CN101354120B - Light source, display device, portable terminal device, and ray direction switching element - Google Patents

Abstract

A light source is proposed, including: a backlight that emits light in a planar shape; a beam direction adjustment element that adjusts the direction of light incident from the backlight and emits the light, wherein the light is alternately formed in a direction perpendicular to its light adjustment direction. a transparent region for transmitting light and an absorbing region for absorbing light; and a transparent and scattering switching element capable of switching between a state of transmitting light incident from the beam direction adjusting element and a state of scattering light.

Description

Light source, display device, portable terminal device and beam direction switching element

This application is a divisional application of Application No. 200510072817.0 entitled "Light Source, Display Device, Portable Terminal Device, and Beam Direction Switching Element" filed by NEC Corporation to the State Intellectual Property Office of China on May 23, 2005.

technical field

The present invention relates to a light source, a display device, a portable terminal device and a light beam direction switching element, more particularly, to a light source capable of changing the irradiation angle of illumination light, a light source capable of changing A display device of an angle of view, a portable terminal device using the display device, and a beam direction switching element included in the light source.

Background technique

With the development of technology in recent years, a liquid crystal display device (LCD) having a wider viewing angle (ie, vertically visible in a wider range of angles) has been put into use. In addition, portable information terminals equipped with LCDs are also widely used. In such a portable information terminal, when a user watches information displayed on the LCD with other people, it is required that the LCD has a wide viewing angle. On the other hand, in portable information terminals, users generally do not want others to view displayed information. In this case, the LCD is required to have a narrower viewing angle. In this way, the angle of view needs to be wider or narrower depending on the state in which the LCD is used. Conventionally, LCDs satisfying such demands have been proposed.

24(a) and 24(b) schematically show a conventional liquid crystal display device described in Japanese Patent Laid-Open Publication No. 6-59287. Fig. 24(a) shows the liquid crystal display device when no voltage is applied thereto. Fig. 24(b) shows the liquid crystal display device when a voltage is applied thereto. As shown in FIGS. 24( a ) and 24 ( b ), the first conventional liquid crystal display device includes a liquid crystal panel in which a liquid crystal material (not shown) is sealed by transparent substrates 102 and 108 . A polarizing plate 101 is provided on one surface of the liquid crystal panel. A guest-host liquid crystal cell 131 is disposed on the other surface. The guest-host liquid crystal unit 131 includes two transparent substrates 114 on which transparent electrodes 110 are disposed. Two transparent substrates 114 seal a liquid crystal material including liquid crystal molecules 131a and elongated dye molecules 131b. The dye molecule 131b absorbs light more in the direction of the minor axis of the molecule than in the direction of the major axis. When no voltage is applied to the guest-host liquid crystal cell 131 , the liquid crystal molecules 131 a and the elongated dye molecules 131 b are aligned longitudinally parallel to the surface of the transparent substrate 114 . When a voltage is applied to the guest-host liquid crystal cell 131 , the liquid crystal molecules 131 a and the elongated dye molecules 131 b are aligned vertically to the surface of the transparent substrate 114 in the longitudinal direction. The polarizing plate 101 is disposed on a surface of the liquid crystal panel on an opposite side from the surface of the liquid crystal panel opposite to the guest-host liquid crystal cell 131 .

In this first conventional liquid crystal display device, light in a wide angle range passes through the liquid crystal panel and is incident on the guest-host liquid crystal cell 131 . When displaying an image with a wider viewing angle, no voltage is applied to the guest-host liquid crystal unit 131, so that the light absorption direction of the guest-host liquid crystal unit 131 coincides with that of the polarizing plate 101, whereby the light directly passes through the guest-host liquid crystal unit 131. Liquid crystal unit 131. Therefore, the display screen can be visually recognized in a wide range of angles.

When an image is displayed with a narrower viewing angle, a voltage is applied to the guest-host liquid crystal unit 131, and the dye molecules 131b are arranged on the surface of the transparent substrate 114 along the longitudinal direction, and the incident angle of light deviates greatly from the surface phase of the transparent substrate 114. vertical direction. The dye molecules 131b absorb light, and the light cannot pass through the guest-host liquid crystal cell 131 . Therefore, even though the angular distribution of the light incident on the display device is wide, the angular distribution of the emitted light can still be narrowed by the absorption of the guest-host liquid crystal. Therefore, it is possible to reduce the size of the display plane for visual recognition.

FIG. 25 is a diagram schematically showing a second conventional liquid crystal display device described in Japanese Patent Laid-Open Publication No. 10-197844. The second conventional liquid crystal display device includes a backlight 113 as shown in FIG. 25 . On the backlight 113 is disposed a PDLC cell 136 sandwiching a polymer dispersed liquid crystal (PDLC) layer 111 between two transparent substrates 109 . A polarizing plate 101 is disposed on the PDLC unit 136 , and a twisted nematic liquid crystal display (TN-LCD) is disposed on the polarizing plate 101 . A guest-host liquid crystal cell is disposed on the TN-LCD, and a polarizing plate 101 is disposed on the guest-host liquid crystal cell. This guest-host liquid crystal cell has the same structure as the guest-host liquid crystal cell used in the first conventional liquid crystal display device as described in Japanese Patent Laid-Open Publication No. 6-59287.

In the second conventional liquid crystal display device, the wide viewing field display and the narrow viewing field display are switched by switching the voltage applied to the guest-host liquid crystal cell. In addition, the transmission and reflection of light are switched by switching the voltage applied to the PDLC cell to adjust the brightness of the display screen.

Japanese Patent Laid-Open No. 11-142819 discloses a liquid crystal display device in which a converging element composed of a prism sheet and a light scattering element composed of a PDLC cell are disposed between a light source and a liquid crystal panel. Japanese Patent Unexamined Publication No. 11-142819 mentions that it is possible to increase the directivity of light by using a prism sheet, and then use a PDLC cell to transmit or scatter the light from the prism sheet, and to perform a process between a narrow field of view and a wide field of view. switch. Furthermore, Japanese Patent Laid-Open No. 9-105907 discloses a similar liquid crystal display device in which an optical element composed of a PDLC cell is provided between a light source and a liquid crystal panel.

