JP2011013456A - Display device and display control method - Google Patents

Abstract

Provided are a display device and a display control method capable of displaying a three-dimensional image by a high-resolution hologram with a simple configuration.
A plurality of display regions 1a are arranged side by side on a flexible display sheet 1, and each display region 1a has a predetermined wavelength of incident light due to a light interference effect caused by Fabry-Perot interference of light incident from the outside. And a light source unit 2 that irradiates reference light to the interference fringes formed in the display region 1a. The control unit 10 controls the reflectance of a specific display region 1a to form interference fringes. The display area 1a is divided into a plurality of groups, and the control unit 10 forms interference fringes constituting one image using the display area 1a of one group. Further, the reference light is irradiated to the interference fringes formed in the display area 1a.
[Selection] Figure 1

Description

  The present invention relates to a display device that displays a stereoscopic image using a hologram technique, and a display control method for displaying a stereoscopic image by the display device.

  Conventionally, as an apparatus for displaying a stereoscopic image using hologram technology, for example, an interference pattern of a plurality of images is recorded in advance on a hologram screen, and each image on the hologram screen is sequentially reproduced by laser light. An apparatus for projecting a moving image is known (see, for example, Patent Document 1). In addition, for example, an apparatus that projects a moving image by driving a light diffraction array composed of a diffractive MEMS to change a hologram is known (for example, see Patent Document 2).

JP 2000-66136 A JP 2004-272000 A

By the way, there is always a demand for higher image quality for devices that display moving images, and stereoscopic images are no exception. However, as described above, for example, in the method of recording interference patterns of a plurality of images on one hologram screen, there is a limit to increasing the resolution of one image. Further, for example, in the method of changing the hologram by driving the optical diffraction array as described above, it is necessary to achieve high resolution and high speed of the optical diffraction array, and there is a great technical barrier. Furthermore, in any of the above devices, it has been inevitable that the device becomes a complicated and large-scale device.
Accordingly, an object of the present invention is to provide a display device and a display control method capable of displaying a stereoscopic image using a high-resolution hologram with a simple configuration.

In order to achieve the above object, according to the present invention, a plurality of display areas for forming interference fringes are provided side by side on a flexible sheet, and each display area has optical interference caused by Fabry-Perot interference of light incident from the outside. A reflection layer that reflects light having a predetermined wavelength of incident light, and a piezoelectric body that deforms according to an electric field in the surroundings to change the reflectance of the reflection layer. The selection unit that selects the piezoelectric body corresponding to the region, and the selection unit selects the specific piezoelectric body and applies an electric field to the piezoelectric body to deform the piezoelectric body according to the difference in reflectance in the reflective layer. A control unit that forms interference fringes in the display area; and a light source that irradiates reference light to the interference fringes formed in the display area, wherein the plurality of display areas are divided into a plurality of groups, and the control One by part By using the display area of the group to form an interference fringe forming one image, for each group by the light source, irradiating the reference beam to the interference fringes formed in the display region, characterized by.
According to this configuration, the function of reflecting light of a predetermined wavelength by the optical interference effect due to Fabry-Perot interference, which is the same principle as that having the characteristics of a physical structure for accurately generating the interference phenomenon of light waves The display area of the sheet provided with is divided into a plurality of groups, and interference fringes are formed for each group and the reference light is emitted from the light source. Can project. For this reason, after projecting a hologram of one image using one group and then projecting another image using another group, the hologram can be sequentially changed to display a stereoscopic image by the hologram. . In this case, by switching a plurality of groups, it is possible to secure a long time for forming the interference fringes in one group, so that it is easy to increase the resolution. In other words, since interference fringes need only be formed while the hologram is projected by another group, even if it takes time to form interference fringes due to higher resolution, there is a situation in which interference fringes cannot be formed. Absent. As a result, dense interference fringes can be formed with high resolution. Further, since the hologram can be switched in a short time, the hologram can be changed at high speed, and a smooth stereoscopic image can be displayed. In particular, since a hologram has a characteristic that an afterimage tends to remain, by projecting the next hologram while leaving an afterimage of the previously projected hologram, a stereoscopic image that changes more smoothly can be displayed and reproduced. Furthermore, it does not require a special mechanism for speeding up the formation of interference fringes, and can be easily realized with a simple configuration.

In the above configuration, the control unit continuously performs an operation of forming interference fringes constituting one image using the display area of one group while switching the target group, and the control unit performs each group. Each time an interference fringe is formed in the display area, the group irradiated with the reference light by the light source may be switched.
Further, the sheet is configured by a rectangle, and in the rectangular sheet, the plurality of display areas are divided into a plurality of band-shaped areas arranged along one side of the sheet, and each group is configured by a plurality of band-shaped areas. The band-like regions may be arranged so that regions constituting different groups are adjacent to each other.

In the present invention, a plurality of display areas for forming interference fringes are provided side by side on a flexible sheet, and each display area is provided with an incident light by an optical interference effect due to Fabry-Perot interference of light incident from the outside. A display layer configured to include a reflective layer that reflects light of a predetermined wavelength and a piezoelectric body that deforms according to an electric field in the surroundings to change the reflectance of the reflective layer, By selecting the piezoelectric body corresponding to the display area and applying an electric field to the selected specific piezoelectric body to deform it, an interference fringe is formed in the display area due to a difference in reflectance in the reflective layer, The display area is divided into a plurality of groups, and interference fringes constituting one image are formed using the display areas of one group, and reference light from the light source is applied to the interference fringes formed in the display area for each group. Irradiation.
According to this method, the function of reflecting light of a predetermined wavelength by the optical interference effect by Fabry-Perot interference, which is the same principle as that having the characteristics of a physical structure for accurately generating the interference phenomenon of light waves. The display area of the sheet with a plurality of groups is divided into a plurality of groups, and interference fringes are formed for each group and the reference light is emitted from the light source. 3D images can be displayed using holograms. In this case, by switching a plurality of groups, it is possible to secure a long time for forming the interference fringes in one group, so that it is easy to increase the resolution, and the hologram is remarkably shorter than the time required for forming the interference fringes. Since the hologram can be changed at high speed with a simple configuration, a smooth stereoscopic image can be displayed.

