JP7308122B2 - image display device - Google Patents

Description

The present invention relates to an image display device capable of displaying stereoscopic images and two-dimensional images.

Conventionally, various stereoscopic image display techniques have been proposed, including a twin-lens stereoscopic system using 3D glasses. In particular, the integral method does not require special glasses and can reproduce natural 3D images with horizontal and vertical parallax, so it is expected to be applied to various 3D applications in the future. Generally, in the integral method, a lens array composed of element lenses is installed in front of the display panel, or a point light source array composed of point light sources is installed in the back of the display panel. By displaying the elemental images at the corresponding positions of the display panel, the observer can visually recognize the stereoscopic image.
In the future, in order to display a variety of video content, it will be possible to display high-definition two-dimensional images (hereinafter referred to as 2D display) in addition to integral stereoscopic image display (hereinafter referred to as 3D display). is desirable.

Against this background, a method for switching between 3D display and 2D display has been proposed in an integral method using a point light source array (see Non-Patent Documents 1 and 2 and Patent Document 1).
The method described in Non-Patent Document 1 switches between 3D display and 2D display by using a liquid crystal film (PDLC: Polymer Dispersed Liquid Crystal) that transmits or diffuses light from a parallel light source by voltage control.
The method described in Non-Patent Document 2 uses an LED array with a two-layer structure and a diffusion plate provided with openings, and the LED light passing through the openings and the LED light diffused by the diffusion plate are transferred to the lens array. 3D display and 2D display are switched by switching the emitted light.
The method described in Patent Document 1 uses a transmission/diffusion plate provided with a region for transmitting or diffusing light for each LED, and by switching the light emitting region of each LED of the LED array, 3D display and 2D display for each region Switch between display and

JP 2019-086710 A

Jae-Hyeung Park, Hak-Rin Kim, Yunhee Kim, Joohwan Kim, Jisoo Hong, Sin-Doo Lee, and Byoungho Lee, “Depth-enhanced three-dimensional-two-dimensional convertible display based on modified integral imaging”, OPTICS LETTERS , vol.29, No.23, pp.2734-2736, December 1, 2004. Seong-Woo Cho, Jae-Hyeung Park, Yunhee Kim, Heejin Choi, Joohwan Kim, and Byoungho Lee, “Convertible two-dimensional-three-dimensional display using an LED array based on modified integral imaging”, OPTICS LETTERS, Vol.31 , No.19, pp.2852-2854, October 1, 2006.

The method described in Non-Patent Document 1 can only control transmission/diffuse of the entire input light by PDLC. Also, in the method described in Non-Patent Document 2, light from one LED is projected onto a plurality of lenses of a lens array.
Therefore, the methods described in Non-Patent Documents 1 and 2 can only switch between 3D display and 2D display over the entire screen.

On the other hand, the method described in Patent Literature 1 can divide the 3D display area and the 2D display area and display a mixture of a stereoscopic image and a two-dimensional image on the screen.
However, these conventional methods require special light sources such as parallel light sources and LED arrays as backlights, and are limited to transmissive spatial light modulators (liquid crystal panels, etc.) as display panels.
Therefore, there has been a demand for a method of switching between 3D display and 2D display using a more general direct-view display panel.

The present invention has been made in view of such problems and demands, and uses a direct-view display panel to switch between 3D display and 2D display, or to display images in a mixed manner. An object is to provide a display device.

In order to solve the above-mentioned problems, an image display device according to the present invention is an image display device that switches between or displays a stereoscopic image and a two-dimensional image, comprising: a display panel; a polarizing element; The configuration includes a switching element, a 3D/2D switching section, and a control section.

In such a configuration, the image display device uses the display panel to display an elemental image group composed of integral type elemental images or a two-dimensional image on the entire screen or by dividing the area.
Then, the image display device uses a polarizing element arranged to face the display panel to pass only a specific polarized light, for example, horizontally polarized light, out of the light displayed by the display panel.
Then, in the image display device, the polarization switching element switches the light that has passed through the polarization element between one polarization state and the other polarization state for each region. The polarization switching element is controlled by the controller so that the light corresponding to the display area of the elemental image is switched to the light of one polarization state, and the light corresponding to the display area of the two-dimensional image is switched to the light of the other polarization state. controlled separately. For example, the polarization switching element transmits the light corresponding to the elemental image as it is as horizontally polarized light, and switches the light corresponding to the two-dimensional image to the light of the vertical image.
As a result, the polarization switching element converts the light into different polarization states in the area where the elemental image is displayed and the area where the two-dimensional image is displayed on the display panel.