On the other hand, conventionally, a highly collimated backlight has been proposed in which the irradiation angle of the illumination light is fixed but the directivity in a specific direction such as the front is improved (for example, see the monthly "Display", 2004 5 month, pp. 14-17). FIG. 26 is a perspective view showing a conventional highly collimated backlight 213 described in the monthly "Display", May 2004, pp. 14-17. As shown in FIG. 26 , in this conventional highly collimated backlight 213 , LEDs 201 are disposed in positions where light guide plate 202 is disposed, and linear microprisms are disposed in light guide plate 202 centering on LEDs 201 . A prism sheet 203 in which the prism structure is also arranged centering on the LED 201 is arranged on the light emitting surface of the light guide plate 202 . Further, a reflective sheet 204 is provided on the surface on the opposite side to the surface of the light guide plate 202 on which the prism sheet 203 is provided.

The output light from the LED 201 is incident on the light guide plate 202 and radially emitted along the surface of the light guide plate 202 through the linear microprisms formed in the light guide plate 202 . Here, the LED is arranged at one position of the light guide plate 202, and the longitudinal direction of the linear microprism formed in the light guide plate 202 is arranged so as to be substantially perpendicular to the LED 201. Therefore, even if the light introduced through the light guide plate 202 collides with the linear microprisms, the light is not deflected in the longitudinal direction of the linear microprisms, but travels linearly and radially around the LEDs 201 . The prism sheet 203 refracts the light emitted from the light guide plate 202 and deflects it in a vertical direction with respect to the light emitting surface of the light guide plate 202 . Therefore, a highly collimated backlight with two-dimensionally improved directivity along the front is realized.

However, the above-mentioned conventional techniques have the following typical problems. In the liquid crystal display device described in Japanese Patent Laid-Open Publication No. 6-59287, the difference in the amount of light absorption is small in the direction of the minor axis and the direction of the major axis of the dye molecules located in the guest-host liquid crystal cell. In other words, the dye is less dichroic. In addition, the liquid crystal molecules near the transparent substrate do not stand when a voltage is applied, and the dye molecules remain aligned parallel to the transparent substrate. Therefore, in the guest-host liquid crystal cell when a voltage is applied, the efficiency of absorbing light whose incident angle is largely deviated from the direction perpendicular to the surface of the transparent substrate decreases, and the viewing angle in the narrow viewing field increases.

Furthermore, in the liquid crystal display device described in Japanese Patent Unexamined Publication No. 10-197844, switching between wide-field display and narrow-field display is also performed by switching the voltage applied to the guest-host liquid crystal unit of. Therefore, there are the same problems as those of the liquid crystal display device described in Japanese Patent Laid-Open Publication No. 6-59287.

Furthermore, in the liquid crystal display device described in Japanese Patent Laid-Open Publication No. 11-142819, the light from the light source is condensed by the prism sheet, that is, the directivity of the light is improved. Highly collimated light passes directly through the PDLC cell, thereby reducing the size of the visually recognizable display screen. However, since the prism sheet does not have a sufficient effect of improving the directivity of light, the angle of view increases during narrow-field display. In other words, other people can view the displayed information.

Contents of the invention

The present invention has been made in consideration of the above-mentioned typical and other problems, and the typical feature of the present invention is to provide a light source having an illumination light irradiation angle with a large variable width, a light source with a large variable width using the light source, A display device with an angle of view, a portable terminal device using the display device, and a beam direction switching element included in the light source.

A light source according to a typical solution of the present invention includes: a backlight emitting planar light; a beam direction adjustment element adjusting the direction of light incident from the backlight and emitting the light, wherein the direction perpendicular to its light adjustment direction is alternately A transparent area for transmitting light and an absorption area for absorbing light are formed; and a transparent and scattering switching element capable of switching between a state of transmitting light incident from the beam direction adjustment element and a state of scattering light.

In the present invention, a light beam direction adjustment element for controlling the direction of light and a transparent and scattering switching element capable of switching between transparent and scattering states according to the on-off of the applied voltage are arranged between the backlight and the liquid crystal panel, Thereby, the variable width of the irradiation angle of light in the light source can be increased.

Preferably, the emission direction of the light emitted by the backlight is elliptical and radially expanded with respect to the direction perpendicular to the emitting surface, and the transparent regions of the beam direction adjustment element are alternately formed along the direction parallel to the long axis direction of the ellipse and absorption area.

Preferably, the emission direction of the light emitted from the backlight is elliptical and radially expanded with respect to the direction perpendicular to the emitting surface, and in the beam direction adjusting element, alternately formed along the direction parallel to the minor axis direction of the ellipse Transparent and absorbing regions of the beam direction adjusting element. Therefore, the light quantity of the backlight by the light beam direction adjustment element is increased, and a bright light source can be realized.

The emission direction of the light emitted from the backlight may be converged circularly or radially with respect to the direction perpendicular to the emission surface. Therefore, since the absorption loss of light by the light beam direction adjusting element can be reduced, bright display can be realized. In addition, since the directivity of the backlight is two-dimensional, it is possible to switch between narrow field of view display and wide field of view display for a direction perpendicular to the direction in which the transparent regions and absorbing regions of the light beam direction adjustment elements are alternately arranged.

Preferably, in the transparent and scattering switching element, a polymer/liquid crystal composite layer comprising liquid crystal molecules and polymers is sandwiched between a pair of flat electrodes, in which the polymer/liquid crystal composite layer is located when a voltage is applied between the flat electrodes The polymer/liquid crystal composite layer is in a state where incident light is transmitted, and when no voltage is applied between the flat electrodes, the polymer/liquid crystal composite layer is in a state where the polymer/liquid crystal composite layer scatters incident light. Therefore, since the transparent and diffuse switching element does not consume electric power in a state where the transparent and diffuse switching element scatters incident light, electric energy is distributed to the backlight light source. Therefore, the luminance of the light source in the scattering state can be improved.

