to the present invention is shown in FIG.
(A)], a cell 1 composed of a diffraction grating having a function of condensing light (in which a diffraction grating pattern in which the thickness of the diffraction grating is gradually reduced and the interval is gradually reduced) is described. As shown in FIG. 2, a plurality of diffraction grating cells 1 are arranged on a planar substrate 2, and the diffraction grating cell 1 is spatially divided horizontally in a region where the grating gradient is close, as shown in FIG.
Each of the divided regions is made to correspond to each parallax image (one direction), or the diffraction grating cell 1 is spatially and horizontally oriented in a region where the gradient of the grating and the grating interval are close as shown in FIG. And each of the divided areas is made to correspond to each parallax image (two directions).

In FIG. 2, for convenience of illustration, FIG.
The pattern of the diffraction grating cell 1 in (b) is drawn upside down and the thickness of the diffraction grating is drawn to be almost equal, and the corresponding portions in each of the subsequent drawings will be drawn in the same manner.

In other words, in this case, the number of divided regions of the diffraction grating cell 1 is equal to the number of parallax images, and any pixel of any parallax image corresponds to that parallax image in the cell at the same position of the diffraction grating array. Corresponds to the area assigned to Here, the parallax image when viewed from the left corresponds to the right divided region of the diffraction grating cell 1, and the parallax image when viewed from the center corresponds to the central divided region of the diffraction grating cell 1. I have.

Similarly, when the region is divided also in the vertical direction, the parallax image when viewed from above corresponds to the divided region below the diffraction grating cell 1 and when viewed from below. The parallax image corresponds to the divided area on the diffraction grating cell 1.

Further, the brightness of each pixel of the parallax image is proportional to the area of the diffraction grating in the corresponding divided area or the transmission area or light transmittance of the spatial light modulator corresponding to the area.

Next, a more detailed configuration of the diffraction grating cell 1 and diffraction in a minute area thereof will be described with reference to FIGS.

FIG. 5 shows the case of incident light having an optical axis parallel to the YZ plane. In this case, the diffraction angles β _x and β _y of the + 1st-order diffracted light in the figure follow the following equation.

[0040] _{λ = d x (sinβ x)} ...... (1) λ = d y (sinβ y -sinθ y) ...... (2) where, lambda is the wavelength of light, d _x, d _y is X grid interval component,
Y component, θ _x , θ _y are incident angles in XZ plane and YZ plane, β _x is diffraction angle in XZ plane, β _y is diffraction angle in YZ plane Is shown. Note that the gradient of the diffraction grating in the XY plane is Ω = tan ⁻¹ (d _y / d _x ).

From these equations, it can be seen in which direction the diffraction grating in an arbitrary minute region emits light. Therefore, in all the diffraction grating cells 1, an image is expressed using a diffraction grating region provided with a condition to be observed from a certain observation position (control of the intensity of light incident on the region, or the intensity of the emitted diffracted light). Control), the image can be observed only from the observation position. Then, if this is performed for all observation positions, that is, processing is performed for all regions in the diffraction grating cell 1, each parallax image can be displayed in each direction. Therefore, observation of a stereoscopic image by binocular parallax can be performed. It becomes possible.

On the other hand, the diffraction grating cell 1 can be manufactured by a two-beam interference method using an optical system as shown in FIG. 6, for example. The diffraction grating array 2 of the present embodiment can be obtained by changing the position in the above.

That is, as shown in FIG. 6, a laser beam generated from a laser light source and reflected by a mirror is split into two by a half mirror, one of which is incident on the photosensitive material as parallel light through a lens system. At the same position on the photosensitive material, the other laser beam is incident as focused light through another lens system. Thereby, in the photosensitive material,
Interference fringes due to the two lights are recorded. By performing such an operation while changing the position of the photosensitive material, a diffraction grating array having interference fringes recorded on the entire surface is obtained. In addition,
If the diffraction grating array is a surface relief type, duplication by embossing can be easily performed.