Then, the image display device has a function of condensing the light of one polarization state corresponding to the display area of the elemental image by the 3D/2D switching section as an integral type element lens by diffraction for each elemental image. , the light of the other polarization state corresponding to the display area of the two-dimensional image is passed through without being condensed. Whether or not to condense light according to the polarization state can be realized by, for example, combining a polarized diffraction lens and a condensing lens.
Thereby, the 3D/2D switching section functions as an integral lens element in the area where the element image is displayed, and the observer can visually recognize the stereoscopic image. In addition, the 3D/2D switching section functions as a transparent member that allows light to pass through in a region where a two-dimensional image is displayed, so that the observer can visually recognize the two-dimensional image.

ADVANTAGE OF THE INVENTION This invention has the outstanding effect shown below.
According to the present invention, a stereoscopic image and a two-dimensional image can be switched or displayed by dividing into regions using a general direct-view display panel without requiring a special light source as a backlight. be able to.
Accordingly, the present invention can display various contents on one device.

1 is a perspective view of the appearance of an image display device according to an embodiment of the present invention for explaining the outline of the image display device; FIG. 1 is a top view showing the structure of a display section of an image display device according to an embodiment of the present invention; FIG. FIG. 4 is an explanatory diagram for explaining polarization switching of light emitted from a display panel; It is a front view which shows the structure of a 3D/2D switching lens array. FIG. 4 is an explanatory diagram for explaining the action of the polarized diffraction lens, in which (a) shows a state in which horizontally polarized light is incident, and (b) is a diagram showing a state in which vertically polarized light is incident. FIG. 4 is an explanatory diagram for explaining the characteristics of a polarizing diffraction lens; FIG. 4 is an explanatory diagram for explaining the action of a lens that combines a polarized diffraction lens and a condenser lens, in which (a) shows a state in which horizontally polarized light is incident, and (b) is a state in which vertically polarized light is incident. It is a figure which shows. It is a block diagram showing the configuration of the control unit of the image display device according to the embodiment of the present invention. FIG. 4 is an explanatory diagram for explaining the operation of 3D display in the image display device according to the embodiment of the present invention; FIG. 4 is an explanatory diagram for explaining the operation of 2D display in the image display device according to the embodiment of the present invention; FIG. 4 is an explanatory diagram for explaining an operation of mixing 3D display and 2D display in the image display device according to the embodiment of the present invention; FIG. 11 is a configuration diagram showing another configuration example of a 3D/2D switching lens array; FIG. 10 is an explanatory diagram for explaining the action of the 3D/2D switching lens array of another configuration example, in which (a) shows a state in which horizontally polarized light is incident, and (b) shows a state in which vertically polarized light is incident; FIG. 4 is a diagram showing;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Overview of image display device]
An overview of an image display device 1 according to an embodiment of the present invention will be described with reference to FIG.
The image display device 1 switches and displays a stereoscopic image _I3D and a two-dimensional image _I2D . As shown in FIG. 1 , the image display device 1 includes a display section 10 and a control section 20 .

The display unit 10 displays images (stereoscopic image I _3D , two-dimensional image I _2D ). For the stereoscopic image _I3D , the display unit 10 displays a group of element images of the integral method so that the observer M can visually recognize the stereoscopic image _I3D . On the other hand, for the two-dimensional image _I2D , the display unit 10 displays the two-dimensional image itself on the screen.
The control unit 20 controls switching between display of the stereoscopic image _I3D and display of the two-dimensional image _I2D on the display unit 10 .

Note that the image display device 1 can switch between the stereoscopic image _I3D and the two-dimensional image _I2D on the entire screen, and the stereoscopic image _I3D and the two-dimensional image _I2D can be mixed in different areas of the screen. It is also possible to let
The configuration of the image display device 1 will be described in detail below.

[Configuration of image display device]
First, the configuration of the display unit 10 of the image display device 1 will be described with reference to FIG. 2 (see also FIG. 1 as necessary). FIG. 2 is a top view showing the configuration of the display unit 10, which is seen through the area indicated by symbol A of the image display device 1 shown in FIG.
As shown in FIG. 2, the display unit 10 includes a display panel 11, a polarization element 12, a polarization switching element 13, and a 3D/2D switching lens array .

The display panel 11 displays an elemental image group composed of integral type elemental images or a two-dimensional image on the whole screen or by dividing the area.
The display panel 11 is a general direct-view display such as a liquid crystal display or an organic EL (Electronic Luminescent) display.
This display panel 11 displays a group of elemental images of the integral method when the observer M visually recognizes the stereoscopic image _I3D . Further, when the observer M visually recognizes the two-dimensional image _I2D , the display panel 11 displays the two-dimensional image _I2D itself. The image displayed by the display panel 11 may be a still image or a moving image in which a plurality of images are continuous.
The display panel 11 irradiates the polarizing element 12 with display light displaying an image.