After the application of the voltage is stopped, the orientation state of the liquid crystal molecules when the voltage is applied thereto can be maintained.

The transparent and diffuse switching element and the beam direction adjusting element can be integrally formed. Therefore, since the beam direction adjusting element can be supported by the transparent and scattering switching element, a highly stable thin light source can be realized.

The transparent and diffuse switching element and the beam direction adjusting element may have a common substrate.

The substrate of the beam direction adjusting element may simply be the substrate shared by the beam direction adjusting element and the transparent and diffuse switching element. Therefore, the thickness of the light source can be further reduced. Furthermore, preferably, the light quantity of the backlight and the transparent and diffuse states of the transparent and diffuse switching element can be independently set. Therefore, the intensity and directivity of light emitted from the light source can be set in various ways.

It is also possible that, when no voltage is applied between the flat electrodes, the transparent and scattering switching element is in a state in which the transparent and scattering switching element scatters incident light, and that when the transparent and scattering switching element is used in the scattering state, the voltage Applied to transparent and diffuse switching elements. Therefore, when the transparent and scattering switching element is used in a scattering state, it is possible to increase the front luminance without significantly reducing the luminance in oblique directions.

A display device according to another typical solution of the present invention includes: a backlight emitting planar light; a light beam direction adjustment element adjusting the direction of light incident from the backlight and emitting the light, wherein The direction alternately forms a transparent area for transmitting light and an absorption area for absorbing light; a transparent and scattering switching element capable of switching between a state of transmitting light incident from the light beam direction adjustment element and a state of scattering light; and a liquid crystal panel utilizing Light incident from the transparent and diffuse switching elements displays an image.

In the present invention, a light beam direction adjustment element for controlling the direction of light and a transparent and scattering switching element capable of switching between transparent and scattering states according to the on-off of the applied voltage are arranged between the backlight and the liquid crystal panel, Thereby, the variable width of the viewing angle of the display device can be increased.

Preferably, the emission direction of the light emitted by the backlight is elliptical and radially expanded with respect to the direction perpendicular to the emitting surface, and in the beam direction adjustment element, alternately formed along the direction parallel to the major axis direction of the ellipse Transparent and absorbing regions of the beam direction adjusting element.

White light sources can consist of blue LEDs and yellow phosphors, with pulse modulation to adjust the amount of light. Therefore, it is possible to control the chromaticity change of the display device while adjusting the light quantity of the white light source while switching between transparency and diffusion.

The direction in which the transparent regions and the absorbing regions of the light beam direction adjusting member are alternately formed and the pixel arrangement direction of the display panel are not necessarily parallel to each other. Accordingly, it is possible to reduce moire due to the beam direction adjusting element and the display panel.

The display panel may be a liquid crystal panel, and the liquid crystal panel may be a panel of a transverse electric field mode, a multi-domain vertical alignment mode, or a thin film compensation TN mode. Thus, it is possible to control the hue change and improve visibility when the transparent and diffusive switching element is in the diffusive state.

The portable terminal device can have an adjustment device which can change the amount of backlight and the transparent and diffuse state of the transparent and diffuse switching element independently of each other. Therefore, the user can set the optimum state according to the environment in which the portable terminal device is used.

The portable terminal device may have electric energy accumulating means, remaining amount detecting means for electric energy accumulated in the electric energy accumulating means, and control means for automatically changing the backlight amount and the transparent and scattering switching element according to the detected remaining amount information transparent and scattering states. When the transparent and scattering switching element is made transparent, since the light quantity of the backlight can be reduced, it is possible to reduce power consumption when the remaining battery power is low, and extend the operating time of the portable terminal device.

The transparent area and the absorbing area of the transparent and scattering switching element may be alternately formed in the lateral direction of the portable terminal device. Therefore, the variable width of the viewing angle in the lateral direction of the portable terminal device can be increased.

The beam direction switching element according to the present invention is characterized in that the beam direction adjusting element adjusts the direction of incident light and emits the light, and the transparent and scattering switching element is integrally formed. The element can be switched between a state of transmitting light incident from the beam direction adjustment element and a state of scattering light. Therefore, since the beam direction adjusting element can be supported by the transparent and scattering switching element, a highly stable thin beam direction switching element can be realized.

In the beam direction switching element, the transparent and scattering switching element and the beam direction adjusting element may be formed on a common substrate. The substrate of the beam direction adjusting element may simply be the substrate shared by the beam direction adjusting element and the transparent and diffuse switching element.

According to a typical solution of the present invention, a light beam direction adjustment element for controlling the direction of light and a transparent and scattering switch capable of switching between transparent and scattering states according to the on-off of the applied voltage are arranged between the backlight and the liquid crystal panel element. Therefore, it is possible to increase the variable width of the irradiation angle of light in the light source, and to increase the variable width of the viewing angle of a liquid crystal display device using such a light source.