In this case, the optimum focusing position for each diffraction grating cell 1 is calculated from the observation conditions, and based on this, each diffraction grating cell 1 is manufactured while the optical system is changed little by little. As a result, the most desirable diffraction grating array 2 is obtained.

Further, when the parallax is provided only in one direction, a cylindrical lens may be used as the lens that forms the focused light immediately before the photosensitive material.

However, the present invention is not limited to this. The diffraction grating cell 1 is manufactured by calculating a grating having the same function as the above-described diffraction grating and drawing the image with an apparatus having a fine processing capability such as an electron beam drawing apparatus. Is also possible.

As described above, in the diffraction grating array 2 of this embodiment, it is possible to realize a device that spreads and diffracts light in a predetermined area in the vertical and horizontal directions.

That is, in the case of the diffraction grating array 2 composed of the diffraction grating cells 1 as shown in FIG.
By changing the components, light that spreads and diffracts in the horizontal direction is divided into fields of view in the horizontal direction by dividing the diffraction grating in the horizontal direction, and different parallax images are reproduced in each of the divided fields of view. Since light is spread and diffracted in the vertical direction due to the change in the Y component of the interval, a stereoscopic image having parallax only in the horizontal direction can be observed in a wide viewing area in the vertical direction.

In the case of the diffraction grating array 2 composed of the diffraction grating cells 1 as shown in FIG. 4, the light that spreads and diffracts in the vertical direction due to the change in the Y component of the grating interval is transmitted in the vertical direction of the diffraction grating. The field of view is divided vertically by area division,
Since different parallax images are reproduced in each of the divided visual fields, a stereoscopic image having parallax in both the horizontal and vertical directions can be observed.

This is because each of the gratings forming each diffraction grating cell 1 has a function of condensing light. That is, since each diffraction grating has a function of condensing light, considering a minute region in the cell, diffracted light from the minute region is emitted in a specific direction. Focusing on different minute regions in the cell, the diffracted light is emitted in different specific directions. In other words, a diffraction grating having a function of condensing light can be considered as a continuous aggregate of minute diffraction gratings that emit light in different directions.

This diffraction grating is divided into an arbitrary number of minute regions having a certain size, and X-
Considering an observation plane parallel to the Y plane, the diffracted light from each minute area has a certain spread. However, on the observation surface, the diffracted lights in each minute area are continuous with each other but do not overlap.

Accordingly, the diffraction grating array 2 in which the diffraction grating cells 1 are arranged as described above converts a parallax image obtained from the same parallax direction as the parallax direction on the observation surface into a diffraction grating which emits diffracted light in the corresponding parallax direction. By displaying the area as a pixel and displaying the same number as the number of divided areas to be diffracted, it becomes possible to observe a stereoscopic image having a natural stereoscopic effect on the observation surface. Also, in this case, when the observer moves the viewpoint up, down, left, and right in the observation plane, the stereoscopic image changes smoothly, and a natural viewpoint movement is obtained. Even when the viewpoint is moved before and after the observation plane, a natural three-dimensional effect can be obtained with considerable freedom. Furthermore, when the observer deviates from the observable area (viewing area), nothing is observed by the observer, and the observer can easily recognize the observable area (for example, in a stereoscopic image display using a lenticular lens, When the user deviates from the set observation area, the stereoscopic effect of the image is inverted, and it is difficult for the observer to recognize the boundary.

As described above, in the diffraction grating array 2 of this embodiment, a stereoscopic image having parallax only in the horizontal direction or having parallax in both the horizontal and vertical directions can be displayed with a natural stereoscopic effect. .

On the other hand, since the above-described diffraction grating array 2 can be a surface relief type diffraction grating, mass production can be performed at low cost by the embossing method. For this reason, by using this as a basic device, various types of stereoscopic image display devices (for example, a display, a stereoscopic television, a stereoscopic hard copy, etc.) can be realized in large quantities at a relatively low cost.