The polarizing element 12 allows only specific polarized light among the randomly polarized display light emitted from the display panel 11 to pass therethrough. Here, the polarization element 12 is assumed to pass only horizontally polarized light.
The polarizing element 12 is arranged on the light emitting side of the display panel 11 so as to face the display panel 11 . The polarizing element 12 may be arranged with a predetermined gap (for example, about several millimeters) from the display panel 11, or may be arranged closely.
The light that has passed through the polarization element 12 is applied to the polarization switching element 13 .

The polarization switching element 13 switches the light that has passed through the polarization element 12 between one polarization state and the other polarization state for each region. For the polarization switching element 13, for example, a liquid crystal element such as a ferroelectric liquid crystal or an OCB (Optically Compensated Bend) liquid crystal having a high response speed can be used.
The polarization switching element 13 is arranged on the light exit side of the polarization element 12 . The polarization switching element 13 may be arranged with a predetermined gap (for example, about several millimeters) from the polarizing element 12, or may be arranged closely.
Here, under the control of the control unit 20, the polarization switching element 13 allows the horizontally polarized light (one polarization state) to pass through as it is, and converts the horizontally polarized light to the vertically polarized light (the other polarization state). Switch to and from the state that transforms into light. The unit of the polarization switching region of the polarization switching element 13 is each irradiation range corresponding to the polarization diffraction lens L1 of the polarization diffraction lens array 141, which will be described later.
The light (horizontally polarized or vertically polarized) that has passed through the polarization switching element 13 is applied to the polarization diffraction lens array 141 of the 3D/2D switching lens array 14 .

Polarization switching of light by the polarizing element 12 and the polarization switching element 13 described above will be described with reference to FIG.
As shown in FIG. 3 , the polarizing element 12 passes only horizontally polarized light out of the randomly polarized light emitted from the display panel 11 .
The polarization switching element 13 allows the horizontally polarized light that has passed through the polarizing element 12 to pass through as it is, or converts the polarization state to vertically polarized light. Or switch partially.
As a result, the polarization switching element 13 can irradiate the polarization diffraction lens array 141 with specific polarized light for each polarization diffraction lens L1.
Returning to FIG. 2, the description of the configuration of the display unit 10 is continued.

The 3D/2D switching lens array (3D/2D switching unit) 14 converts the light of one polarization state (here, horizontal polarization) corresponding to the display area of the element image into an integral type element by diffraction for each element image. It has a function of condensing light as a lens, and passes the light of the other polarization state (here, vertically polarized light) corresponding to the display area of the two-dimensional image without condensing.
The 3D/2D switching lens array 14 includes a polarization diffraction lens array 141 and a condenser lens array 142, as shown in FIG.
As shown in FIG. 4, the 3D/2D switching lens array 14 includes a polarization diffraction lens array 141 and a condenser lens array 142, and a polarization diffraction lens L1 and a condenser lens L2 that constitute the respective lens arrays. Place them so that they face each other.

The polarization diffraction lens array 141 diffracts incident light according to the polarization state of the light emitted from the polarization switching element 13 .
The polarization diffraction lens array 141 is arranged on the light exit side of the polarization switching element 13 . The polarization diffraction lens array 141 may be arranged with a predetermined gap (for example, about several millimeters) from the polarization switching element 13, or may be arranged closely.
However, the polarizing diffraction lens array 141 is spaced apart from the display surface of the display panel 11 by half the focal length of a combined lens of a polarizing diffraction lens L1 and a condenser lens L2 of the condenser lens array 142, which will be described later. do. The reason for this separation distance will be described later with reference to FIG.
The polarized diffraction lens array 141 is configured by arranging polarized diffraction lenses L1 on a two-dimensional plane as shown in FIG. 4 when viewed from the front. The lens pitch of the polarizing diffraction lens L1 is the same as the pitch of the element images of the element image group displayed on the display panel 11 .

The polarized diffraction lens L1 functions as a lens (convex lens or concave lens) that diffracts incident light into ±1st-order light according to two different polarization states and has a positive or negative focal length with respect to the traveling direction of light. It is.
Here, the polarization diffraction lens L1 has a positive focal length (f) when horizontally polarized light is incident on the plane of incidence, as shown in FIG. It functions as a lens (convex lens).
In addition, when vertically polarized light is incident on the plane of incidence, the polarizing diffraction lens L1 has a negative focal length (-f) with the traveling direction of the light being positive, as shown in FIG. 5(b). It functions as a lens (concave lens).

As shown in FIG. 6, the polarizing diffraction lens L1 has a diffraction portion Ld that diffracts light and a non-diffraction portion Lt that does not diffract light according to the shape of the facing condenser lens L2.
The diffraction part Ld is a lens that diffracts light as described with reference to FIG. The focal length of the polarizing diffraction lens L1 can be determined by the pitch of the diffraction grating formed concentrically in the diffraction section Ld.
The non-diffracting portion Lt is a region formed of a transmissive member that transmits light without diffracting it. The non-diffracting portion Lt can be made of general glass or the like.