Description of drawings

1 is a sectional view showing a liquid crystal display device according to a first exemplary embodiment of the present invention;

2 is a perspective view showing an example of a backlight used in a liquid crystal display device according to a first exemplary embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating directions of light emitted from a backlight;

4 is a plan view showing an example of a louver used in a liquid crystal display device according to a first exemplary embodiment of the present invention;

5 is a schematic diagram illustrating light distribution characteristics of a liquid crystal display device at a wide viewing angle according to a first exemplary embodiment of the present invention;

6 is a schematic diagram illustrating light distribution characteristics of a liquid crystal display device at a narrow viewing angle according to a first exemplary embodiment of the present invention;

7 is a plan view showing an example of a louver used in a liquid crystal display device according to a first modification of the first exemplary embodiment of the present invention;

8 is a plan view showing an example of a shutter used in a liquid crystal display device according to a second modification of the first exemplary embodiment of the present invention;

9 is a schematic view showing light distribution characteristics of a liquid crystal display device according to a third modification of the first exemplary embodiment of the present invention at a wide viewing angle;

10 is a schematic view showing light distribution characteristics of a liquid crystal display device according to a third modification of the first exemplary embodiment of the present invention at a narrow viewing angle;

11 is a sectional view showing a liquid crystal display device according to a second exemplary embodiment of the present invention;

12 is a sectional view showing a liquid crystal display device according to a third exemplary embodiment of the present invention;

13 is a sectional view showing a liquid crystal display device according to a fourth exemplary embodiment of the present invention;

14 is a sectional view showing a liquid crystal display device according to a fifth exemplary embodiment of the present invention;

15 is a sectional view showing a liquid crystal display device according to a sixth exemplary embodiment of the present invention;

16 is a sectional view showing a liquid crystal display device according to a seventh exemplary embodiment of the present invention;

17 is a sectional view showing a liquid crystal display device according to an eighth exemplary embodiment of the present invention;

18 is a sectional view showing a liquid crystal display device according to a ninth exemplary embodiment of the present invention;

19 is a sectional view showing a liquid crystal display device according to a tenth exemplary embodiment of the present invention;

Figure 20 is a graph showing experimental results of applying a small voltage to transparent and scattering switching elements in a scattering state to tune scattering properties;

21 is a perspective view showing a portable terminal device mounted with a liquid crystal display device of the present invention;

22 is a plan view showing a transparent and scattering switching element of a liquid crystal display device according to a twelfth exemplary embodiment of the present invention;

23 is a plan view showing a liquid crystal display device in which directions of transparent regions and absorbing regions of light beam direction adjustment elements are alternately formed and directions of pixel arrangement of a liquid crystal display panel are not parallel to each other;

FIG. 24(a) is a schematic diagram schematically showing a first conventional liquid crystal display device when no voltage is applied thereto;

FIG. 24(b) is a schematic diagram schematically showing a first conventional liquid crystal display device when a voltage is applied thereto;

25 is a schematic diagram schematically showing a second conventional liquid crystal display device; and

FIG. 26 is a perspective view showing a conventional highly collimated backlight.

Detailed ways

Hereinafter, exemplary embodiments of the present invention will be explained in detail with reference to the accompanying drawings. First, a first embodiment of the present invention will be explained. FIG. 1 is a cross-sectional view showing a liquid crystal display device according to a first exemplary embodiment of the present invention. 2 is a perspective view showing an example of a backlight used in a liquid crystal display device according to a first exemplary embodiment of the present invention. FIG. 3 is a schematic diagram showing directions of light emitted from a backlight. 4 is a plan view showing an example of a shutter used in the liquid crystal display device according to the first exemplary embodiment of the present invention. 5 is a schematic diagram showing light distribution characteristics of a liquid crystal display device at a wide viewing angle according to a first exemplary embodiment of the present invention. FIG. 6 is a schematic diagram showing light distribution characteristics of a liquid crystal display device at a narrow viewing angle according to a first exemplary embodiment of the present invention.

As shown in FIG. 1 , in the liquid crystal display device according to the first embodiment, a backlight 13 is provided, and a louver 12 (beam direction adjusting member) is provided on the backlight 13 . The transparent and scattering switching element 22 is disposed on the louver 12 , and the liquid crystal panel 21 is disposed on the transparent and scattering switching element 22 . Set up the light source, including the backlight, beam direction adjustment elements, and transparent and diffuse switching elements.

As shown in FIG. 2 , a prism-shaped line light source 36 is arranged along one end surface of the backlight 13 , and white LEDs 25 are arranged opposite to its two ends. The line light source 36 includes a plurality of prisms (not shown), arranged in a ring, for refracting the light incident on the line light source 36 from the white LED 25 along the direction substantially perpendicular to the backlight 13 and the plurality of prisms. In this way, the line light source 36 emits line-shaped light from the side of the backlight 13 in the direction of the backlight 13 . In addition, the backlight 13 includes a plurality of prisms (not shown) annularly arranged in a direction perpendicular to a surface extending parallel to the line light source 36 and opposite to the line light source 36 . These prisms refract linear light incident from the line light source 36 in a direction perpendicular to one surface 37 of the backlight 13 , and emit planar light from the entire surface 37 . The backlight 13 emits light such that light in a direction parallel to the line light source 36 has a wider angle than light in a direction normal to the line light source 36 .

As shown in FIG. 3 , the direction 35 of light emitted from the backlight 13 is defined by the polar angle θ and the azimuth angle φ. The polar angle θ is the angle formed by the direction 35 and the direction 34 perpendicular to the surface of the backlight 13 . On the projection surface 33 parallel to the backlight 13, when taking the X-Y rectangular coordinates and taking the point where the direction 34 and the projection surface 33 intersect each other as the origin 0, the azimuth φ is defined by the sum of the intersection point where the connection direction 35 and the projection surface 33 intersect each other The angle formed by the line at origin 0 and the X-axis. In this way, the light emitted from the backlight 13 is diffused light, and θ and φ have wide distributions.

As shown in FIG. 1 , the louver 12 is a beam direction adjustment element for improving the directivity of light emitted from the backlight 13 . The louver 12 adjusts the broadened light incident from the backlight 13 in one direction, and emits the light. For example, this light adjustment direction is a direction perpendicular to the surface of the louver 12 . Regarding the light emitted from the louver 12, the directivity of the light in the direction perpendicular to the surface of the louver 12 (light adjustment direction) is enhanced. In this case, the light emitted in the direction adjusted by the louver 12 is slightly broadened although the polar angle θ is smaller than that of the light emitted from the backlight 13 as shown in FIG. 3 .