  According to the present invention, since the stereoscopic image by the hologram is displayed at high speed by switching the group to which the reference light is irradiated, the time for forming the interference fringes can be ensured for a long time, so that the resolution can be easily increased. In addition, since a smooth stereoscopic image can be displayed and a special mechanism for speeding up the formation of interference fringes is not required, it can be easily realized with a simple configuration.

It is a figure which shows schematic structure of the video display apparatus which concerns on embodiment of this invention. It is a functional block diagram which shows the structure of a video display apparatus. It is a flowchart which shows the display operation using a display sheet. It is principal part sectional drawing which shows the structure of a display sheet. It is a principal part perspective view which shows the arrangement | positioning state of each part of a display sheet. It is a principal part top view which shows the arrangement | positioning state of the piezoelectric element for polarization, and wiring. It is a figure explaining the mode of a deformation | transformation of the piezoelectric element for a drive.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a configuration of a video display apparatus 100 according to an embodiment to which the present invention is applied.
The video display device 100 shown in FIG. 1 includes a display sheet 1 (sheet), a light source unit 2 (light source), and a control unit 10 that controls the display sheet 1 and the light source unit 2.
FIG. 1 shows the appearance of the display sheet 1. The display sheet 1 is a rectangular sheet, and on its surface, a large number of display areas 1 a are arranged in a matrix so as to be parallel to each side of the display sheet 1.
The display area 1a is driven by a driving piezo element 140 (FIG. 4) or the like provided inside the display sheet 1 as described later under the control of the control unit 10, so that the reflectance for reflecting external light changes. To do. The reflectance in each display area 1a can be changed independently under the control of the control unit 10. Then, by controlling the reflectance of the plurality of display areas 1a individually under the control of the control unit 10, interference fringes based on the light interference phenomenon can be formed in the display sheet 1 in a space away from the display surface. . When this interference fringe is irradiated with reference light by the light source unit 2, a hologram is projected.

The display area 1a provided side by side on almost the entire surface of the display sheet 1 is assigned to a plurality of groups. In the present embodiment, as an example, a case where two groups (first group and second group) are assigned will be described.
In the display sheet 1, a plurality of band-like regions 1 b (band-like regions) extending in the short side direction (lateral direction in FIG. 1) of the display sheet 1 are set. Each band-like area 1b includes a large number of display areas 1a arranged vertically and horizontally, and the entire band-like area 1b is rectangular. And these some strip | belt-shaped area | region 1b is located in a line with the long side direction (vertical direction in FIG. 1) of the display sheet 1, and the strip | belt-shaped area | region 1b which belongs to the 1st group, and the strip | belt-shaped area | region 1b which belongs to a 2nd group are alternately. Are lined up. Further, the number of the band-like regions 1b belonging to the first group is the same as the number of the band-like regions 1b belonging to the second group.

As will be described later, the control unit 10 changes the reflectance of each display area 1a to form interference fringes in the band-like area 1b. The display area 1a is configured to reflect outside light of a predetermined wavelength by the optical interference effect due to Fabry-Perot interference, and at least switches between two states of a high reflectance state and a very low reflectance state. Is possible. Moreover, it is good also as a structure which changes the reflectance of the display area 1a in multiple steps.
In the display sheet 1, the interference fringes are formed for each group. That is, interference fringes for projecting a hologram of one image are formed using the entire band-like region 1b constituting one group.
A selection circuit 11 is provided on the periphery of the display sheet 1, and the control unit 10 is connected to the selection circuit 11. The selection circuit 11 is a circuit that selects a specific display area 1 a from among a large number of display areas 1 a provided on the display sheet 1 according to the control of the control unit 10. The reflectance of the displayed area 1a is adjusted.

The control unit 10 adjusts the reflectance of the display area 1a provided on the display sheet 1 for each group. That is, the control unit 10 performs the operation of selecting the display area 1a by the selection circuit 11 and adjusting the reflectance on all the display areas 1a constituting the strip-like area 1b belonging to the first group. Thereby, the control part 10 displays one image in the strip | belt-shaped area | region 1b which belongs to 1st group.
The band-like region 1b belonging to the first group is arranged on the entire display sheet 1 with a gap as shown in FIG. 1, so that if one image is displayed on the many band-like regions 1b, so-called interlaced display is performed. In the same manner, it seems that the image is displayed on the entire display sheet 1 without a sense of incongruity.

The control unit 10 can also switch the group to be controlled from the first group to the second group. That is, the control unit 10 performs the operation of selecting the display area 1a by the selection circuit 11 and adjusting the reflectance to all the display areas 1a constituting the band-like area 1b belonging to the second group. Thereby, the control part 10 displays one image in the strip | belt-shaped area | region 1b which belongs to 2nd group.
Similar to the first group, the band-like region 1b belonging to the second group is arranged on the entire display sheet 1 with a gap as shown in FIG. 1, so that one image is displayed on the many band-like regions 1b. Then, like the so-called interlaced display, it appears that the image is displayed on the entire display sheet 1 without a sense of incongruity.

As described above, in the configuration of the display sheet 1, it is possible to make it appear that an image is displayed on the entire display sheet 1 regardless of whether the first group or the second group is used.
Therefore, the video display apparatus 100 displays a moving image by alternately performing display using the first group and display using the second group.
That is, when video data (for example, 30 frames / second) is input from an external device (not shown), the video display device 100 extracts an image of each frame constituting the video data, and images of successive frames. Are alternately displayed by the first group and the second group. In this example, display is performed 15 times per second in the first group of band-like regions 1b, and the same applies to the second group. As a result, the time required to adjust the display state of each display area 1a in the band-like area 1b is half (15 frames / second) of the frame rate of video data (30 frames / second in this example). While ensuring the time required for adjusting the display state of the display area 1a, the entire display sheet 1 can perform smooth display at 30 frames / second.

  The video display apparatus 100 does not display the image itself on the display sheet 1, but forms interference fringes constituting a hologram by adjusting the reflectance in each display region 1a. The process of forming the interference fringes on the entire display sheet 1 can be performed at a high speed because it is an operation of applying an electric field to the piezoelectric body and deforming it as will be described later. . The video display device 100 forms a large number of interference fringes in a short time by forming interference fringes corresponding to a plurality of frames constituting an image while switching a plurality of groups of band-like regions 1b, and has a high frame rate. A smooth video (moving image) hologram can be realized.