In addition, when using the same shape as the polarizing diffraction lens L1 as the condensing lens L2, it is not necessary to provide the non-diffraction part Lt in the polarizing diffraction lens L1.
Further, when a non-diffraction portion Lt corresponding to the shape of the condensing lens L2 is provided as the polarizing diffraction lens L1, each element image of the element image group displayed on the display panel 11 has a black area corresponding to the non-diffraction portion Lt. to be displayed. This makes it possible to suppress unnecessary light emission when displaying a stereoscopic image.
The polarization diffraction lens array 141 irradiates the condenser lens array 142 with the light diffracted according to the polarization state.

In this way, lenses that diffract light according to the polarization state are disclosed in patent documents such as JP-A-2006-106726, JP-A-2008-233539, JP-A-2016-136165, and the following references. can be realized by a known phase hologram technique described in .
(References) Jihwan Kim, Yanming Li, Matthew N. Miskiewicz, Chulwoo Oh, Michael W. Kudenov, and Michael J. Escuti, “Fabrication of ideal geometric-phase holograms with arbitrary wavefronts”, Optical Society of America, optica, vol. .2, No.11, pp.958-964, November 2015.

The condenser lens array 142 changes the traveling direction of the light emitted from the polarized diffraction lens array 141 .
The condenser lens array 142 is arranged on the light exit side of the polarized diffraction lens array 141 . It is preferable that the condenser lens array 142 is arranged in close contact with the polarization diffraction lens array 141 .
As shown in FIG. 4, the condenser lens array 142 is configured by arranging condenser lenses L2 on a two-dimensional plane. The lens pitch of this condenser lens L2 is the same as that of the polarizing diffraction lens L1.
The condenser lens L2 functions as a lens (convex lens) having a positive focal length with respect to the traveling direction of light. The focal length of this condensing lens L2 is set to the same focal length (f) as that of the polarizing diffraction lens L1.

As a result, the 3D/2D switching lens array 14 functions as a positive focal length (f) as shown in FIG. 7A when horizontally polarized light is incident on the polarization diffraction lens L1. L1 and the condensing lens L2, which similarly functions as a positive focal length (f), function as a combined lens with a combined focal length (f/2) of two convex lenses.
Therefore, by arranging the polarizing diffraction lens L1 and the condensing lens L2 from the display surface of the display panel 11 by half the focal length of the composite lens, the polarizing diffraction lens L1 and the condensing lens L2 can It functions as an element lens (focal length is f/2) in the integral system. That is, the 3D/2D switching lens array 14 functions as an element lens array in the integral system.
Thereby, the polarizing diffraction lens L1 and the condenser lens L2 allow the observer M to visually recognize the group of elemental images displayed on the display panel 11 as a stereoscopic image _I3D .

On the other hand, when vertically polarized light is incident on the polarizing diffraction lens L1, as shown in FIG. ) functions as a non-diffractive member (transmissive member) by canceling out the light-collecting action.
Therefore, the polarizing diffraction lens L1 and the condensing lens L2 can transmit the two-dimensional image _I2D displayed on the display panel 11 without condensing it, so that the observer M can visually recognize the two-dimensional image I2D.

Next, the configuration of the control unit 20 will be described with reference to FIG.
As shown in FIG. 8 , the control unit 20 includes 3D/2D image input means 21 , 3D/2D image display means 22 , display switching instruction input means 23 and polarization switching control means 24 .

The 3D/2D image input means 21 inputs a group of integral image elements or a two-dimensional image. The 3D/2D image input means 21 outputs the inputted elemental image group or two-dimensional image to the 3D/2D image display means 22 .
The 3D/2D image input means 21 inputs images via an external disk device, communication line, etc. (not shown).
The 3D/2D image input means 21 inputs either an elemental image group or a two-dimensional image, or inputs an image in which an elemental image group and a two-dimensional image are mixed by dividing the display area. There is.

The 3D/2D image display means 22 inputs the image (element image group, two-dimensional image) input by the 3D/2D image input means 21 and displays it on the display panel 11 . The 3D/2D image display means 22 is connected to the display panel 11 via a signal line (not shown).

The display switching instruction input unit 23 inputs an instruction to switch the display method between 3D display and 2D display via a switch (not shown) or a communication line.
Specifically, the switching instruction is a signal that instructs whether or not to switch the polarization state of the polarization switching element 13 for each area of the polarization diffraction lens L1. This switching instruction corresponds to an image input to the 3D/2D image input means 21 in advance, and is an instruction indicating different polarization states between the image area of the elemental image group and the image area of the two-dimensional image.
Here, the switching instruction is an instruction indicating that the polarization state of the polarization switching element 13 is not switched when performing 3D display (display of a group of elemental images), and when performing 2D display (display of a two-dimensional image), the polarization state is not switched. This is an instruction to switch the polarization state of the switching element 13 .
The display switching instruction input means 23 outputs the input switching instruction to the polarization switching control means 24 .