That is, for example, for a high-resolution television,
A three-dimensional television can be realized by combining the diffraction grating array of the present embodiment with the configuration of the present embodiment, and a three-dimensional hard copy can be realized by using the diffraction grating array of the present embodiment, which is embossed and duplicated, instead of paper of a high-resolution printer. Can be.

Hereinafter, an application example of the diffraction grating array of this embodiment will be specifically described.

(A) FIG. 7 shows an example of the configuration of a display which is a three-dimensional image display device using the diffraction grating array of the present embodiment. FIG. 7 (a) is an exploded perspective view thereof, and FIG. )
Shows enlarged cross-sectional views of main components.

That is, as shown in FIG. 7, the display of this embodiment has the above-mentioned diffraction grating array 11 composed of a resin layer (diffraction grating forming layer) 11A and a reflective layer (Al deposited layer) 11B on the surface thereof. A color filter layer 12 which is an optical frequency filter provided on the front surface of the diffraction grating array 11, and a light shielding layer (printing layer) 13 provided on the front surface of the color filter layer 12.

In the display of this embodiment,
Considering a minute area, transmission / shielding of white incident light is selected by the light shielding layer 13, a certain wavelength is selected from the incident light by the color filter layer 12, and reaches the diffraction grating array 11. Light is diffracted with high efficiency by the reflective layer 11B formed on the surface of the diffraction grating array 11. At this time, in the emission direction of the diffracted light, the diffraction angle β _{x in the} X direction is determined by the X component of the lattice interval of the minute region, and the diffraction angle β _{y in the} Y direction is determined by the Y component of the lattice interval. Then, when observed from the direction of the diffraction angle, as described with reference to FIGS. 2 and 5, the minute region appears to shine.

In FIG. 7, the arrangement of the light-shielding layer 13 and the color filter layer 12 may be reversed from that shown in the figure. Although FIG. 7 includes the light shielding layer 13, the same effect can be obtained by destroying the diffraction grating in the corresponding part instead of providing the light shielding layer.

(B) FIG. 8 shows an example of the configuration of a stereoscopic television which is a stereoscopic image display device using the diffraction grating array of the present embodiment. FIG. 8 (a) is an exploded perspective view thereof, and FIG. b) is an enlarged cross-sectional view of the main component.

That is, as shown in FIG. 8, the stereoscopic television of this embodiment includes the above-described diffraction grating array 21, a liquid crystal display element 22 which is a spatial light modulator provided on the rear surface of the diffraction grating array 21, and And a color filter layer 23 provided on the rear surface of the liquid crystal display element 22.

In the three-dimensional television of this embodiment, considering a minute area, a certain wavelength is selected from the incident light by the color filter layer 23 for the white incident light, and the light is transmitted by the liquid crystal display element 22. With the selection of “/ block”, the transmitted light reaches the diffraction grating array 21.
Here, the diffraction grating array 21 is formed of a light transmissive resin plate or the like, and the arrived light is diffracted when transmitted. At this time, in the emission direction of the diffracted light, the diffraction angle β _{x in the} X direction is determined by the X component of the lattice interval of the minute region, and the diffraction angle β _{y in the} Y direction is determined by the Y component of the lattice interval. Then, when observed from the direction of the diffraction angle, as shown in FIGS. 2 and 5, the minute region appears to shine at the selected wavelength.

In FIG. 8, the arrangement order of the color filter layer 23, the liquid crystal display element 22, and the diffraction grating array 21 may be changed.

Next, regarding the correspondence with the original subject,
This will be described with reference to FIGS.

In FIG. 9, the upper part of the drawing shows the state of photographing the subject 24 having a parallax in the vertical direction. Here, nine parallax images of the three-dimensional subject 24 are obtained by the arrangement of the 3 × 3 cameras 25.

The lower left part of the figure shows an example of the obtained parallax image. Now, considering a pixel indicated by a black square of the same coordinates of each parallax image, it corresponds to each divided region of the diffraction grating cell at the same coordinate position of the stereoscopic television of the present embodiment at the lower right of the drawing. .
At this time, the brightness of the pixel corresponding to the black square of each parallax image is proportional to the transmittance in the region on the spatial light modulator (the liquid crystal display device 22) corresponding to each divided region of the diffraction grating cell. Control the light modulation element. When such an operation is performed for all pixels, and monochromatic light is incident from a predetermined position, a stereoscopic image can be observed.