The light source unit 2 is a light source that irradiates the display sheet 1 with coherent light. In the present embodiment, as an example, the light source unit 2 includes a laser light source 21, and the reference light 22 emitted from the laser light source 21 is arbitrarily set on the display sheet 1. Irradiate the area.
The light source unit 2 is connected to the control unit 10, and the control unit 10 controls the irradiation start / stop timing and the irradiation range in the display sheet 1. The light source unit 2 can scan each display area 1 a configured on the display sheet 1 and sequentially irradiate each display area 1 a with the reference light 22.
The control unit 10 controls the light source unit 2 to perform an operation of scanning the first group of band-like areas 1b and an operation of scanning the second group of band-like areas 1b to form interference fringes in the band-like area 1b. Execute according to. Specifically, after the interference fringes are formed in the first group of band-like areas 1b, the control unit 10 causes the reference light 22 from the light source unit 2 to scan the display area 1a constituting the first group of band-like areas 1b. Irradiate. During this time, the control unit 10 performs an operation of forming interference fringes in the second group of band-like regions 1b. When the formation of interference fringes on the second group of band-like regions 1b is completed, the control unit 10 controls the light source unit 2 to irradiate the second group of band-like regions 1b with the reference light 22. In this way, the control unit 10 sequentially executes the formation of the interference fringes and the irradiation of the reference light 22 while alternately switching between the first group and the second group. Project and display a stereoscopic image by hologram.

FIG. 2 is a functional block diagram showing the configuration of the video display device 100.
As described above, the display sheet 1 includes the selection circuit 11 that selects a specific display area 1a from among a large number of display areas 1a provided on the display sheet 1. Here, each display area 1a is assigned to either the first group or the second group, and is controlled for each group. Therefore, the selection circuit 11 selects the specific display area 1a from the display areas 1a belonging to the first group and the specific display area 1a from the display areas 1a belonging to the second group. And a selection unit 11b.

The control unit 10 includes a first control unit 210 connected to the selection unit 11a and a second control unit 220 connected to the selection unit 11b.
The control unit 10 generates an image data for one screen by processing an external interface (I / F) 201 connected to an external device (not shown) and video data input via the external interface 201. The display information processing unit 202 outputs the generated image data to each of the first control unit 210 and the second control unit 220.
More specifically, the display information processing unit 202 extracts frames constituting the input video data, and generates image data for one screen constituting each frame. This image data is, for example, data obtained by cutting out a frame of video data and converting the resolution according to the number of display areas 1 a in the display sheet 1. In addition, when the input image data is full-color data, the display information processing unit 202 converts (subtracts) the extracted frame data into binary data or grayscale data, and the first control unit 210 and output to the second control unit 220.

  The first control unit 210 obtains image data input from the pulse generation unit 211 that generates a pulse for driving the display region 1a and the display information processing unit 202, and the pixels (pixels) constituting the image data ) To the display area 1a of the display sheet 1 is provided. The display information supply unit 212 reflects each of the display regions 1a in order to form the interference fringes corresponding to the image data input from the display information processing unit 202 using all the band-like regions 1b constituting the first group. Determine the state. Since the reflection state of the display area 1a can be switched in two stages as described above, for example, the display information supply unit 212 calculates and determines the reflectance of each display area 1a from the input image data. . Information indicating the reflectance of each display region 1 a determined by the display information supply unit 212 is input to the piezo signal generation unit 213 together with the pulse generated by the pulse generation unit 211. Here, the information indicating the reflectance of each display region 1a is sequentially input to each display region 1a in synchronization with the pulse generated by the pulse generator 211 from the display information supply unit 212 to the piezo signal generation unit 213. May be.

The piezo signal generator 213 sequentially selects the first group of display areas 1a by sending a control signal to the selector 11a in accordance with the pulse input from the pulse generator 211. Then, the piezo signal generation unit 213 controls the reflectance of the display area 1a selected by the selection unit 11a according to information input from the display information supply unit 212.
Specifically, a voltage necessary for applying an electric field to the display region 1a in order to change the reflectance of the display region 1a is supplied from the piezoelectric vibration voltage unit 214 to the piezo signal generator 213. The piezo signal generation unit 213 uses the voltage supplied from the piezo vibration voltage unit 214 in order to set the reflectance of the display area 1a selected by the selection unit 11a to the reflectance determined by the display information supply unit 212. Then, an electric field is applied to the display area 1a.
Thereafter, the piezo signal generation unit 213 controls the selection unit 11a at a timing synchronized with the pulse input from the pulse generation unit 211, selects the next display region 1a, and the reflectance of the newly selected display region 1a. Is applied to the display information supply unit 212 to achieve the reflectivity. By performing the above operation on all the display areas 1a constituting the first group of band-like areas 1b, interference fringes corresponding to one image data are formed.

The second control unit 220 is configured in the same manner as the first control unit 210.
The second control unit 220 is input from the display information processing unit 202 in the same manner as the pulse generation unit 221 that generates a pulse for driving the display area 1 a and the display information supply unit 212 as in the pulse generation unit 211. A display information supply unit 222 that performs processing of acquiring image data and assigning pixels constituting the image data to the display area 1a of the display sheet 1; The display information supply unit 222 forms the interference fringes corresponding to the image data input from the display information processing unit 202 using all the band-like regions 1b constituting the second group, so that the reflection state of each display region 1a To decide. Since the reflection state of the display area 1a can be switched in two steps as described above, for example, the display information supply unit 222 calculates and determines the reflectance of each display area 1a from the input image data. . Information indicating the reflectivity of each display region 1 a determined by the display information supply unit 222 is input to the piezo signal generation unit 223 together with the pulse generated by the pulse generation unit 221. Here, information indicating the reflectivity of each display region 1a is sequentially input to each display region 1a in synchronization with the pulse generated by the pulse generation unit 221 from the display information supply unit 222 to the piezo signal generation unit 223. May be.