The polarization switching control means 24 switches the polarization state of the polarization switching element 13 for each irradiation range corresponding to the polarization diffraction lens L1 according to the switching instruction input by the display switching instruction input means 23 .
The polarization switching control means 24 is connected to the polarization switching element 13 via a signal line (not shown), and switches the polarization state by voltage control.
Here, when the polarization state of the light corresponding to the polarization diffraction lens L1 is not switched by the switching instruction, the polarization switching control means 24 applies a voltage to the polarization switching element 13 corresponding to the irradiation range of the polarization diffraction lens L1. shall not be performed.
When the polarization state of the light corresponding to the polarization diffraction lens L1 is switched by the switching instruction, the polarization switching control means 24 applies a voltage to the polarization switching element 13 corresponding to the irradiation range of the polarization diffraction lens L1.

By configuring the image display device 1 as described above, the image display device 1 switches the display light displayed by the direct-view display panel 11 to horizontally polarized light or vertically polarized light, and switches the 3D/2D switching lens array 14. 3D display and 2D display can be switched over the entire screen or partially.

[Operation of image display device]
Next, referring to FIGS. 9 to 11 (see FIGS. 1, 2, and 8 as appropriate), 3D display, 2D display, and 3D/2D mixed display are performed in the image display device 1 according to the embodiment of the present invention. Operation will be explained.

(3D display)
First, with reference to FIG. 9, the operation of the image display device 1 for 3D display will be described.
The image display device 1 inputs an instruction indicating that the polarization state of the polarization switching element 13 is not switched as a switching instruction for 3D display by the display switching instruction input means 23 of the control unit 20 .
Then, the image display device 1 voltage-controls the polarization switching element 13 by the polarization switching control means 24 so that the horizontally polarized light that has passed through the polarization element 12 is allowed to pass through as it is. Specifically, the polarization switching control means 24 does not apply voltage to the polarization switching element 13, or stops applying voltage if it is in the applied state.
As a result, the horizontally polarized light incident on the polarization switching element 13 passes through the polarization switching element 13 as horizontally polarized light.

After that, the image display device 1 receives an elemental image group composed of the elemental image e by the 3D/2D image input means 21 of the control section 20, and displays the elemental image group on the display panel by the 3D/2D image display means 22. 11.
Then, the randomly polarized display light of the display panel 11 is changed to horizontally polarized light by the polarizing element 12 and passes through the polarization switching element 13 .
By irradiating the 3D/2D switching lens array 14 with horizontally polarized light that has passed through the polarization switching element 13, the 3D/2D switching lens array 14 functions as an integral element lens array.
The observer M can visually recognize the stereoscopic image I _3D by observing the display panel 11 through the 3D/2D switching lens array 14 .

(2D display)
Next, with reference to FIG. 10, the operation of performing 2D display of the image display device 1 will be described.
The image display device 1 inputs an instruction to switch the polarization state of the polarization switching element 13 as a switching instruction to perform 2D display by the display switching instruction input unit 23 of the control unit 20 .
Then, the image display device 1 voltage-controls the polarization switching element 13 by the polarization switching control means 24 so that the horizontally polarized light that has passed through the polarization element 12 is converted into the vertically polarized light. Specifically, the polarization switching control means 24 applies a voltage to the polarization switching element 13 .
As a result, the horizontally polarized light incident on the polarization switching element 13 is converted into vertically polarized light and emitted from the polarization switching element 13 .

After that, the image display device 1 inputs the two-dimensional image _I2D through the 3D/2D image input means 21 of the control unit 20, and displays the two-dimensional image _I2D on the display panel 11 through the 3D/2D image display means 22. do.
Then, the randomly polarized display light of the display panel 11 becomes horizontally polarized light by the polarizing element 12 and is converted into vertically polarized light by the polarization switching element 13 .
By irradiating the 3D/2D switching lens array 14 with the vertically polarized light converted by the polarization switching element 13, the 3D/2D switching lens array 14 functions as a non-diffractive member (transmissive member).
The observer M can visually recognize the two-dimensional image _I2D by observing the display panel 11 through the 3D/2D switching lens array 14 .

(3D/2D mixed display)
Next, the operation of performing 3D/2D mixed display of the image display device 1 will be described with reference to FIG.
The image display device 1 uses the display switching instruction input means 23 of the control unit 20 to provide a switching instruction to perform mixed 3D/2D display, an instruction indicating that the polarization state of the polarization switching element 113 is not switched, or an instruction indicating that the polarization state of the polarization switching element 113 is not switched. is input for each region corresponding to the polarizing diffraction lens L1.
Here, the polarization switching element 13 corresponding to the polarizing diffraction lens L1 in the area for 3D display is instructed not to switch the polarization state, and the polarization switching element 13 corresponding to the polarizing diffraction lens L1 in the area for 2D display is instructed. indicates to switch the polarization state.

