WO2016117325A1

WO2016117325A1 - Display device

Info

Publication number: WO2016117325A1
Application number: PCT/JP2016/000230
Authority: WO
Inventors: 笠原　滋雄
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2015-01-20
Filing date: 2016-01-19
Publication date: 2016-07-28

Abstract

The objective of the present invention is to reduce the occurrence of moire in a display device formed by overlapping a plurality of display panels. The invention is provided with a first display panel having pixels formed in a region divided by means of a first stripe pattern, and a second display panel having pixels formed in a region divided by means of a second stripe pattern. The first display panel and second display panel are arranged so as to overlap, and the first stripe pattern is inclined at a prescribed angle relative to the second stripe pattern.

Description

Display device

This disclosure relates to a display device in which a plurality of display panels are stacked.

As a stereoscopic display method, a method of displaying a parallax image using a parallax barrier, a lenticular lens, or the like is known. However, in the case of a method of displaying a parallax image, there is a problem that visual fatigue is caused by a mismatch between binocular convergence and eye focus adjustment, and a device configuration is complicated.

Therefore, for example, in the display device described in Non-Patent Document 1, two transparent LCD (Liquid Crystal Display) panels are stacked one after the other at a predetermined interval, and the luminance ratio of the image displayed on each panel is changed. By doing so, a DFD (Depth Fused 3D) method has been proposed in which a stereoscopic image is displayed to an observer using an illusion phenomenon in which two images are merged. According to the DFD method, a stereoscopic display device can be realized with a simple device configuration with little eye strain.

A display device according to the present disclosure includes a first display panel in which pixels are formed in an area partitioned by a first stripe pattern, and a second display panel in which pixels are formed in an area partitioned by a second stripe pattern And comprising. The first display panel and the second display panel are arranged so as to overlap each other, and the first stripe pattern is inclined at a predetermined angle with respect to the second stripe pattern.

According to the present disclosure, it is possible to reduce the occurrence of moire in a display device in which a plurality of display panels are stacked.

FIG. 1 is a schematic diagram illustrating a schematic configuration of the display device according to the first embodiment. FIG. 2 is a block diagram for explaining an electrical configuration of the display device according to the first embodiment. FIG. 3 is a diagram showing a moire interference pattern with a two-panel configuration. FIG. 4 is a diagram illustrating a first example of a two-panel configuration in the display device according to the first embodiment. FIG. 5 is a diagram illustrating a second example of the two-panel configuration in the display device according to the first embodiment. FIG. 6 is a diagram illustrating a third example of the two-panel configuration in the display device according to the first embodiment. FIG. 7 is a diagram illustrating a fourth example of the two-panel configuration in the display device according to the first embodiment. FIG. 8 is a diagram illustrating a relationship between the panel rotation angle and the moire pitch of the display panel according to the first embodiment. FIG. 9A is a diagram illustrating an example in which the DFD method is applied to a liquid crystal display device. FIG. 9B is a diagram illustrating an example where the DFD method is applied to the liquid crystal display device. FIG. 10 is a diagram illustrating an example in which the DFD method is applied to a liquid crystal display device. FIG. 11A is a diagram illustrating an example in which the DFD method is applied to a liquid crystal display device. FIG. 11B is a diagram illustrating an example in which the DFD method is applied to the liquid crystal display device.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art. In addition, in order for those skilled in the art to provide a thorough understanding of the present disclosure, the accompanying drawings and the following description are provided, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
The first embodiment will be described below with reference to the accompanying drawings.

[1-1. Constitution〕
FIG. 1 is a schematic diagram illustrating a schematic configuration of the display device 100 according to the first embodiment. As shown in FIG. 1, the DFD display device 100 includes at least two display panels, a front panel 300 and a rear panel 400 that transmit visible light, and overlap each other when viewed from an observer with a predetermined gap. Is arranged. In FIG. 1, a liquid crystal display type display device 100 is described as an example of a DFD (depth fused 3D) type display device 100. However, the display device 100 is not limited to the liquid crystal display method, and may be an EL (Electro Luminescence) display method or an EC (Electrochromic) display method. Examples of display panels constituting liquid crystal display devices include twisted nematic liquid crystal displays, in-plane switching liquid crystal displays, vertical alignment liquid crystal displays, blue phase liquid crystal displays, ferroelectric liquid crystal displays, There are OCB (Optically Compensated Bend) type liquid crystal displays and guest-host type liquid crystal displays. The display device 100 may be configured by appropriately combining two display panels from among these.