The piezo signal generator 223, like the piezo signal generator 213, sequentially selects the first group of display areas 1a by sending a control signal to the selector 11b according to the pulse input from the pulse generator 221. Let Then, the piezo signal generation unit 223 controls the reflectance of the display area 1a selected by the selection unit 11b according to information input from the display information supply unit 222.
Specifically, the piezoelectric signal generator 223 is supplied with a voltage necessary for applying an electric field to the display region 1 a in order to change the reflectance of the display region 1 a from the piezo vibration voltage unit 224. The piezo signal generation unit 223 uses the voltage supplied from the piezo vibration voltage unit 224 in order to set the reflectance of the display area 1a selected by the selection unit 11b to the reflectance determined by the display information supply unit 222. Then, an electric field is applied to the display area 1a.
Thereafter, the piezo signal generation unit 223 controls the selection unit 11b at a timing synchronized with the pulse input from the pulse generation unit 221, causes the next display region 1a to be selected, and the reflectance of the newly selected display region 1a. Is applied to the display information supply unit 212 to achieve the reflectivity. By performing the above operation on all the display areas 1a constituting the second group of band-like areas 1b, interference fringes corresponding to one image data are formed.

  Furthermore, the control unit 10 includes a light source control unit 203 that controls the light source unit 2. The light source control unit 203 is based on the timing at which the display information processing unit 202 generates image data for one frame from the video data and outputs the image data to the first control unit 210 and the second control unit 220. 2 determines whether the range in which the reference light 22 (FIG. 1) is irradiated is the first group or the second group. Then, the light source control unit 203 outputs control information to the light source unit 2, so that the light source unit 2 refers to the timing at which the first control unit 210 and the second control unit 220 each form an interference fringe in the band-shaped region 1 b. The range in which the light 22 is irradiated is switched. The light source unit 2 irradiates the reference light 22 so as to scan the belt-like region 1b constituting the first group or the belt-like region 1b constituting the second group in accordance with the control information input from the light source control unit 203.

  Thereby, interference fringes corresponding to image data for one frame are alternately formed in the first group of strip regions 1b and the second group of strip regions 1b of the display sheet 1, and the interference of these first groups. Since the reference light 22 is alternately applied to the fringes and the second group of interference fringes, a hologram of each frame of the video data is sequentially projected in front of the display sheet 1, and as a result, a stereoscopic image using the hologram Can be projected.

FIG. 3 is a flowchart showing the operation of the video display device 100.
As shown in FIG. 3, the control unit 10 of the video display device 100 first acquires video data via the external interface 201, and inputs this video data to the display information processing unit 202 (step S11).
The control unit 10 extracts each frame constituting the input video data by the display information processing unit 202, selects the top frame among them (step S12), and further displays a group to be displayed (hereinafter referred to as a display group). The first group is selected (step S13).
The control unit 10 outputs image data for one frame extracted from the video data to the side corresponding to the display group from the display information processing unit 202 to the first control unit 210 or the second control unit 220, and The control unit 210 or the second control unit 220 forms interference fringes in the band-like region 1b of the display group (step S14). Further, the control unit 10 switches the irradiation range of the light source unit 2 by the function of the light source control unit 203, and irradiates the reference light 22 so as to scan the band-like region 1b of the display group (step S15). Thereby, an interference fringe is formed on the display sheet 1, the reference light 22 is irradiated on the interference fringe, and a stereoscopic image using a hologram is projected.

Here, the control unit 10 determines whether or not the final frame of the video data has been projected (step S16). If the projection has not yet been performed to the final frame (step S16; No), the control unit 10 determines the frame extracted from the video data. The next frame is selected (step S17), and another group different from the currently selected display group is selected as a display group (step S18), and the process returns to step S14. As a result, a plurality of frames constituting the video data are sequentially projected as a stereoscopic image while switching the display group.
When the video data is projected up to the final frame (step S16; Yes), the control unit 10 ends this process.

  In addition, when forming an interference fringe in the band-like region 1b of the display group in step S14, the control unit 10 may perform an operation of once resetting the reflectance of all the display regions 1a to the initial state. By performing this operation, all the display areas 1a are in the same state. Therefore, in the subsequent operation of controlling the reflectance of each display area 1a, it is not necessary to consider the state of the previous display area 1a. There is an advantage that the speed and efficiency can be improved.

Next, the configuration of the display sheet 1 on which interference fringes are formed in the video display device 100 will be described in detail.
FIG. 4 is a cross-sectional view of the main part showing the configuration of the display sheet 1.
The display sheet 1 is configured as a flexible sheet. For example, the display sheet 1 can be bent as shown in FIG. 1 or can be bent. A selection circuit 11 is provided at the edge of the display sheet 1, and a control unit 10 that controls the display state of the display sheet 1 is connected to the selection circuit 11.
The surface of the display sheet 1 is covered with a translucent surface layer 150, and the back surface side of the display sheet 1 is composed of a flexible base sheet 101, and the base sheet 101 and the surface layer 150 are interposed between the base sheet 101 and the surface layer 150. It has a configuration that houses each part.

The surface layer 150 is a transparent or translucent layer having translucency, and may be colored (including white) or colorless. The surface layer 150 is made of, for example, a synthetic resin. The lower surface of the surface layer 150, that is, the surface on the base sheet 101 side functions as a half mirror having a smooth and high reflectance, and reflects light incident from below.
The base sheet 101 is a sheet having flexibility and a predetermined tensile strength capable of supporting each part described later. Although the transparency of the base sheet 101 is arbitrary, it is preferably opaque or translucent so as not to disturb the display on the surface (surface layer 150 side) of the display sheet 1. As the base sheet 101, a synthetic resin sheet or a sheet made of an inorganic material such as glass can be used.
In the following description, for the sake of convenience, the surface layer 150 side will be described as the upper side and the base sheet 101 side will be described as the lower side. Of course, the installation state and the installation direction of the display sheet 1 when the display sheet 1 is used are not limited at all.

  A plurality of polarization piezo elements 120 are disposed on the upper side of the base sheet 101. The polarization piezo element 120 is a plate, a film, or a layer made of a ferroelectric (for example, lead zirconate titanate, barium titanate, etc.). The polarization piezo element 120 is connected to the X-direction wiring 111 disposed on the lower side and the Y-direction wiring 112 disposed on the upper side.