Then, the image display device 1 controls the voltage of the polarization switching element 13 by the polarization switching control means 24 for each region indicated by the switching instruction.
Specifically, the polarization switching control means 24 does not apply a voltage to a region of the polarization switching element 13 instructed not to switch the polarization state, and does not apply a voltage to the area of the polarization switching element 13 instructed not to switch the polarization state. A voltage is applied for the area.
As a result, the horizontally polarized light in the region for 3D display that has entered the polarization switching element 13 passes through the polarization switching element 13 as horizontally polarized light, and enters the polarization switching element 13 as horizontally polarized light in the region for 2D display. is converted into vertically polarized light and emitted from the polarization switching element 13 .

After that, the image display device 1 inputs an image in which a group of elemental images and a two-dimensional image are mixed by the 3D/2D image input means 21 of the control unit 20, and displays the image on the display panel by the 3D/2D image display means 22. 11.
Then, the randomly polarized display light corresponding to the 3D display area of the display panel 11 (the display area of the elemental image group composed of the elemental images e) is converted to horizontally polarized light by the polarizing element 12, and the polarization switching element. Pass 13.
By irradiating the 3D/2D switching lens array 14 with horizontally polarized light that has passed through the polarization switching element 13, the 3D/2D switching lens array 14 functions as an integral element lens array.

On the other hand, the randomly polarized display light corresponding to the 2D display area of the display panel 11 (the display area of the two-dimensional image _I2D ) becomes horizontally polarized light by the polarizing element 12, and becomes vertically polarized light by the polarization switching element 13. is converted into light of
By irradiating the 3D/2D switching lens array 14 with the vertically polarized light converted by the polarization switching element 13, the 3D/2D switching lens array 14 functions as a non-diffractive member (transmissive member).
By observing the display panel 11 through the 3D/2D switching lens array 14, the observer M can visually recognize the stereoscopic image I _3D in the area where the elemental image e is displayed. In the area where the _I2D is displayed, the two-dimensional image _I2D can be visually recognized as it is.

[Modification]
Although the configuration and operation of the image display device 1 according to the embodiment of the present invention have been described above, the present invention is not limited to this embodiment.

(Modification of 3D/2D switching lens array)
The 3D/2D switching lens array 14 may have the configuration of the 3D/2D switching lens array 14B shown in FIG.
The 3D/2D switching lens array 14B, like the 3D/2D switching lens array 14, is a lens for displaying a stereoscopic image or a two-dimensional image, depending on the polarization state of light emitted from the polarization switching element 13. It functions as a lens for displaying
As shown in FIG. 12, the 3D/2D switching lens array 14B includes a first polarized diffraction lens array 141, a λ/4 wavelength plate 143, a polarizing element 144, and a second polarized diffraction lens array 141B. Prepare.
The first polarization diffraction lens array 141 has the same configuration as the 3D/2D switching lens array 14 described with reference to FIG. 2, so description thereof is omitted.

The λ/4 wavelength plate 143 is arranged on the light exit side of the polarizing diffraction lens array 141, and produces a 1/4 wavelength phase difference with respect to the light (linearly polarized light) irradiated from the polarizing diffraction lens array 141. , which converts the light into circularly polarized light. Here, the λ/4 wavelength plate 143 is arranged so as to be inclined by 45° with respect to the optical axis so that linearly polarized light is incident thereon.
Here, the λ/4 wavelength plate 143 converts incident horizontal polarized light, which is linearly polarized light, into right-handed circularly polarized light. If the incident linearly polarized light is vertically polarized light, the λ/4 wavelength plate 143 converts it into left-handed circularly polarized light.
The λ/4 wavelength plate 143 may be arranged with a predetermined gap (for example, about several millimeters) from the polarizing diffraction lens array 141, or may be arranged closely.
The circularly polarized light converted by the λ/4 wavelength plate 143 is applied to the polarization element 144 .

The polarizing element (second polarizing element) 144 is arranged on the light output side of the λ/4 wavelength plate 143, and among the circularly polarized light emitted from the λ/4 wavelength plate 143, only the light of specific polarization to pass through. Here, the polarizing element 144 uses a linear polarizing element that allows only horizontal polarized light to pass through.
The polarizing element 144 may be arranged with a predetermined gap (for example, about several millimeters) from the λ/4 wavelength plate 143, or may be arranged closely.
The light that has passed through the polarizing element 144 is applied to the polarized diffraction lens array 141B.