As shown in FIG. 1, a display device 100 using a liquid crystal display system includes a front polarizing plate 200, a front panel 300, a back panel 400, a back polarizing plate 500, and a backlight 600 that are stacked in this order from the front side as viewed from the observer 50. Composed together. Note that the front polarizing plate 200 and the rear polarizing plate 500 are not necessary when the guest-host liquid crystal method, the EL method, or the EC method is used for the display device 100. Further, when the EL method is used for the display device 100, the backlight 600 is also unnecessary.

FIG. 2 is a block diagram for explaining an electrical configuration of the display device 100 according to the first embodiment. As shown in FIG. 2, the front panel 300, the back panel 400, and the backlight 600 constituting the display device 100 are electrically connected to the control circuit board 700.

The front panel 300 includes a liquid crystal display unit 310, a scanning line driving circuit 320, and a video line driving circuit 330. In the liquid crystal display unit 310, a plurality of scanning lines 321 extended from the scanning line driving circuit 320 and a plurality of video lines 331 extended from the video line driving circuit 330 are arranged.

The rear panel 400 includes a liquid crystal display unit 410, a scanning line driving circuit 420, and a video line driving circuit 430. The liquid crystal display unit 410 includes a plurality of scanning lines 421 extended from the scanning line driving circuit 420 and a plurality of video lines 431 extended from the video line driving circuit 430.

The backlight 600 includes, for example, an LED light source and an optical system such as a light guide plate that guides light emitted from the LED light source toward the rear panel 400 and the front panel 300. In order to make the light emitted from the LED light source uniform, a diffusion plate or the like may be provided. The arrangement of the LED light sources of the backlight 600 may be a direct type or an edge type.

The control circuit board 700 includes a backlight control circuit 710, an AC / DC (AC / DC) converter 720, a front image control circuit 730, and a back image control circuit 740. The control circuit board 700 supplies power and control signals to the front panel 300, the back panel 400, and the backlight 600.

The backlight control circuit 710 controls the backlight 600 based on an alternating current supplied from an AC (Alternating Current) power supply. Thereby, the backlight 600 can emit visible light toward the back panel 400 and the front panel 300 by causing the LED light source to emit light.

AC / DC converter 720 converts an alternating current supplied from an AC power source into a direct current. Then, the AC / DC converter 720 supplies the converted direct current to the front panel 300 and the back panel 400. Thereby, the front panel 300 and the back panel 400 can perform various operations.

The front image control circuit 730 generates a timing signal, a gradation voltage, a common voltage, and the like based on the acquired front image signal and supplies them to the front panel 300. In response to this supply, the front panel 300 drives the scanning line driving circuit 320 and the video line driving circuit 330 to operate the scanning line 321 and the video line 331. Accordingly, the front panel 300 can control the orientation of the liquid crystal molecules of the liquid crystal display unit 310 and display an image based on the light emitted from the backlight 600.

The rear image control circuit 740 generates a timing signal, a gradation voltage, a common voltage, and the like based on the acquired rear image signal and supplies them to the rear panel 400. In response to this supply, the back panel 400 drives the scanning line driving circuit 420 and the video line driving circuit 430 to operate the scanning lines 421 and the video lines 431. Accordingly, the back panel 400 can control the orientation of the liquid crystal molecules of the liquid crystal display unit 410 and display an image based on the light emitted from the backlight 600.

The front image signal and the rear image signal have the same image content, but have different brightness. Accordingly, images of the same content are displayed on the front panel 300 and the back panel 400 with different luminances. Accordingly, the observer 50 can be stereoscopically displayed by using an illusion phenomenon in which two images of the front image displayed by the front panel 300 and the rear image displayed by the rear panel 400 are fused. An image can be displayed.