FIG. 5 is a main part perspective view showing the arrangement state of the X direction wiring 111, the Y direction wiring 112, the polarization piezo element 120, and the driving piezo element 140, and FIG. 6 shows the polarization piezo element 120 and each wiring. It is a principal part top view which shows a connection state.
As shown in FIGS. 5 and 6, the polarization piezo elements 120 of the present embodiment are formed in a square shape, and are arranged in a matrix form on the substantially entire surface of the display sheet 1 with predetermined intervals in the vertical and horizontal directions. Yes.
An X-direction wiring 111 extending in the width direction of the display sheet 1 is disposed below the polarization piezo element 120. The X-direction wiring 111 is a film or layer made of a conductive material such as metal or carbon, and is electrically connected to the polarization piezo element 120. A plurality of X-direction wirings 111 are provided in parallel with the longitudinal direction of the display sheet 1 corresponding to the polarization piezo elements 120 arranged at a predetermined interval. A plurality of polarization piezo elements 120 arranged in a line along the X-direction wiring 111 is connected to one X-direction wiring 111.

Further, Y-direction wirings 112 extending in the longitudinal direction of the display sheet 1 are arranged side by side in the width direction of the display sheet 1 on the upper side of the polarization piezoelectric element 120. Similar to the X-direction wiring 111, the Y-direction wiring 112 is a thin film made of a conductive material such as metal or carbon, and is electrically connected to the polarization piezo element 120. A plurality of Y-direction wirings 112 are provided in parallel with the width direction of the display sheet 1 corresponding to the polarization piezo elements 120 arranged at a predetermined interval. A single Y-direction wiring 112 is connected to a plurality of polarization piezo elements 120 arranged in a line along the Y-direction wiring 112.
The Y direction wiring 112 constitutes the wiring unit 110 together with the X direction wiring 111 and a transparent wiring 113 described later.
Here, the X-direction wiring 111 and the Y-direction wiring 112 constitute a holding wiring portion, and the Y-direction wiring 112 and the transparent wiring 113 constitute a driving wiring portion.

All the X direction wirings 111 and the Y direction wirings 112 are respectively connected to the selection circuit 11 (FIG. 1).
The selection circuit 11 selects one or a plurality of X direction wirings 111 from among the plurality of X direction wirings 111 under the control of the control unit 10, and connects the selected X direction wirings 111 to the control unit 10. The selection circuit 11 selects one or a plurality of Y-direction wirings 112 from the plurality of Y-direction wirings 112 and connects the selected Y-direction wirings 112 to the control unit 10. The control unit 10 controls the potentials of the X direction wiring 111 and the Y direction wiring 112 selected by the selection circuit 11 and applies a voltage between the X direction wiring 111 and the Y direction wiring 112.

As shown in FIG. 4, an insulating layer 131 is disposed between the X-direction wiring 111 located below the polarization piezo element 120 and the surface layer 150. The insulating layer 131 is an insulating synthetic resin or the like, and fills the space between the X-direction wiring 111 and the X-direction wiring 111 and between the X-direction wiring 111 and the surface layer 150, and the X-direction It serves to insulate and protect the wiring 111 and the polarization piezo element 120 and the surface layer 150.
Although there is no particular limitation on the color of the insulating layer 131, for example, when a light-shielding material is used, it is possible to prevent excessive reflected light from being emitted from the surface layer 150. That is, a driving piezo element 140 described later may be a light-transmitting material or a light-shielding material, but when a light-transmitting material is used, light incident from the surface layer 150 is used for driving. There is a possibility of reaching the X-direction wiring 111 located below the piezo element and reflecting by the X-direction wiring 111. Here, when the insulating layer 131 is made of a light-shielding material or a material with low translucency, external light hardly reaches the X-direction wiring 111 and the reflected light of the X-direction wiring 111 is reflected on the surface. Since it is not radiated | emitted to the layer 150, there exists an advantage that the extra radiation | emission light radiated | emitted irrespective of the operation | movement of the driving piezo element 140 can be prevented.

Above the piezo element for polarization 120, a drive piezo element 140 (piezoelectric body) is arranged in a matrix so as to correspond to the piezo element for polarization 120.
One driving piezo element 140 corresponds to one display area 1a (FIG. 1).
The driving piezo element 140 is composed of a piezoelectric material, for example, an inorganic piezoelectric material such as lead zirconate titanate, barium titanate, lithium niobate, lithium tantalate, or an organic piezoelectric material such as polyvinylidene fluoride. It is the board or film | membrane or layer comprised by these. As shown in FIG. 5, the driving piezo elements 140 of the present embodiment are formed in a square shape and are arranged in a matrix at predetermined intervals in the vertical and horizontal directions of the display sheet 1.

  Transparent wiring 113 is laid on the upper surface of the driving piezo element 140. The transparent wiring 113 is made of a translucent conductive film (layer) such as indium tin oxide, zinc oxide-based transparent conductive material, magnesium hydroxide-carbon-based transparent conductive material, or the like. . A plurality of transparent wirings 113 are provided side by side in parallel so as to extend in the width direction of the display sheet 1, for example, similarly to the X-direction wirings 111, corresponding to the driving piezo elements 140 arranged at a predetermined interval. All the transparent wirings 113 are connected to the selection circuit 11 (FIG. 1), and any one of the plurality of transparent wirings 113 can be selected by the selection circuit 11.

  Since the transparent wiring 113 is arranged side by side in the same direction as the X-direction wiring 111, when one transparent wiring 113 and one Y-direction wiring 112 are selected, one transparent wiring 113 is located at the intersecting location. The driving piezo element 140 is specified. The selection circuit 11 (FIG. 1) selects one or a plurality of transparent wirings 113 according to the control of the control unit 10 and connects the selected transparent wirings 113 to the control unit 10. The control unit 10 grounds the transparent wiring 113 connected by the selection circuit 11.

  A spacer 141 is disposed between the adjacent driving piezo elements 140 and the driving piezo elements 140. The thickness of the spacer 141 is made of an insulating material such as a synthetic resin and corresponds to the combined thickness of the driving piezo element 140 and the transparent wiring 113 when no electric field is applied. The driving piezo element 140 and the transparent wiring 113 and the spacer 141 form one layer. A space formed between this layer and the Y-direction wiring 112 and between the Y-direction wiring 112 and the Y-direction wiring 112 is filled with an insulating layer 132. The insulating layer 132 is an insulating layer configured similarly to the insulating layer 131. In addition, the spacer 141 separates adjacent transparent wirings 113.

  A dielectric mirror 142 is provided on the transparent wiring 113 above the driving piezo element 140. The dielectric mirror 142 is composed of a single-layer or multilayer dielectric film and functions as a half mirror. That is, the dielectric mirror 142 reflects external light incident on the display sheet 1 through the surface layer 150 to the surface layer 150. The dielectric mirror 142 of the present embodiment is made of aluminum, and the upper surface (surface) of the dielectric mirror 142 is covered with an oxide film 143 to prevent oxidation.