The second polarized diffraction lens array 141B is arranged on the light exit side of the polarizing element 144 and diffracts the incident light according to the polarization state of the light emitted from the polarizing element 144 .
The polarizing diffraction lens array 141B may be arranged with a predetermined gap (for example, about several millimeters) from the polarizing element 144, or may be arranged closely.
Like the polarized diffraction lens array 141, the polarized diffraction lens array 141B is configured by arranging the polarized diffraction lenses L1B on a two-dimensional plane.

The polarized diffraction lens L1B functions as a lens (convex lens or concave lens) that diffracts incident light into ±1st-order light according to two different polarization states and has a positive or negative focal length with respect to the traveling direction of light. It is.
However, in this case, the polarizing element 144 functions as a lens (convex lens) having a positive focal length in order to pass only light of specific polarization (horizontal polarization).
The focal length of the polarized diffraction lens L1B of the polarized diffraction lens array 141B is the same as that of the polarized diffraction lens L1 of the polarized diffraction lens array 141B. In other words, the polarization diffraction lens array 141B having the same configuration as the polarization diffraction lens array 141 can be used.

Here, with reference to FIG. 13, changes in the polarization state of incident light in the 3D/2D switching lens array 14B of FIG. 12 will be described.
As shown in FIG. 13A, when horizontally polarized light is applied to the polarization diffraction lens array 141 as incident light, the polarization diffraction lens L1 of the polarization diffraction lens array 141 functions as a positive focal length (f). Then, the λ/4 wavelength plate 143 is irradiated with the incident light in the horizontally polarized state.
Then, the λ/4 wavelength plate 143 changes the irradiated horizontally polarized light into right-handed circularly polarized light, and irradiates the polarizing element 144 with the right-handed circularly polarized light.
Further, the polarizing element 144 passes only the horizontally polarized light among the irradiated right-handed circularly polarized light, and irradiates the polarized diffraction lens array 141B with the horizontally polarized light.
The polarization diffraction lens array 141B is irradiated with horizontally polarized light, and the polarization diffraction lens L1B of the polarization diffraction lens array 141B functions as a positive focal length (f).
Thereby, the 3D/2D switching lens array 14B functions as a positive focal length (f) similarly to the polarization diffraction lens L1 which functions as a positive focal length (f) when irradiated with horizontally polarized light. Together with the polarizing diffraction lens L1B, it functions as a composite lens with a focal length (f/2).

Further, as shown in FIG. 13(b), when vertically polarized light is applied to the polarization diffraction lens array 141 as incident light, the polarization diffraction lens L1 of the polarization diffraction lens array 141 has a negative focal length (-f ), and irradiates the λ/4 wavelength plate 143 with the incident light in the form of vertically polarized light.
Then, the λ/4 wavelength plate 143 changes the irradiated vertically polarized light into left-handed circularly polarized light, and irradiates the polarizing element 144 with the light.
Further, the polarizing element 144 passes only the horizontally polarized light among the irradiated left-handed circularly polarized light, and irradiates the polarized diffraction lens array 141B with the horizontally polarized light.
The polarization diffraction lens array 141B is irradiated with horizontally polarized light, and the polarization diffraction lens L1B of the polarization diffraction lens array 141B functions as a positive focal length (f).
Thereby, when the 3D/2D switching lens array 14B is irradiated with vertically polarized light, the polarization diffraction lens L1 functions as a negative focal length (-f), and the polarized light lens L1 functions as a positive focal length (f). The diffractive lens L1B functions as a non-diffractive member by canceling out the focusing action. In addition, since the 3D/2D switching lens array 14B overlaps the polarizing diffraction lenses L1 and L1B so as to cancel out the focal length, the wavelength dependence of the diffraction angle is also canceled, and a good two-dimensional image without chromatic dispersion is displayed. be able to.
Thus, the 3D/2D switchable lens array 14B has a configuration equivalent to that of the 3D/2D switchable lens array 14 .

By configuring the 3D/2D switching lens array 14B as described above, it is possible to use the polarization diffraction lens arrays 141 and 141B having the same configuration, and to minimize errors in lens pitch, focal length, and the like. . Further, the λ/4 wavelength plate 143, the polarizing element 144, and the polarizing diffraction lens array 141B can be molded thinner than the convex lens that is the condenser lens array 142, so that the overall device can be made thinner.

(Modified example of polarization state)
Here, the polarization state of the light applied to the 3D/2D switching lens arrays 14 and 14B is set to horizontal polarization in the 3D display area and vertical polarization in the 2D display area. However, this polarization state may be reversed.
In that case, the polarization switching control means 24 reverses switching between horizontal polarization and horizontal polarization in the polarization switching element 13 . Further, as the polarizing diffraction lens L1 of the polarizing diffraction lens array 141, a lens that functions as a lens having a negative focal length with respect to horizontally polarized light and as a lens having a positive focal length with respect to vertically polarized light is used. You can use it.