Here, in the case of full color, FIG.
As shown in (1), the brightness of the pixel in the above operation is defined as the value of R of the pixel, and a filter that transmits only light of R color is arranged in accordance with the diffraction grating cell. This operation may be repeated for the remaining G and B.

(C) FIG. 11 is a schematic view showing an example of producing a three-dimensional hard copy which is a three-dimensional image display device using the diffraction grating array of this embodiment.

That is, as a method of producing a three-dimensional hard copy, as shown in FIG.
Based on the above, the pattern of the light-shielding layer is calculated by the computer 32, and the pattern of the light-shielding layer is output to the printer 33, which is a peripheral device of the computer 32, thereby forming the light-shielding layer on the mass-produced diffraction grating array 34. With this arrangement, a hard copy 35 of a stereoscopic image can be obtained.

The three-dimensional hard copy produced in this manner is shown in FIG. 12 (FIG. 12 (a) is an exploded perspective view thereof, and FIG. 12 (b) is an enlarged cross-sectional view of a main component. The three-dimensional hard copy according to the present embodiment includes a resin layer (diffraction grating forming layer) 41A and a reflective layer (Al
The above-mentioned diffraction grating array 41 composed of 41B)
And a protective layer 42 provided on the front surface of the diffraction grating array 41.
And a light shielding layer (printing layer) 4 provided on the front surface of the protective layer 42.
3.

In the three-dimensional hard copy of the present embodiment, when considering a minute area, transmission / blocking of white incident light is selected by the light shielding layer 43 and reaches the diffraction grating array 41 through the protective layer 42. Then, light is diffracted with high efficiency by the reflective layer 41B formed on the surface of the diffraction grating array 41. At this time, in the emission direction of the diffracted light, the diffraction angle β _{x in the} X direction is determined by the X component of the lattice interval of the minute region, and the diffraction angle β _{y in the} Y direction is determined by the Y component of the lattice interval. Then, when observed from the direction of the diffraction angle, as described with reference to FIGS. 2 and 5, the minute region appears to shine.

As described above, by forming only the light shielding layer 43 each time, a three-dimensional hard copy can be obtained in an extremely short time.

As described above, the following effects can be obtained in the three-dimensional image display device of each of the embodiments (a) to (c).

(A) From the viewpoint of a three-dimensional moving image display element First, using a pair of polarizing glasses and liquid crystal shutter glasses,
An eye-based method (two parallax images are used, and each parallax image is distributed to the left and right eyes to enable observation of a stereoscopic image) is general. However, these methods require the observer to wear special glasses and the like, and are of the twin-lens type.
There is no change in the image when changing the specific viewpoint when viewing a three-dimensional object.

Other techniques for displaying a three-dimensional moving image include "multiplex hologram" and "combination of lenticular plate and TV". But,
The former is a repetition of a predetermined image, and the latter has a drawback that the stereoscopic effect is reversed when the position of the viewpoint changes. Further, in both cases, even though they are stereoscopic images, they are only parallaxes in the horizontal direction.

On the other hand, the three-dimensional image display device of the present embodiment does not require the observer to attach a special instrument, and enables observation of the three-dimensional image in a relatively wide field of view. Also, if the image deviates slightly from the predetermined viewing area, the image becomes invisible and the stereoscopic effect does not reverse, so that the observer can easily recognize the viewing area, and thus is extremely easy to see. Furthermore, in addition to the parallax in the horizontal direction, there is also a parallax in the vertical direction. Furthermore, by combining optical frequency filters for R, G, and B wavelengths (for example, a color filter of a television) and arranging the diffraction grating cells 1 in accordance with the constituent units of each optical frequency filter, a full-color image is obtained. It is possible to display a three-dimensional moving image.