  Since both the lower surface of the dielectric mirror 142 and the surface layer 150 are half mirrors, the interference effect of Fabry-Perot interference on these two surfaces causes the specific light out of the light incident through the surface layer 150 from the outside. The light of the wavelength is emitted outside as reflected light. That is, the dielectric mirror 142 is combined with the surface layer 150 to form a reflective layer, and reflects light having a predetermined wavelength included in incident light. Here, since the wavelength of the reflected light is determined by the thickness (gap) of the space 144 between the dielectric mirror 142 and the surface layer 150, the size of the gap is adjusted according to the wavelength of the color displayed by the display sheet 1. Is preset. In the present embodiment, the size of the gap is set according to the wavelength of the reference light 22 emitted from the light source unit 2.

The lower surface (back surface) of the dielectric mirror 142 is in close contact with the transparent wiring 113, and the transparent wiring 113 is fixed to the upper surface of the driving piezo element 140. Therefore, when the driving piezo element 140 is deformed as will be described later, the dielectric mirror 142 is displaced together with the transparent wiring 113 along with the deformation of the driving piezo element 140, so that the gap between the dielectric mirror 142 and the surface layer 150 is changed. The gap widens. When the gap is enlarged, the reflectivity at the dielectric mirror 142 is remarkably lowered, so that the reflected light to the surface of the display sheet 1 is almost eliminated at this position. If this is viewed from the surface side of the display sheet 1, there are a portion that reflects light of a predetermined wavelength and a portion that hardly reflects, so that an image can be displayed in a predetermined color by controlling each portion.
Hereinafter, an operation of deforming the driving piezo element 140 will be described.

  As shown in FIG. 5, since one Y-direction wiring 112 and one transparent wiring 113 are connected to one driving piezo element 140, the selection circuit 11 performs Y-direction wiring one by one. By selecting 112 and the transparent wiring 113, it is possible to select only one set of Y-direction wiring 112 and only one driving piezo element 140 connected to the transparent wiring 113. Therefore, the selection circuit 11 selects a pair of Y-direction wirings 112 and transparent wirings 113 and connects them to the control unit 10. The control unit 10 applies a positive or negative voltage to the Y-direction wirings 112 and sets the transparent wirings 113. When grounded, an electric field is applied to the specific driving piezo element 140. The driving piezo element 140 is deformed by receiving an electric field between the Y-direction wiring 112 and the transparent wiring 113.

FIG. 7 is a diagram for explaining a state of deformation (drive) of the driving piezo element 140. FIG. 7A is a cross-sectional view of the main part in the vicinity of the driving piezo element 140 when the driving piezo element 140 is not driven, and FIG. 7B is a cross-sectional view of the main part during driving.
In a state where no electric field is applied between the Y-direction wiring 112 and the transparent wiring 113, the driving piezo element 140 maintains the same thickness as the spacer 141 together with the transparent wiring 113 as shown in FIG. Yes. In this case, the gap between the lower surface of the surface layer 150 and the dielectric mirror 142 is a preset value d1.
Here, when an electric field is applied between the Y-direction wiring 112 and the transparent wiring 113, the driving piezo element 140 is deformed in the thickness direction as shown in FIG. The body mirror 142 is displaced downward. In this state, the gap between the lower surface of the surface layer 150 and the dielectric mirror 142 is enlarged, and becomes the size indicated by d2 in the drawing at the largest location.

When the gap is widened as shown in FIG. 7B, the reflectance of the dielectric mirror 142 is reduced and external light is absorbed, so that the amount of reflected light emitted from the surface layer 150 is reduced. Accordingly, since the amount of reflected light can be greatly varied depending on whether or not an electric field is applied to the driving piezo element 140, a portion that reflects light of a predetermined color when the display sheet 1 is viewed from the front side. And a dark part can be mixed, and an image can be displayed on the entire display sheet 1.
As described above, the display sheet 1 has a function of reflecting light having a predetermined wavelength included in incident light due to a light interference effect due to Fabry-Perot interference, and is deformed by applying an electric field to some driving piezo elements 140. By doing so, the reflected light is changed for each position of the driving piezo element 140, and the display based on the intensity of the reflected light or the presence or absence of the reflected light can be performed. In this case, each driving piezo element 140 functions as a display unit (so-called pixel), and can display characters, images, and the like on the display sheet 1 by using external light (reference light).

  Here, when an electric field is applied to the driving piezo element 140, the driving piezo element 140 is electrostatically coupled to the transparent wiring 113 and the Y direction wiring 112, so the Y direction wiring 112 and the transparent wiring 113 are connected to the driving piezo element. There is no need to be directly electrically connected to the element 140. Further, when a voltage is directly applied to the driving piezo element 140, the Y-direction wiring 112 and the transparent wiring 113 may be electrically connected to the driving piezo element 140.

Also, as shown in FIG. 5, since one X-directional wiring 111 and one Y-directional wiring 112 are connected to one polarization piezo element 120, one X-directional wiring 111 is connected. And one Y-direction wiring 112 are selected, the X-direction wiring 111 and the Y-direction wiring are connected to the one set of X-direction wiring 111 and the only piezo element 120 for polarization connected to the Y-direction wiring 112. A voltage can be applied via 112.
Since the polarization piezo element 120 is made of a ferroelectric material, polarization is generated in the polarization piezo element 120 when a voltage is applied to the X direction wiring 111 and the Y direction wiring 112. For example, when a voltage is applied to the polarization piezo element 120 with the X-direction wiring 111 on the low voltage side and the Y-direction wiring 112 on the high voltage side, polarization occurs and negative charges are localized on the upper surface of the polarization piezo element 120. Then, a positive charge is localized on the lower surface of the polarization piezo element 120.