The front panel 300 and the back panel 400 are arranged with various color filters such as an R (Red) filter, a G (Green) filter, and a B (Blue) filter in accordance with a predetermined arrangement in order to display a color image. . The R filter, the G filter, and the B filter are partitioned by a black matrix formed in a lattice shape by a material that shields at least visible light. Therefore, an array of color filters and a stripe pattern by a black matrix are formed. Furthermore, on the TFT (Thin Film Transistor) substrate of the front panel 300 and the back panel 400, wiring (scanning lines 321 and 421) for connecting the scanning

line driving circuits

320 and 420 and each pixel along the black matrix, Wirings (video lines 331 and 431) connecting the video

line driving circuits

330 and 430 and the respective pixels are arranged to be orthogonal to each other. Therefore, a striped pattern by wiring is formed. Here, the stripe pattern formed by a color filter, a black matrix, wiring, or the like is collectively referred to as a stripe pattern. The stripe pattern formed on the front panel 300 is generically referred to as the front stripe pattern 340, and the stripe pattern formed on the back panel 400 is generically referred to as the back stripe pattern 440. The stripe pattern is not limited to the checkered stripe, and may be a stripe pattern such as a vertical stripe or a horizontal stripe.

FIG. 3 is a diagram showing a moire interference pattern with a two-panel configuration. When the front panel 300 and the back panel 400 are overlapped so that the front stripe pattern 340 and the back stripe pattern 440 are parallel or orthogonal to each other, the moire pattern 110 is visually recognized by the observer 50 as shown in FIG. If the moiré pattern 110 is generated, the visibility of the image displayed on the display device 100 is deteriorated, which is not preferable.

Therefore, in the display device 100 according to the first embodiment, the front stripe pattern 340 is changed to the back stripe pattern 440 by tilting one of the front panel 300 and the back panel 400 relative to the other by a predetermined angle. It is tilted at a predetermined angle relative to it. In other words, the front panel 300 and the back panel 400 are overlapped so that the wiring, black matrix, and color filter are arranged at a predetermined angle. As a result, the pitch of the moire pattern 110 is shortened, and at the same time, the brightness difference between the bright and dark portions of the moire pattern 110 is reduced, and the contrast is lowered. Further, it is possible to make the moire pattern 110 less visible.

FIG. 4 is a diagram illustrating a first example of a two-panel configuration in the display device according to the first embodiment. As a means for inclining the front stripe pattern 340 of the front panel 300 relative to the back stripe pattern 440 of the back panel 400, the front panel 300 is viewed relative to the back panel 400 as viewed from the observer 50 as shown in FIG. You may arrange so that it may incline. At this time, a portion where the image displayable area of the back panel 400 and the image displayable area of the front panel 300 overlap becomes the display surface 120. Note that the rear panel 400 may be disposed to be inclined with respect to the front panel 300.

FIG. 5 is a diagram illustrating a second example of the two-panel configuration in the display device according to the first embodiment. As a means for tilting the front stripe pattern 340 of the front panel 300 relative to the back stripe pattern 440 of the back panel 400, both the front panel 300 and the back panel 400 are tilted when viewed from the observer 50 as shown in FIG. You may arrange as follows. As shown in FIG. 5, both the front panel 300 and the back panel 400 are arranged so as to be inclined, and a portion where the image displayable area of the back panel 400 and the image displayable area of the front panel 300 overlap becomes the display surface 120. . At this time, the second example shown in FIG. 5 has a wider area display than the display surface that can be obtained when one of the front panel 300 or the rear panel 400 is inclined as in the first example shown in FIG. There is an advantage that a surface is obtained.

FIG. 6 is a diagram illustrating a third example of the two-panel configuration in the display device according to the first embodiment. When the front stripe pattern 340 of the front panel 300 is tilted relative to the rear stripe pattern 440 of the rear panel 400, as shown in FIG. It may be designed to place a filter. As a result, wiring and color filters can be minimized and costs can be reduced.

FIG. 7 is a diagram of a fourth example of the two-panel configuration in the display device according to the first embodiment. In the first to third examples shown in FIGS. 4 to 6, components necessary for image display such as wiring, black matrix, and color filter are arranged on a rectangular display panel substrate. However, the present invention is not limited to this, and as shown in FIG. 7, a substrate having a shape with few components necessary for display (for example, a circular shape or a bowl shape) may be used.