(B) From the viewpoint of three-dimensional hard copy One of the conventional methods for obtaining a three-dimensional hard copy is, for example, a 3D printer. However, since it is necessary to perform imaging similar to a Lippmann hologram for each point on the hologram, it takes time in proportion to the number of pixels, and further requires development processing before imaging.

On the other hand, in the three-dimensional image display device of this embodiment, it is not necessary to use special light such as laser light,
If the accuracy of a computer printer, plotter, etc. is sufficient, it is only necessary to output the part that becomes the light-shielding part, and it is possible to obtain a hard copy of a three-dimensional image in a very short time as if printing on paper. Become. this is,
The present invention can be applied to a copying machine and a printing machine, that is, a three-dimensional image copying machine and three-dimensional printing can be realized.

More specifically, the following various effects can be obtained.

(A) Light is condensed in the vertical direction by a diffraction grating having a function of condensing light, and then spread and diffracted.
A stereoscopic image having a parallax in the horizontal direction can be observed in a wide viewing range in the vertical direction.

In this case, since a diffraction grating having a function of condensing light is used, the viewing area can be arbitrarily divided, and a smooth three-dimensional effect can be felt when the viewpoint moves.

(B) After condensing the light in the vertical direction by a diffraction grating having a function of condensing light, the field of view is divided in the vertical direction by dividing the light that spreads and diffracts into vertical regions by dividing the diffraction grating into vertical regions.
Since different parallax images are reproduced in each of the divided visual fields, a stereoscopic image having parallax in both the horizontal and vertical directions can be observed.

(C) The diffraction grating array of this embodiment in which diffraction grating cells are formed on the entire surface is prepared, and the direction of the diffracted light is controlled by destroying the diffraction grating in an unnecessary area by heat or pressure. Therefore, when the diffraction grating is partially destroyed by a method such as heating or pressing, a three-dimensional image display device that displays a three-dimensional image easily and in a very short time can be manufactured.

(D) The diffraction grating array of this embodiment in which the diffraction grating cells are formed on the entire surface is prepared, and a light shielding layer is formed on the surface of the diffraction grating in an unnecessary area by a method such as printing. Since the direction of the diffracted light can be controlled only by the above, a three-dimensional image display device that displays a three-dimensional image in a very short time, at low cost, and easily can be manufactured.

(E) Since the direction of the diffracted light can be controlled only by controlling the light shielding pattern of the spatial light modulator by the combination of the diffraction grating array and the spatial light modulator, the stereoscopic moving image can be controlled by controlling the spatial light modulator. An image can be displayed.

In particular, the amount of information for displaying a stereoscopic image (in the case of the present invention, only each pixel value of several to several tens of parallax images)
Therefore, there is a possibility of displaying a real-time stereoscopic image by electric transmission or the like and storing stereoscopic image information such as video.

(F) By arranging the optical frequency filter in accordance with each diffraction grating cell, the wavelength of light emitted from the diffraction grating cell can be selected, so that a full-color stereoscopic image can be observed. Becomes

(G) Since the intensity of the diffracted light can be controlled by changing the light transmitting area of the spatial light modulator, even if the spatial light modulator is a binary control device for transmitting / blocking light,
A display device for displaying a stereoscopic image can be realized.

(H) Since the intensity of the diffracted light can be controlled by changing the light transmittance of the spatial light modulator, the spatial light modulator has a resolution of the size of the divided region of the diffraction grating cell. If so, a display device for displaying a stereoscopic image can be realized.

(I) Further, since a surface relief type diffraction grating can be used as the diffraction grating, mass production can be performed by inexpensive and simple production by a method such as embossing. It is also easy to make optically.

That is, more specifically, the size of the diffraction grating array can be increased. As a result, a volume phase type diffraction grating can also be manufactured, thereby providing wavelength selectivity and significantly improving diffraction efficiency. Further, it is possible to express the diffraction grating in a continuous tone, so that the image quality is improved as compared with a binary rectangular pattern.