As shown in FIG. 5, since one driving piezo element 140 is located immediately above one polarization piezo element 120, when polarization occurs in the polarization piezo element 120, the driving piezo element 120 just above that is driven. The piezo element 140 is affected by the charge on the surface of the piezo element 120 for polarization. For example, when negative charges are localized on the upper surface of the polarization piezo element 120, an electric field from the transparent wiring 113 toward the polarization piezo element 120 is generated around the drive piezo element 140. At this time, if the transparent wiring 113 is grounded by the control unit 10, a stronger electric field is generated. The driving piezo element 140, which is a piezoelectric body, is deformed by the influence of the electric field generated by the electric charge of the polarization piezo element 120.
When an electric field is generated by the electric charge of the polarization piezo element 120 in a state where the voltage is applied to the Y-direction wiring 112 and the drive piezo element 140 is deformed, the drive piezo element 140 is connected to the polarization piezo element 120. Keep the deformed state due to the electric charge. For this reason, even if the application of the voltage to the Y-direction wiring 112 is stopped, the driving piezo element 140 remains deformed.

The operation in which the first control unit 210 and the second control unit 220 of the control unit 10 (FIG. 2) adjust the reflectance of the display area 1a selected by the selection units 11a and 11b is as follows.
First, a pair of Y-direction wiring 112 and transparent wiring 113 connected to the driving piezo element 140 in the target display area 1a is selected by the selection units 11a and 11b.
When reducing the reflectance in the target display area 1a, the control unit 10 applies an electric field between the selected Y-direction wiring 112 and the transparent wiring 113 by the voltage supplied from the piezo vibration voltage units 214 and 224. To do. As a result, an electric field is applied to the driving piezo element 140 to cause deformation, and the reflectance in the display region 1a becomes low.
Subsequently, the control unit 10 causes the selection units 11a and 11b to select the X-direction wiring 111 connected to the polarization piezo element 120 located immediately below the selected driving piezo element 140, and the X-direction wiring 111, A voltage is applied between the previously selected Y-direction wiring 112. As a result, the polarization piezo element 120 immediately below the deformed drive piezo element 140 is polarized, and the deformation of the drive piezo element 140 can be maintained.
As described above, the first control unit 210 of the control unit 10 freely switches each of the first group of display areas 1a between the high reflectivity state and the low reflectivity state by the selection unit 11a. be able to.

  As described above, the control unit 10 once resets the reflectivity of all the display regions 1a to the initial state when forming interference fringes in the band-like region 1b of the first group or the second group. May be. In this operation, the selection unit 11a or the selection unit 11b sequentially selects the X-direction wiring 111 and the Y-direction wiring 112 connected to the polarization piezo element 120 corresponding to the display area 1a of the group to be processed. The electric charge accumulated in the polarization piezo element 120 may be discharged through the Y-direction wiring 112. If this operation is performed for all the display areas 1a constituting the target group, the reflectance of the display area 1a of the group returns to the initial state.

For example, the selection units 11a and 11b may have a function of simultaneously selecting all the X-direction wirings 111 and the Y-direction wirings 112, respectively. In this case, if all the X-direction wirings 111 and the Y-direction wirings 112 are selected and grounded on the side connected to the target group among the selection units 11a and 11b, all the display areas 1a of the group are supported. The polarization of the polarizing piezo element 120 is eliminated. In this configuration, many display areas 1a can be returned to the initial state easily and at high speed.
By performing this operation, in the operation of adjusting the reflectance of each display region 1a to form interference fringes, it is not necessary to consider the state of the previous display region 1a, and the speed and efficiency can be improved. it can.

As described above, according to the video display apparatus 100 according to the embodiment to which the present invention is applied, the Fabry which is the same principle as the principle having the characteristics of the physical structure for accurately generating the light wave interference phenomenon. The display area 1a of the display sheet 1 having a function of reflecting light of a predetermined wavelength by the light interference effect due to Perot interference is divided into a plurality of groups, and an interference fringe is provided for each group in the band-like area 1b configured by the display area 1a. Since the reference light is emitted from the light source unit 2, different three-dimensional images can be projected one after another while switching a plurality of groups. After projecting a hologram by one group, another image is projected by another group. By projecting the hologram, it is possible to display the stereoscopic image by the hologram by sequentially changing the hologram.
In this case, by switching between the first group and the second group, it is possible to ensure a long time for forming the interference fringes in one group, so that it is easy to increase the resolution. Since the second group of interference fringes may be formed while the first group of strip-like regions 1b are irradiated with the reference light 22, even if the resolution is increased and it takes time to form the interference fringes, the interference fringes The situation that the formation of can not catch up does not occur. As a result, dense interference fringes can be formed with high resolution. Further, since the hologram can be switched in a short time, the hologram can be changed at high speed, and a smooth stereoscopic image can be displayed. In particular, since a hologram has a characteristic that an afterimage tends to remain, by projecting the next hologram while leaving an afterimage of the previously projected hologram, a stereoscopic image that changes more smoothly can be displayed and reproduced. Furthermore, it does not require a special mechanism for speeding up the formation of interference fringes, and can be easily realized with a simple configuration. In particular, since the video display device 100 uses the flexible thin display sheet 1, it is easy to secure the installation location. For example, the video display device 100 is erected on the floor surface as a wall-hanging type or a hanging type. There is an advantage that the installation space may be small.

In addition, the control unit 10 continuously performs an operation of forming interference fringes constituting one frame image using the display area 1a of one group while switching the target group. Each time an interference fringe is formed in the display area 1a, the light source unit 2 switches the group irradiated with the reference light, so that the projection of a smooth stereoscopic image can be performed by changing the hologram continuously and at high speed. And it is easy to increase the resolution.
Further, the display sheet 1 is configured in a rectangular shape. In the rectangular display sheet 1, the plurality of display areas 1a are divided into a plurality of band-like areas 1b arranged along one side of the display sheet 1, and each group includes a plurality of band-like areas. 1b, and the band-like region 1b has a configuration in which the band-like regions 1b constituting different groups are arranged adjacent to each other. Therefore, in both the first group and the second group, the display sheet 1 is almost the same size. The interference fringes can be formed, so that the display area 1a of the display sheet 1 can be efficiently used to project a large hologram and a precise hologram. Moreover, since the size and position of the interference fringes hardly change when the group is switched, the change of the hologram when the group is switched can be made a slight change, and the stereoscopic image can be changed more smoothly. it can.

  Further, the amount of deformation of the driving piezo element 140 varies depending on the strength of the electric field applied to the driving piezo element 140. Therefore, the amount of deformation of the driving piezo element 140 is adjusted by adjusting the electric field applied to the driving piezo element 140 and the voltage applied to the polarization piezo element 120, and the light reflected by the dielectric mirror 142 is adjusted. The reflectivity or the reflection and absorption by the dielectric mirror 142 can be arbitrarily changed. That is, gradation expression can be realized by changing the reflectance in each display region 1a in a plurality of stages.