(Modified example of condenser lens array)
Here, the light entrance/exit surface of the polarizing diffraction lens array 141 is rectangular, and the polarizing diffraction lens L1 and the condensing lens L2 are arranged in a square arrangement, but the arrangement is not limited to this. For example, the polarizing diffraction lens array 141 and the condenser lens array 142 may be configured in a delta arrangement (bales stacked). Further, for example, the light exit surface of the polarizing diffraction lens array 141 may be hexagonal, and the polarizing diffraction lens array 141 and the condenser lens array 142 may be configured in a honeycomb structure.

Also, although the condenser lens array 142 constituting the condenser lens array 142 is circular here, it may have the same shape as the light exit surface of the polarization diffraction lens array 141 (rectangular shape, etc.).
Further, although the example in which the condenser lens array 142 is configured by a biconvex lens has been described here, it may be a planoconvex lens.

Further, although the condensing lens array 142 is arranged on the light exit side of the polarized diffraction lens array 141 here, it may be arranged closely on the light incident side of the polarized diffraction lens array 141 . When the condenser lens array 142 is arranged on the light exit side of the polarized diffraction lens array 141, the diffraction grooves of the polarized diffraction lens L1 are arranged on the light exit side. When the condenser lens array 142 is arranged on the light incident side of the polarization diffraction lens array 141, the diffraction grooves of the polarization diffraction lens L1 are set on the light incident side.

REFERENCE SIGNS LIST 1 image display device 10 display section 11 display panel 12 polarization element 13 polarization switching element 14 3D/2D switching lens array (3D/2D switching section)
14B 3D/2D switching lens array (3D/2D switching unit)
141 polarized diffraction lens array (first polarized diffraction lens array)
141B polarized diffraction lens array (second polarized diffraction lens array)
142 condenser lens array 143 λ/4 wavelength plate 144 polarizing element (second polarizing element)
L1 polarization diffraction lens L1B polarization diffraction lens Ld diffraction part Lt non-diffraction part L2 condenser lens 20 control part 21 3D/2D image input means 22 3D/2D image display means 23 display switching instruction input means 24 polarization switching control means

Claims (5)

An image display device that displays a stereoscopic image and a two-dimensional image by switching or mixing them,
an elemental image group composed of integral type elemental images, or a display panel for displaying the two-dimensional image on the entire screen or by dividing the area;
a polarizing element that is arranged to face the display panel and that transmits only light of specific polarization out of the light displayed by the display panel;
a polarization switching element that switches light that has passed through the polarization element between one polarization state and the other polarization state for each region;
With respect to the light in one polarization state corresponding to the display area of the element image, the integral lens has a function of condensing the light by diffraction for each element image, and corresponds to the display area of the two-dimensional image. a 3D/2D switching unit that passes the light in the other polarization state without condensing;
The polarization switching element is configured to switch the light corresponding to the display area of the element image to the light of the one polarization state, and the light corresponding to the display area of the two-dimensional image to the light of the other polarization state. a separately controlled control unit;
An image display device comprising: The 3D/2D switching unit is
a polarized diffraction lens array in which polarized diffraction lenses having a positive or negative focal length with respect to the traveling direction of light are arranged on a two-dimensional plane by diffraction according to the polarization state;
a condensing lens array in which condensing lenses are arranged on a two-dimensional plane in close contact with the polarizing diffraction lens array and have the same positive focal length as the polarizing diffraction lens array with respect to the traveling direction of light;
2. The image display device according to claim 1, comprising: The polarized diffraction lens has a diffraction portion that diffracts light in a region corresponding to the shape of the condenser lens when viewed from the front, and does not diffract light in a region other than the region corresponding to the shape of the condenser lens. 3. The image display device according to claim 2, wherein a non-diffracting portion is formed. 4. The condensing lens array according to claim 2 or 3, wherein the condensing lens array is arranged in close contact with the polarization diffraction lens array on either the light incident side or the light exit side of the polarization diffraction lens array. Image display device. The polarization state of the light switched by the polarization switching element is linearly polarized horizontally or vertically polarized light,
The 3D/2D switching unit is
a first polarized diffraction lens array in which polarized diffraction lenses having a positive or negative focal length with respect to the traveling direction of light are arranged on a two-dimensional plane by diffraction according to the polarization state;
a λ/4 wavelength plate for converting linearly polarized light emitted from the first polarized diffraction lens array into circularly polarized light;
a second polarizing element that passes only the one polarization state of the circularly polarized light converted by the λ/4 wavelength plate;
a two-dimensional planar polarizing diffraction lens having the same positive focal length as that of the polarizing diffractive lens constituting the first polarizing diffractive lens array by diffracting the light in one polarization state passing through the second polarizing element; a second polarized diffractive lens array arranged above;
2. The image display device according to claim 1, comprising:

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