Subsequently, the tilt angle when the front stripe pattern 340 of the front panel 300 is tilted relative to the back stripe pattern 440 of the back panel 400 by tilting the front panel 300 relative to the back panel 400. The relationship between the moire pitch (mm) of the moire pattern generated at that time (hereinafter referred to as the panel rotation angle) will be described with reference to FIG.

FIG. 8 is a diagram showing the relationship between the rotation angle of the display panel and the moire pitch according to the first embodiment. The vertical axis | shaft of FIG. 8 shows a moire pitch (mm). The horizontal axis in FIG. 8 indicates a panel rotation angle (degree) that is a relative angle between the front panel 300 and the back panel 400. In obtaining the measurement results of FIG. 8, the distance between the front panel 300 and the back panel 400 is fixed to 5 mm. Then, a change in moire pitch was measured when a 20 × magnification camera was installed at a position about 10 cm from the front panel 300 toward the observer 50 and the panel rotation angle was changed. The measurement was performed on a pair of front panel 300 and rear panel 400 having pixel pitches of 0.113 mm, 0.179 mm, and 0.252 mm, respectively.

As shown in FIG. 8, the moire pitch rapidly decreases as the angle increases from the state where the wiring, the black matrix, and the color filter are parallel (panel rotation angle is 0 degree) by changing the panel rotation angle. Moire is less visible. The moiré pitch clearly has a minimum value near 30 degrees regardless of the pixel pitch. When the panel rotation angle exceeded 30 degrees, the moire pitch increased, and a local value was obtained in the vicinity of 45 degrees. Next, when the panel rotation angle exceeded 45 degrees, the moire pitch became smaller and took a minimum value in the vicinity of 60 degrees. And when the panel rotation angle exceeded 60 degrees, the moire pitch increased rapidly.

At this time, when an enlarged image taken by an enlarged camera arranged in front of the front panel 300 is visually observed, moire is generally visually recognized when the panel rotation angle is 20 degrees or more and less than 45 degrees and when it is greater than 45 degrees and less than 70 degrees. It became difficult to be done. When the panel rotation angle is around 30 degrees and around 60 degrees, the contrast between the dark part and the bright part of the moire was particularly low. On the other hand, when the panel rotation angle was around 45 degrees, the contrast between the dark part and the bright part of the moire increased, and at the same time, moire parallel to and perpendicular to the wiring, the black matrix, and the color filter of the rear panel 400 was visually recognized.

From the above results, the angle formed by each stripe pattern (for example, wiring, black matrix, and color filter) of the front panel 300 and the back panel 400 is 20 degrees or more and less than 45 degrees, and preferably about 30 degrees. Deploy. Or it arrange | positions so that it may become larger than 45 degree | times and below 70 degree | times, Preferably it is about 60 degree | times. Thereby, the front panel 300 and the back panel 400 can be arrange | positioned at the optimal angle which reduces generation | occurrence | production of a moire. The observer 50 can enjoy video display comfortably with high visibility.

Subsequently, as an example of the DFD display device 100, the transmission axis 201 of the front polarizing plate 200, the transmission axis 501 of the rear polarizing plate 500, and the liquid crystal of the front panel 300 when used in a liquid crystal display type display device. The alignment direction 301 of molecules and the alignment direction 401 of liquid crystal molecules of the back panel 400 will be described.

FIG. 9A, FIG. 9B, and FIG. 10 are diagrams illustrating an example when the DFD method is applied to the liquid crystal display device. FIG. 9A shows a display device in which, when the front polarizing plate 200, the front panel 300, the rear panel 400, and the rear polarizing plate 500 are arranged to overlap each other, each panel is not inclined relative to the other panels. . FIG. 9B shows the relationship between the orientation direction 401 and the wiring, black matrix, and color filter of the back panel 400 in FIG. 9A. A plurality of patterns as shown in FIG. 9B are formed on the back panel 400, and color filters are provided in sections separated by the lattice 350. The lattice is formed by a black matrix or wiring. At this time, the stripe pattern is not inclined with respect to the alignment direction 401. On the other hand, the relationship between the wiring of the front panel 300 in FIG. 9A, the black matrix, the color filter, and the orientation direction 401 is the same as that in FIG. 9B. That is, the stripe pattern is parallel or perpendicular to the

alignment directions

301 and 401.