  Since the display sheet 1 can hold the deformation of the driving piezo element 140 by the electric charge accumulated in the polarization piezo element 120, the amount of power required to hold the display state is small, and the display sheet 1 can display for a long time without power supply. Can hold state. For this reason, the interference fringes formed by the control unit 10 can be held for a long time without being fed from the outside. In general, the deformation of the piezoelectric body is extremely rapid, and therefore the response time until the driving piezo element 140 in each display region 1a is deformed by the control of the control unit 10 is very short. For this reason, the process which forms an interference fringe in the display sheet 1 can also be performed at high speed in a short time. The display sheet 1 uses, for example, an apparatus configured in the same manner as an ink jet printer, and ejects a fluid material constituting the wiring portion 110, the polarization piezo element 120, the drive piezo element 140, and the like onto the base sheet 101. By doing so, it can be easily manufactured at low cost.

In addition, embodiment mentioned above shows the one aspect | mode which applied this invention, Comprising: This invention is not limited to the said embodiment.
In the said embodiment, although the structure which divided | segmented the display area 1a of the display sheet 1 into the 1st group and the 2nd group was demonstrated, this invention is not limited to this, It divides into 3 or more groups, It is of course possible to project holograms by forming interference fringes for each group. As the number of groups increases, it is possible to switch holograms in a time that is significantly shorter than the time required to form interference fringes, so that a stereoscopic image that changes more smoothly can be realized.
Moreover, in the said embodiment, although the structure which arranged the rectangular display area | region 1a in the matrix form on the rectangular display sheet 1 was mentioned as an example, it demonstrated and this invention is not limited to this, The display area | region 1a The shape of and the arrangement state of the display area 1a can be arbitrarily changed. For example, the hexagonal display areas 1a may be arranged so as to have a honeycomb-type planar filling structure, or the circular display areas 1a may be arranged. In this case, even if a gap is generated between the display areas 1a, there is no particular inconvenience as long as light does not leak from the gap to the front side of the display sheet 1.

  Further, in the above embodiment, the charge is accumulated by polarizing the polarization piezo element 120, but instead of the polarization piezo element 120, a charge accumulation element using a material other than a piezoelectric body is formed, An electric field may be generated around the driving piezo element 140 by the electric charge accumulated in the charge accumulating element. The display sheet 1 only needs to reflect light of a specific wavelength due to Fabry-Perot interference between the surface layer 150 and the dielectric mirror 142, and therefore corresponds to a dielectric instead of the dielectric mirror 142. You may provide a half mirror with the material which does not. Furthermore, the number and arrangement direction of the polarization piezo elements 120 and the drive piezo elements 140 in the display sheet 1 are arbitrary, and the hexagonal polarization piezo elements 120 and the drive piezo elements 140 may be arranged in a honeycomb shape. Alternatively, a circular polarization piezo element 120 and a drive piezo element 140 may be used. An insulating spacer may be provided between the polarization piezo elements 120 as in the case where the spacer 141 is provided between the adjacent drive piezo elements 140. The display color in the display sheet 1 is also arbitrary, and the display sheet 1 in a state where all the polarization piezo elements 120 are not polarized is white when the display unit 1 is not energized from the control unit 10. However, other colors may be used, and other details may be arbitrarily changed.

  DESCRIPTION OF SYMBOLS 1 ... Display sheet (sheet | seat), 1a ... Display area, 1b ... Strip | belt-shaped area | region (band-shaped area | region), 2 ... Light source unit I (light source), 10 ... Control part, 11 ... Selection circuit, 11a, 11b ... Selection part, 100 DESCRIPTION OF SYMBOLS Image display apparatus (display apparatus) 140 ... Drive piezo element (piezoelectric body) 142 ... Dielectric mirror (reflection layer) 143 ... Oxide film 150 ... Surface layer (reflection layer)

Claims (4)

A plurality of display areas for forming interference fringes are provided side by side on a flexible sheet,
Each display region has a reflection layer that reflects light of a predetermined wavelength of incident light due to a light interference effect of Fabry-Perot interference of light incident from outside, and a reflection layer that is deformed according to the surrounding electric field and reflected by the reflection layer. A piezoelectric body that changes the rate, and
A selection unit for selecting the piezoelectric body corresponding to the specific display area;
A control unit that causes the selection unit to select a specific piezoelectric body and deforms the piezoelectric body by applying an electric field, thereby forming interference fringes in the display region due to a difference in reflectance in the reflective layer;
A light source for irradiating reference light to the interference fringes formed in the display area,
The plurality of display areas are divided into a plurality of groups, and the control unit forms interference fringes constituting one image using the display areas of one group, and the light sources are arranged in the display areas for each group. Irradiating the formed interference fringes with reference light;
A display device. By the control unit, the operation of forming interference fringes constituting one image using the display area of one group is continuously executed while switching the target group,
Each time an interference fringe is formed in the display area of each group by the control unit, switching the group irradiated with the reference light by the light source,
The display device according to claim 1. The sheet is configured by a rectangle, and in the rectangular sheet, the plurality of display areas are divided into a plurality of band-shaped areas arranged along one side of the sheet, and each group is configured by a plurality of band-shaped areas,
The band-shaped region is arranged so that regions constituting different groups are adjacent to each other,
The display device according to claim 1 or 2. A plurality of display areas for forming interference fringes are provided side by side on a flexible sheet,
Each display region has a reflection layer that reflects light of a predetermined wavelength of incident light due to a light interference effect of Fabry-Perot interference of light incident from outside, and a reflection layer that is deformed according to the surrounding electric field and reflected by the reflection layer. Controlling a display device comprising a piezoelectric body that changes the rate,
By selecting the piezoelectric body corresponding to the specific display area and applying an electric field to the selected specific piezoelectric body to deform it, an interference fringe is formed in the display area due to a difference in reflectance in the reflective layer. ,
The plurality of display areas are divided into a plurality of groups, and interference fringes constituting one image are formed using the display areas of one group, and reference light from the light source is formed on the interference fringes formed in the display areas for each group. Irradiating,
A display control method characterized by the above.

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