For example, in the louver 12 , transparent regions 12 a that transmit light and absorption regions 12 b that absorb light are alternately arranged in a direction parallel to the surface of the louver 12 . For example, the direction in which the transparent regions 12 a and the absorbing regions 12 b are alternately arranged is equal to the direction in which the backlight 13 emits wide-angle light, that is, the direction parallel to the line light source 36 . As shown in FIG. 4, when viewed from a direction perpendicular to the surface of the louver 12, strip-shaped transparent regions 12a and absorbing regions 12b are alternately arranged. For example, the louver 12 can adjust the arrangement pitch of the transparent region 12a and the absorbing region 12b and the amount of light absorbed in the absorbing region 12b, so as to adjust the outgoing angle of the incident light.

A transparent and diffuse switching element comprising a polymer/liquid crystal composite layer is sandwiched between a pair of flat electrodes. The polymer/liquid crystal composite layer includes liquid crystal molecules and polymers. For example, a polymer diffused liquid crystal layer in which liquid crystal groups are diffused into a polymer film, a mixture including an LC layer in which polymer fibers are added to the liquid crystal, a mixture including an LC layer in which beads are added to the liquid crystal , a mixture including an LC layer in which liquid crystal microcapsules are diffused in a polymer, or a mixture including an LC layer in which a liquid crystal material is properly disposed in a polymer matrix is used as a polymer/liquid crystal composite layer.

As shown in FIG. 1, in the transparent and scattering switching element 22, the PDLC layer 11 formed by dispersing the liquid crystal group 11b in the polymer matrix 11a is placed in the electrodes 10, and a transparent substrate 9 is provided on each electrode 10 . A voltage is applied to the PDLC layer 11 sandwiched between the electrodes 10 through the electrodes 10, thereby changing the orientation state of the liquid crystal molecules in the PDLC layer 11. For example, the PDLC layer 11 is formed by exposing a photocurable resin and a liquid crystal material to light and hardening the mixture. The transparent and scattering switching element 22 scatters or transmits light incident from the louver 12 and directs the light toward the liquid crystal panel 21 .

In the liquid crystal panel 21 , a polarizing plate 1 that polarizes light incident from the transparent and scattering switching element 22 is provided, and a transparent substrate 8 is provided on the polarizing plate 1 . Pixel electrodes 7 defining pixel regions are provided on a transparent substrate 8 in a matrix shape. A liquid crystal layer 6 is provided to cover the surface of the pixel electrode 7 and the transparent substrate 8 . A common electrode 5 for applying a voltage to the liquid crystal layer 6 is provided on the liquid crystal layer 6 , and a transparent dielectric layer 4 is provided on the common electrode 5 . In the transparent dielectric layer 4, a groove is formed at a position corresponding to the area not covered by the pixel electrode 7 on the surface of the transparent substrate 8, and a black matrix for preventing external light from being projected onto the liquid crystal panel is arranged in the groove 3. A transparent substrate 2 is provided to cover the transparent dielectric layer 4 and the black matrix 3 , and a polarizing plate 1 for polarizing outgoing light from the liquid crystal panel is provided on the transparent substrate 2 .

As shown in FIG. 5 , the light emitted from the backlight 13 has an elliptical distribution 38 that spreads wider in the X direction than in the Y direction. This outgoing light distribution shows that the larger the area of the distribution area, the larger the spread of the light. When light 38 having this distribution is incident on the louver 12, the light propagating in the X direction is absorbed by the louver 12 and changed into light 39 having a highly collimated distribution, which is substantially distributed in a circular shape. In the case of a wide field of view display, when light 39 having such a distribution is incident on the transparent and scattering switching element 22 in a scattering state, the circularly distributed light is uniformly scattered to become a more extended circle Shaped light distribution 40. The light 40 having this distribution is transmitted through the liquid crystal panel 21, and is emitted to realize wide-field display.

As shown in FIG. 6, when light having a distribution 38 is incident on the louver 12, the light propagating in the X direction is absorbed by the louver 12 and becomes light 39 having a highly collimated distribution substantially in a circular shape distribution. In the case of a narrow field of view display, when the light 39 with such a distribution is incident on the transparent and scattering switching element 22 in a transparent state, the circularly distributed light is directly transmitted through the transparent and scattering switching element 22, and exits with Distributes 39 light. The light 39 having this distribution is transmitted through the liquid crystal panel 21, and is emitted to realize a narrow viewing field display.

Next, the operation of the liquid crystal display device according to the first embodiment of the present invention formed as above will be explained. First, the case of wide-field display will be explained. As shown in FIG. 1 , the light emitted from the backlight 13 is made incident on the louver 12 . As shown in FIG. 3, the light emitted from the backlight 13 is diffuse light, and θ and φ have a wide distribution. In the backlight 13 shown in FIG. 2, as shown in FIG. 5, the light emitted from the backlight 13 has a larger θ when it is close to 0 degrees or 180 degrees than when φ is close to 90 degrees or 270 degrees. value. In other words, the light emitted from the backlight 13 has an elliptical distribution 38 that spreads wider in the X direction than in the Y direction. When the light 38 having this distribution is incident on the louver 12 , the light having a larger θ is absorbed by the absorption region 12 b of the louver 12 . Light with a smaller θ is transmitted through the transparent region 11a. Therefore, among the light emitted from the louver 12 , the light having a larger θ is removed, and the highly collimated distributed light 39 having a smaller distribution area is emitted.

As shown in FIG. 1 , highly collimated light exiting the louver 12 with a profile 39 is incident on the transparent and diffusive switching element 22 . In the case of wide-field display, no voltage is applied to the PDLC layer 11 . Accordingly, the PDLC layer 11 is in a state in which the liquid crystal molecules 11b are randomly dispersed in the polymer matrix 11a, and scatters incident light. Therefore, as shown in FIG. 5 , the circularly distributed light 39 is uniformly scattered by the PDLC layer 11 and becomes more widely spread circularly distributed light 40 . In other words, the light whose directivity is increased by scattering by the transparent and diffuse switching element 22 through the louver 12 to have a lower directivity and become light having a wide angle. As shown in FIG. 1 , distributed light 40 spread over a wide range is incident on liquid crystal panel 21 and is emitted while maintaining distribution 40 . In this way, images are displayed with a wider angle of view.