As described above, by applying the diffraction grating array of this embodiment to various types of three-dimensional image display devices, it is possible to observe a three-dimensional image having a wide viewing area both vertically and horizontally when observing a three-dimensional image. In addition, since the output area of the diffracted light is limited, it is possible to obtain an effect that the observer can easily recognize the area where the stereoscopic image can be observed.

When a three-dimensional image display device (other than a three-dimensional television) is manufactured, the mask pattern of the light-shielding layer (printing layer) formed on the surface can be obtained by using the mass-produced diffraction grating array of this embodiment. Only change only
A three-dimensional image display device can be manufactured in a very short time and at low cost.

The present invention is not limited to the above embodiment, but can be implemented in the following manner.

(A) In the above embodiment, the case where a diffraction grating cell having a function of condensing light is used as the diffraction grating cell is described. However, the present invention is not limited to this. In the case of using a diffraction grating cell having the above, the same effect can be realized by implementing the same concept as described above.

FIG. 13 is a schematic diagram of an optical system showing an example of a method for producing a diffraction grating having a function of diverging light by two-beam interference. As shown in FIG. 13, a laser beam generated from a laser light source and reflected by a mirror is split into two by a half mirror, one of which is incident on a photosensitive material as parallel light through a lens system. At the position, the other laser beam is reflected by a mirror and is incident as divergent light through a lens system. As a result, interference fringes due to the two lights are recorded in the photosensitive material. By performing such an operation while changing the position of the photosensitive material, a diffraction grating array having interference fringes recorded on the entire surface is obtained. If the diffraction grating array is a surface relief type, duplication by embossing can be easily performed.

FIG. 14A is a side view showing the relationship between incident light and diffracted light of a diffraction grating cell having a function of condensing light.
FIG. 14B is a side view showing a relationship between incident light and diffracted light of a diffraction grating cell having a function of diverging light.

(B) In the above-described embodiments of FIGS. 7 and 12, the case where the light-shielding layer is provided has been described. However, the present invention is not limited to this, and the same effect as described above can be realized when the light-transmitting layer is provided. It is.

(C) In the embodiment of FIGS. 7 and 12, the case where the diffraction grating is used in a reflection type will be described.
In the embodiment of FIG. 8, the case where the diffraction grating is used in the transmission type has been described. However, the present invention is not limited to this, and the diffraction grating may be used in any of the reflection type and the transmission type.

[0101]

As described above, according to the diffraction grating array and the three-dimensional image display device using the same according to the present invention, the thickness of the diffraction grating is gradually reduced and the interval between the diffraction gratings is gradually reduced inside the cell. A plurality of diffraction grating cells, each having a function of diverging or condensing light, are arranged on a planar substrate, and the diffraction grating cells are provided with a gradient of a grating (or a gradient of a grating and a grating). (Intervals) are spatially divided in the horizontal direction (or the horizontal and vertical directions), and each divided region is formed as a diffraction grating array corresponding to each parallax image (one direction or two directions). A grid array is provided as a basic device to display a stereoscopic image having parallax only in the horizontal direction (or both in the horizontal and vertical directions).
It is possible to easily display a stereoscopic image having parallax in the vertical direction, and it is also easy to produce optically, and mass production is possible at low cost.

Further, in this case, a diffraction grating having a function of diverging or condensing light is used.
It is possible to arbitrarily divide the viewing area, and to give a smooth three-dimensional effect when the viewpoint is moved.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a diffraction grating cell.

FIG. 2 is a schematic view showing one embodiment of a diffraction grating array according to the present invention.

FIG. 3 is a plan view showing an example of a diffraction grating cell in the embodiment.

FIG. 4 is a plan view showing another example of the diffraction grating cell in the embodiment.

FIG. 5 is a schematic diagram for explaining the state of analysis in a minute area of the diffraction grating cell in the embodiment.

FIG. 6 is a schematic diagram of an optical system showing an example of a method for manufacturing a diffraction grating having a function of condensing light by two-beam interference in the embodiment.