In the example shown in FIG. 9A, the transmission axis 201 indicating the deflection direction of the light transmitted through the front polarizing plate 200 is the screen vertical direction, while the transmission axis 501 indicating the deflection direction of the light transmitted through the rear polarizing plate 500 is the horizontal screen. Direction (perpendicular to the transmission axis 201). In addition, the alignment direction 301 of the liquid crystal molecules on the front panel 300 and the alignment direction 401 of the liquid crystal molecules on the back panel 400 are both horizontal to the screen. In the example of the display device shown in FIG. 9A, when both the front panel 300 and the rear panel 400 are in a black display state, the polarized light transmitted through the rear polarizing plate 500 remains unchanged without changing the polarization direction. Pass 300 and reach the front polarizing plate 200. Since the transmission axis 201 of the front polarizing plate 200 forms 90 ° with the polarization axis of the polarized light that has reached the front polarizing plate 200, it cannot pass through the front polarizing plate 200. As a result, the display device can display black. However, as described with reference to FIGS. 9A and 9B, the wiring, black matrix, and color filter of the back panel 400 and the front panel 300 are parallel or vertical, so that moire occurs.

On the other hand, FIG. 10 shows that the front panel 300 and the front polarizing plate 200 are inclined relative to the back panel 400 and the rear polarizing plate 500 in order to reduce the occurrence of moire as shown in the first embodiment. A display device is shown. Note that the front panel 300 and the back panel 400 have the same configuration as that in FIG. 9B, and the stripe pattern is parallel or perpendicular to the

orientation directions

301 and 401. At this time, since the wiring, black matrix, and color filter of the front panel 300 and the back panel 400 overlap each other at a predetermined angle, the occurrence of moire is reduced.

However, when the stripe pattern is overlapped at a predetermined angle, the black display becomes white. That is, when both the front panel 300 and the back panel 400 are in a black display state, the polarized light transmitted through the back polarizing plate 500 passes through the back panel 400 and reaches the front panel 300 without changing the polarization direction. . On the other hand, since the front panel 300 forms a predetermined angle with the back panel 400, the linearly polarized light that has reached the front panel 300 is converted into elliptically polarized light by birefringence, for example, and transmitted to reach the front polarizing plate 200. In the polarized light that has become elliptically polarized light, the polarization component in the direction of the transmission axis 201 of the front polarizing plate 200 is transmitted through the front polarizing plate 200. For this reason, although the generation of moire is reduced, the black display becomes white.

Therefore, a front panel 1300 and a front polarizing plate 1200 are formed as shown in FIGS. 11A and 11B.

FIG. 11A and FIG. 11B are diagrams illustrating an example when the DFD method is applied to the display device. In the display device shown in FIG. 11A, the front panel 1300 and the front polarizing plate 1200 are inclined relative to the rear panel 400 and the rear polarizing plate 500, and the transmission axis 201 and the transmission axis 501 are orthogonal to each other. is doing. Further, the orientation direction 1301 and the orientation 401 are configured to be orthogonal to the transmission axis 1201.

Here, the front panel 1300 will be described with reference to FIG. 11B. In the front panel 1300, unlike FIG. 9B, the orientation direction 1301 is determined to be a predetermined direction regardless of the direction of the grating 350. As a result, the polarized light transmitted through the rear polarizing plate 500 passes through the rear panel 400 and reaches the front polarizing plate 1200 without changing the polarization direction, but the transmission axis 1201 of the front polarizing plate 1200 has a front polarizing plate. Since it forms 90 ° with the polarization axis of the polarized light that has reached 1200, it cannot be transmitted through the front polarizing plate 1200. Thereby, generation | occurrence | production of a moire can be reduced and a whitening can be suppressed simultaneously.

9A to 11B are examples of the alignment direction of the liquid crystal and the transmission axis direction of the polarizing plate, and even if the orientation differs depending on the type of liquid crystal, whitening can be suppressed by applying the same idea.