Next, the case of narrow field of view display will be explained. As shown in FIG. 6 , as in the case of wide-field display, the elliptical light distribution 38 emitted from the backlight 13 is transformed into a highly collimated light distribution 39 with a smaller distribution area through the louver 12 .

As shown in FIG. 1 , highly collimated light having a distribution 39 is incident on the transparent and diffuse switching element 22 . In the case of a narrow viewing field display, a predetermined voltage is applied to the PDLC layer 11 . Accordingly, the PDLC layer 11 becomes a transparent state in which the liquid crystal molecules 11b dispersed in the polymer matrix 11a are aligned. In other words, the PDLC layer 11 directly transmits incident light. Therefore, as shown in FIG. 6 , the circularly distributed light 39 is directly transmitted through the PDLC layer 11 . In other words, the light whose directionality has been enhanced by the louvers 12 exits the transparent and diffuse switching element 22 maintaining a highly collimated distribution 39 . As shown in FIG. 1 , light 39 having a highly collimated distribution is incident on the liquid crystal panel 21 and is emitted while maintaining the distribution 39 . In this way, images are displayed with a narrower angle of view.

In this way, the low-directional light emitted from the backlight 13 is converted into highly collimated light by the louver 12, and the highly collimated light is transmitted or scattered by the transparent and scattering switching elements, and the PDLC layer is used to display and display in a narrow field of view. Switch between widefield displays. Therefore, it is possible to increase the variable width of the irradiation angle of the light in the light source, and increase the variable width of the viewing angle of the liquid crystal display device using the light source.

Here, the same liquid crystal display device as in the first exemplary embodiment was constructed using a conventional prism sheet instead of the shutter 12 to measure the relationship between the viewing angle and brightness in the case of a narrow viewing field display. The range of the viewing angle of 0 degrees (that is, the viewing angle at which a luminance value equal to or greater than half the luminance is obtained when the liquid crystal display device is viewed from the front) is 30 degrees to the left and right. On the other hand, in the first embodiment, the range of the viewing angle for obtaining a luminance value equal to or greater than half the luminance of the viewing angle of 0 degrees is 20 degrees to the left and right. In this way, in the first exemplary embodiment, narrow field of view display can be effectively realized as compared with conventional techniques.

Next, a first modification of the first exemplary embodiment of the present invention will be explained. 7 is a plan view showing an example of a shutter used in a liquid crystal display device according to a first modification of the first exemplary embodiment of the present invention. In the first exemplary embodiment described above, as shown in FIG. 4, when the louver 12 is viewed from a direction perpendicular to the surface, the band-shaped transparent regions 12a and the absorbing regions 12b are alternately arranged. Therefore, the directivity of light incident on the louver 12 can only be improved in one direction. On the other hand, in the first modification of the first exemplary embodiment, as shown in FIG. 7, when the louver 12 is viewed from a direction perpendicular to the surface, the circular transparent regions 12a are arranged in a matrix shape in the absorbing regions 12b. Therefore, the directivity of light incident on the louver 12 can be improved in a plurality of directions. The components, operations, and effects of the first modification of the first exemplary embodiment are the same as those of the first exemplary embodiment except for the above.

Next, a second modification of the first exemplary embodiment of the present invention will be explained. 8 is a plan view showing an example of a shutter used in a liquid crystal display device according to a second modification of the first exemplary embodiment of the present invention. In the first modification of the first exemplary embodiment, as shown in FIG. 7, transparent regions 12a are arranged in a matrix shape in absorbing regions 12b. On the other hand, in the second modification of the first exemplary embodiment, as shown in FIG. 8, when the louver 12 is viewed from a direction perpendicular to the surface, quadrangular transparent areas 12a are arranged in the absorbing area 12b in a matrix shape. For example, the transparent area 12a is square or rectangular. Except for the above, the components, operations, and effects of the second modification of the first exemplary embodiment are the same as those of the first modification of the first exemplary embodiment.

Next, a third modification of the first exemplary embodiment of the present invention will be explained. 9 is a schematic view showing light distribution characteristics of a liquid crystal display device according to a third modification of the first exemplary embodiment of the present invention at a wide viewing angle. 10 is a schematic view showing light distribution characteristics of a liquid crystal display device according to a third modification of the first exemplary embodiment of the present invention at a narrow viewing angle.

In the first exemplary embodiment, as shown in FIG. 5 , the light emitted from the backlight 13 has an elliptical distribution 38 that spreads wider in the X direction than in the Y direction. When light 38 having this distribution is incident on the louver 12, the light propagating in the X direction is absorbed by the louver 12 and changed into light 39 having a highly collimated distribution, which is substantially distributed in a circular shape. In the case of a wide field of view display, when light 39 having such a distribution is incident on the transparent and scattering switching element 22 in a scattering state, the circularly distributed light is uniformly scattered to become a more extended circle Shaped light distribution 40. The light 40 having this distribution is transmitted through the liquid crystal panel 21, and is emitted to realize wide-field display. Furthermore, as shown in FIG. 6, when light having a distribution 38 is incident on the louver 12, the light propagating in the X direction is absorbed by the louver 12 and changed into light 39 having a highly collimated distribution, which is substantially Distributed in a circular shape. In the case of a narrow field of view display, when the light 39 with such a distribution is incident on the transparent and scattering switching element 22 in a transparent state, the circularly distributed light is directly transmitted through the transparent and scattering switching element 22, and exits with Distributes 39 light. The light 39 having this distribution is transmitted through the liquid crystal panel 21, and is emitted to realize a narrow viewing field display.