FIG. 7 is a schematic diagram showing a configuration example of a display to which a diffraction grating array according to the present invention is applied.

FIG. 8 is a schematic diagram showing a configuration example of a stereoscopic television to which the diffraction grating array according to the present invention is applied.

FIG. 9 is an exemplary diagram for explaining a correspondence relationship with an original subject in the stereoscopic television.

FIG. 10 is a schematic diagram for explaining a correspondence relationship with an original subject in the stereoscopic television (in the case of full color).

FIG. 11 is a schematic diagram showing an example of producing a three-dimensional hard copy to which the diffraction grating array according to the present invention is applied.

FIG. 12 is a schematic diagram showing a configuration example of a three-dimensional hard copy to which the diffraction grating array according to the present invention is applied.

FIG. 13 is a schematic view of an optical system showing an example of a method for producing a diffraction grating having a function of diverging light by two-beam interference in another embodiment of the present invention.

FIG. 14 is a side view showing a relationship between incident light and diffracted light of a diffraction grating cell having a function of condensing and diverging light.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Diffraction grating cell, 2 ... Substrate, 11 ... Diffraction grating array,
11A: resin layer (diffraction grating forming layer), 11B: reflection layer,
12: color filter layer, 13: light shielding layer (printing layer),
21: diffraction grating array, 22: liquid crystal display element, 23: color filter layer, 24: subject, 25: camera, 31
... Parallax image, 32 ... Computer, 33 ... Printer, 34 ... Diffraction grating array, 35 ... Three-dimensional hard copy,
41: diffraction grating array, 41A: resin layer (diffraction grating forming layer), 41B: reflection layer, 42: protective layer, 43: light shielding layer (ink layer).

Claims (20)