(Other embodiments)
As described above, the first embodiment has been described as an example of the technique disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can also be applied to embodiments that have been changed, replaced, added, omitted, and the like. Moreover, it is also possible to combine each component demonstrated in the said Embodiment 1, and it can also be set as a new embodiment.

For example, in the first embodiment, the case where two display panels are overlapped has been described, but the present invention is not limited to this. The present disclosure can be applied even when three or more display panels are used in an overlapping manner.

The components described in the attached drawings and detailed description include not only components essential for solving the problem but also components not essential for solving the problem in order to exemplify the above technique. Can be. Therefore, it should not be immediately recognized that these non-essential components are essential as those non-essential components are described in the accompanying drawings and detailed description.

In addition, since the above-described embodiment is for illustrating the technique in the present disclosure, various modifications, replacements, additions, omissions, and the like can be performed within the scope of the claims or an equivalent scope thereof.

The present disclosure is applicable to various display devices such as a television receiver, a digital signage terminal, an electronic blackboard, a large touch panel device, a tablet terminal, a smartphone terminal, and a personal computer monitor, as long as the display device has a plurality of display panels. Applicable.

50 observer 100 display device 110 moire pattern 120

display surface

200,1200

front polarizing plate

201,1201

transmission axis

300,1300 front panel 301,401,1301 orientation direction 310 liquid crystal display unit 320 scanning line drive circuit 321 421 scanning line 330 Video

line drive circuit

331, 431 Video line 340 Front stripe pattern 350 Lattice 400 Rear panel 410 Liquid crystal display unit 420 Scanning line drive circuit 430 Video line drive circuit 440 Back stripe pattern 500 Rear polarizing plate 501 Transmission axis 600 Backlight 700 Control circuit board 710 Backlight control circuit 720 AC / DC (AC / DC) converter 730 Front image control circuit 740 Rear image control circuit

Claims

A first display panel in which pixels are formed in a region partitioned by a first stripe pattern;
A second display panel in which pixels are formed in a region partitioned by a second stripe pattern,
The display device, wherein the first display panel and the second display panel are arranged to overlap each other, and the first stripe pattern is inclined at a predetermined angle with respect to the second stripe pattern.
The first stripe pattern is inclined at a desired angle with respect to the second stripe pattern by arranging the first display panel to be inclined with respect to the second display panel. The display device described.
A first wiring disposed along the first stripe pattern;
A second wiring disposed along the second stripe pattern, and
3. The first wiring is inclined at a predetermined angle with respect to the second wiring by arranging the first display panel so as to be inclined with respect to the second display panel. The display device described in 1.
The region where the first display panel and the second display panel overlap each other when the first display panel is disposed to be inclined with respect to the second display panel is used as a display surface. 4. The display device according to any one of 3.
5. The display device according to claim 1, wherein the predetermined angle has an acute angle component of 20 ° or more and less than 45 °.
The display device according to claim 5, wherein the predetermined angle has an acute angle component of approximately 30 °.
5. The display device according to claim 1, wherein the predetermined angle has an acute angle component larger than 45 ° and smaller than 70 °.
The display device according to claim 7, wherein the predetermined angle has an acute angle component of approximately 60 °.
A first polarizing plate having a first transmission axis, and a second polarizing plate having a second transmission axis,
Arranged in order of the first polarizing plate, the first display panel, the second display panel, the second polarizing plate,
The display device according to claim 1, wherein the first transmission axis and the second transmission axis are arranged so as to be orthogonal or parallel to each other.
A first polarizing plate having a first transmission axis, and a second polarizing plate having a second transmission axis,
The first display panel is a liquid crystal display panel according to a first liquid crystal alignment direction, and the second display panel is a liquid crystal display panel according to a second liquid crystal alignment direction;
Arranged in order of the first polarizing plate, the first display panel, the second display panel, the second polarizing plate,
The first transmission axis and the second transmission axis are arranged so as to be orthogonal or parallel to each other, and the first liquid crystal alignment direction, the second liquid crystal alignment direction, and the first The display device according to claim 1, wherein the transmission axis is arranged so as to be orthogonal or parallel to the transmission axis.