On the other hand, in the third modification of the first exemplary embodiment, as shown in FIG. 9 , the light emitted from the backlight 13 has an elliptical distribution 41 that spreads wider in the Y direction than in the X direction. When the light 41 with this distribution is incident on the louver 12, the directivity of the light propagating in the X direction is further improved by the louver 12, specifically, the light distributed in the X direction is changed into a highly collimated distribution 42. Light. In the case of a wide-field display, when light 42 having such a distribution is incident on the transparent and scattering switching element 22 in a scattering state, the light is scattered so as to spread in the X direction and become distributed light 43 . The light 43 having this distribution is transmitted through the liquid crystal panel 21, and is emitted to realize wide-field display. In addition, as shown in FIG. 10, when the light with distribution 41 emitted from the backlight 13 is incident on the shutter 12, the directivity of the light propagating in the X direction is further improved by the shutter 12, specifically, the distribution in the X direction The light becomes light with a highly collimated distribution 42 . In the case of a narrow field of view display, when light 42 with such a distribution is incident on the transparent and scattering switching element 22 in the transparent state, light with a highly collimated distribution of light distributed along the X direction is directly transmitted through the transparent and scattering switching element 22 , and emit light with distribution 42 . The light 42 having this distribution is transmitted through the liquid crystal panel 21 and is emitted to realize a narrow field of view display for the X direction.

In the third modification of the first exemplary embodiment, since the amount of light emitted from the backlight 13 and absorbed by the louver 12 can be reduced compared to the first exemplary embodiment, bright wide viewing angle display can be realized. Specifically, since the light amount of the backlight 13 is limited, the third modification is effective in the case where it is only necessary to realize switching of the viewing angle in the X direction. Except for the above, the components, operations, and effects of the third modification of the first exemplary embodiment are the same as those of the first exemplary embodiment.

Next, a second exemplary embodiment of the present invention will be explained. 11 is a cross-sectional view showing a liquid crystal display device according to a second exemplary embodiment of the present invention. In the first exemplary embodiment described above, as shown in FIG. 1 , one louver 12 in which band-shaped transparent regions 12 a and absorbing regions 12 b are alternately arranged is provided between the backlight 13 and the transparent and scattering switching member 22 . On the other hand, in the second exemplary embodiment, as shown in FIG. 11 , the louver 15 and the louver 14 are stacked so as to be disposed between the backlight 13 and the transparent and scattering switching member 22 . For the louver 15, the transparent regions 15a and the absorbing regions 15b are alternately arranged in one direction. For the louvers 14 , strip-shaped transparent regions 14 a and absorbing regions (not shown) are alternately arranged in a direction orthogonal to the direction in which the louvers 15 are arranged.

Therefore, in the second exemplary embodiment, the directivity of light incident on the louver 12 can be improved not only in one direction but also in a direction orthogonal thereto. Therefore, for example, narrow field of view display can be effectively realized not only in the horizontal direction but also in the vertical direction. Except for the above, the components, operations, and effects of the second exemplary embodiment are the same as those of the first exemplary embodiment.

Next, a third exemplary embodiment of the present invention will be explained. 12 is a sectional view showing a liquid crystal display device according to a third exemplary embodiment of the present invention. In the first exemplary embodiment described above, as shown in FIG. 1 , a conventional PDLC layer 11 in which liquid crystal molecules 11 b are uniformly dispersed in a polymer matrix 11 a is used as the planar transparent and scattering switching element 22 . On the other hand, in the third exemplary embodiment, as shown in FIG. 12 , a PDLC layer 16 modulated so that the distribution of liquid crystal molecules 16 b dispersed into a polymer matrix 16 a has annular unevenness is used. In the modulation PDLC layer 16, for example, a portion where the liquid crystal molecules 11b are dense and a portion where the liquid crystal molecules 11b are sparse are repeated cyclically in one direction. The modulation PDLC layer 16 strongly scatters incident light in a direction in which the portion where the liquid crystal molecules 11b are dense and the portion where the liquid crystal molecules 11b are sparse are repeated in a ring shape. Therefore, the viewing angle in this direction can be increased.

Such a modulated PDLC layer 16 can be manufactured by using the same material as a conventional PDLC layer for the PDLC layer, and exposing and photocuring the PDLC layer through a photomask. Before curing, light is irradiated onto the PDLC layer through a photomask in which a line pattern is formed circularly. The part irradiated by light starts to harden. At this time, a concentration gradient of liquid crystal molecules 16b occurs between the hardened area and the non-hardened area. After exposing the PDLC layer through a photomask for a predetermined time, the entire surface of the PDLC layer is exposed, whereby the modulated PDLC layer 16 is obtained. In this modulation of the PDLC layer 16, a mixture of two or more kinds of liquid crystal molecules having different sizes can be used as the liquid crystal molecules 16b. Except for the above, the components, operations, and effects of the third exemplary embodiment are the same as those of the first exemplary embodiment.

Next, a fourth exemplary embodiment of the present invention will be explained. 13 is a sectional view showing a liquid crystal display device according to a fourth exemplary embodiment of the present invention. In the fourth exemplary embodiment, as shown in FIG. 13, in addition to the structure of the liquid crystal display device according to the first exemplary embodiment, the liquid crystal display device further includes a light source light intensity control unit 26 and a transparent and scattering switching element control unit 27. . The light source light intensity control unit 26 controls the amount of current to be supplied to the white LED 25, and adjusts the amount of light (ie, the brightness of the white LED 25). The transparent and scattering switching element control unit 27 turns on and off the voltage of the transparent and scattering switching element 22 . A light source light intensity control unit 26 and a transparent and scattering switching element control unit 27 are constituted in association with each other. Except for the above, the components of the fourth exemplary embodiment are the same as those of the first exemplary embodiment.