(57) [Claims] 1. A diffraction grating having a function of diverging or condensing light is formed inside a cell by forming a diffraction grating in which the thickness of the diffraction grating is gradually reduced and the interval is gradually reduced. A plurality of diffraction grating cells are spatially divided in a horizontal direction in a region where the gradient of the grating is close, and each divided region corresponds to a pixel of each parallax image (one direction). A diffraction grating array, characterized in that: 2. The diffraction grating array according to claim 1, wherein a Fresnel zone plate having an off-axis imaging function is used as the diffraction grating. 3. An apparatus for displaying a three-dimensional image, wherein the diffraction grating array according to claim 1 is provided as a basic device, and a three-dimensional image having parallax only in a horizontal direction is displayed. Image display device. 4. The substrate according to claim 3, wherein, in each divided region of the diffraction grating cell, only a diffraction grating having an area proportional to the brightness of a corresponding pixel of a corresponding parallax image is formed on the substrate. 3D image display device. 5. A light-shielding layer or a light-transmitting layer is provided on the substrate surface such that light is transmitted only in an area proportional to the brightness of a corresponding pixel of a corresponding parallax image in each divided region of the diffraction grating cell. 4. The device according to claim 3, wherein
3. The stereoscopic image display device according to 1. 6. A three-dimensional image can be displayed by controlling the intensity of light incident or emitted at a position corresponding to each divided region of the diffraction grating cell by a spatial light modulator. Item 3. The stereoscopic image display device according to item 3. 7. A full-color image can be displayed by selecting a wavelength of light at a position corresponding to each divided region of the diffraction grating cell by an optical frequency filter. 3D image display device. 8. The grid spacing is calculated by the following equation:
A set of three diffraction grating cells having a grid interval corresponding to each of the colors R, G, and B, and based on the value of R of the corresponding pixel of the corresponding parallax image, each of the divided areas of the cell for R. Is controlled by a spatial light modulator, and the wavelength of R light is selected by an optical frequency filter, and this is selected for each color of R, G, B, and all pixels of all parallax images. By performing the same operation,
4. The three-dimensional image display device according to claim 3, wherein a full-color three-dimensional image can be displayed. _{λ = d x (sinβ x -sinθ} x) λ = d y (sinβ y -sinθ y) (λ: wavelength of light, d _x: X component of the lattice spacing, d _y: Y component of the lattice spacing, theta _x: Incident angle in XZ plane, θ _y : Y
-Angle of incidence in the Z plane, β _x : diffraction angle in the XZ plane, β
_y : diffraction angle in the YZ plane) 9. The spatial light modulation device according to claim 9, wherein in each of the divided regions of the diffraction grating cell, an area proportional to the brightness of a corresponding pixel of a corresponding parallax image is set as a transmission portion by a spatial light modulator. 4. The stereoscopic image display device according to 3. 10. A spatial light modulation device in each of the divided regions of the diffraction grating cell, wherein a transmittance proportional to the brightness of a corresponding pixel of a corresponding parallax image is realized by a spatial light modulator. 3. The stereoscopic image display device according to 1. 11. A diffraction grating having a function of diverging or condensing light is formed inside a cell by forming a diffraction grating in which the thickness of the diffraction grating is gradually reduced and the interval is gradually reduced. A plurality of diffraction grating cells are spatially divided in a region where the gradient of the grating and the grating interval are close to each other in the horizontal direction and the vertical direction, and each of the divided regions is divided into the respective parallax images (two directions). A diffraction grating array corresponding to pixels. 12. The diffraction grating array according to claim 11, wherein a Fresnel zone plate having an off-axis imaging function is used as the diffraction grating. 13. An apparatus for displaying a three-dimensional image, comprising the diffraction grating array according to claim 11 as a basic device, and displaying a three-dimensional image having parallax in both horizontal and vertical directions. 3D image display device. 14. The substrate according to claim 13, wherein in each divided region of the diffraction grating cell, only a diffraction grating having an area proportional to the brightness of a corresponding pixel of a corresponding parallax image is formed on the substrate. 3D image display device. 15. A light-shielding layer or a light-transmitting layer is provided on the substrate surface such that light is transmitted only in an area proportional to the brightness of a corresponding pixel of a corresponding parallax image in each divided region of the diffraction grating cell. 2. The device according to claim 1, wherein
4. The stereoscopic image display device according to 3. 16. The spatial light modulator controls the intensity of light incident or emitted at a position corresponding to each divided region of the diffraction grating cell, and converts the wavelength of light at a position corresponding to each divided region of the cell to light. 14. The three-dimensional image display device according to claim 13, wherein a single-color three-dimensional image can be displayed by selecting with a frequency filter. 17. A full-color image can be displayed by selecting a wavelength of light at a position corresponding to each divided region of the diffraction grating cell by using an optical frequency filter. 3D image display device. 18. The grid spacing is calculated by the following equation:
A set of three diffraction grating cells having a grid interval corresponding to each of the colors R, G, and B, and based on the value of R of the corresponding pixel of the corresponding parallax image, each of the divided areas of the cell for R. Is controlled by a spatial light modulator, and the wavelength of R light is selected by an optical frequency filter, and this is selected for each color of R, G, B, and all pixels of all parallax images. By performing the same operation,
14. The three-dimensional image display device according to claim 13, wherein a full-color three-dimensional image can be displayed. _{λ = d x (sinβ x -sinθ} x) λ = d y (sinβ y -sinθ y) (λ: wavelength of light, d _x: X component of the lattice spacing, d _y: Y component of the lattice spacing, theta _x: Incident angle in XZ plane, θ _y : Y
-Angle of incidence in the Z plane, β _x : diffraction angle in the XZ plane, β
_y : diffraction angle in the YZ plane) 19. The spatial light modulation device according to claim 19, wherein in each of the divided regions of the diffraction grating cell, an area proportional to the brightness of a corresponding pixel of a corresponding parallax image is set as a transmission portion by a spatial light modulator. 14. The three-dimensional image display device according to 13. 20. The spatial light modulator according to claim 13, wherein in each of the divided areas of the diffraction grating cell, a transmittance proportional to the brightness of a corresponding pixel of a corresponding parallax image is realized by a spatial light modulator. 3. The stereoscopic image display device according to 1.