Next, the operation of the liquid crystal display device according to the fourth exemplary embodiment constituted as above will be explained. As shown in FIG. 13 , in the case of wide-field display, the transparent and scattering switching element control unit 27 does not apply a voltage to the transparent and scattering switching element 22 . Thus, the light incident on the transparent and diffusing switching element 22 from the louver 12 is diffused. At this time, the light source light intensity control unit 26 supplies current to the white LED 25 so that the front brightness (ie, the brightness at the 0-degree viewing angle of the liquid crystal panel 21 ) takes a predetermined value. In the case of a narrow field of view display, the transparent and diffuse switching element control unit 27 applies a voltage to the transparent and diffuse switching element 22 . Thus, light incident on the transparent and diffusive switching element 22 from the louver 12 is directly transmitted through the transparent and diffusive switching element 22 . Therefore, when the amount of current supplied to the white LEDs 25 is the same (that is, the amount of light emitted from the backlight 13 is the same), the front of the liquid crystal panel 21 will be too bright. Therefore, the amount of current supplied to the white LED 25 is adjusted so that the front luminance of the liquid crystal panel 21 in the case of narrow viewing field display takes the same value as that in the case of wide viewing field display. Therefore, in the fourth exemplary embodiment, the front luminance of the liquid crystal panel 21 is kept constant. It should be noted that in the case where the white LED 25 is composed of a blue LED and a yellow phosphor, the light quantity of the white LED 25 can be adjusted by pulse width modulation of current. In the case of the white LED 25 composed of a blue LED and a yellow phosphor, the yellow phosphor is excited to emit yellow light by part of the blue light emitted from the blue LED, and the blue and yellow light are mixed to generate white light. When the amount of current is adjusted so that the front luminance of the liquid crystal panel 21 in the case of narrow field of view display takes an equivalent value to that in the case of wide field of view display, the liquid crystal panel 21 will be damaged due to fluctuations in the emissivity of blue light and yellow light. color change. On the other hand, when the light quantity is adjusted by pulse modulation, the light quantity adjustment is realized by adjusting the ratio of the light emission time, so that the chromaticity change of the liquid crystal panel 21 can be controlled. Except for the above, the operations and effects of the fourth exemplary embodiment are the same as those of the first exemplary embodiment.

Next, a fifth exemplary embodiment of the present invention will be explained. 14 is a sectional view showing a liquid crystal display device according to a fifth exemplary embodiment of the present invention. In the fourth embodiment described above, as shown in FIG. 13 , white LEDs 25 and line light sources 36 are used. On the other hand, in the fifth exemplary embodiment, as shown in FIG. 14 , a light source in which red LEDs 28 , green LEDs 29 and blue LEDs 30 are arranged linearly and circularly is used instead of line light source 36 . The liquid crystal display device includes a light source light intensity control unit 26 for controlling the amount of current to be supplied to the red LED 28 , green LED 29 and blue LED 30 and adjusting the amount of light (ie, the brightness of the LEDs). Except for the above, the components of the fifth exemplary embodiment are the same as those of the fourth exemplary embodiment.

Next, the operation of the liquid crystal display device according to the fifth exemplary embodiment constituted as above will be explained. As shown in FIG. 14 , the light emitted from the red LED 28 , the green LED 29 , and the blue LED 30 is incident on the backlight 13 . Red, green, and blue are the three primary colors of light, and the lights of these three colors overlap each other to form white light. The backlight 13 converts incident light into planar light. In the case of a wide field of view display, this light is incident on the transparent and scattering switching element 22 and is scattered. At this time, since the degree of scattering of light depends on the wavelength of light, light with a shorter wavelength is scattered more strongly, and light with a longer wavelength is scattered less. In other words, blue light is more easily scattered and red light is less scattered. Therefore, when the liquid crystal panel is viewed from the front, the display image appears reddish.

Thus, when light is diffused by transparent and diffusive switching element 22, for example, the amount of current supplied to blue LED 30 is increased to boost blue light which is more easily scattered, while the amount of current supplied to red LED 28 is decreased to fade out less Scattered red light. In this way, in the wide-field display and the narrow-field display, the intensity of the light emitted by the red LED 28, the green LED 29, and the blue LED 30 is adjusted in association with whether a voltage is applied to the transparent and scattering switching element 22, by This enables the color of the displayed image to remain constant when the liquid crystal panel is viewed from the front. Except for the above, the operations and effects of the fifth exemplary embodiment are the same as those of the fourth exemplary embodiment.

Next, a sixth exemplary embodiment of the present invention will be explained. 15 is a sectional view showing a liquid crystal display device according to a sixth exemplary embodiment of the present invention. In the sixth exemplary embodiment, in addition to the structure of the liquid crystal display device according to the first exemplary embodiment, transparent substrates 121 are provided on both sides of the shutter 12 . In one example, the material of the transparent substrate 121 is polyethylene terephthalate. Except for the above, components of the sixth exemplary embodiment are the same as those of the first exemplary embodiment.

In the liquid crystal display device according to the sixth exemplary embodiment constituted as above, since the transparent substrates 121 are provided on both sides of the louver 12, there is an effect that the resistance of the louver 12 to changes in temperature and humidity can be improved, thereby improving the liquid crystal display. Equipment reliability. Except for the above, the operations and effects of the sixth exemplary embodiment are the same as those of the first exemplary embodiment. Furthermore, the sixth exemplary embodiment can also be applied to the second to fifth exemplary embodiments.

Next, a seventh exemplary embodiment of the present invention will be explained. 16 is a sectional view showing a liquid crystal display device according to a seventh exemplary embodiment of the present invention. While in the sixth exemplary embodiment, the louver and the transparent and diffuse switching element are fixed with double-sided adhesive tape, in the seventh exemplary embodiment, the louver 12 having the transparent substrate 121 on both sides and the transparent and diffuse switching element 22 are bonded. , as a result, integrally formed. Except for the above, the components of the seventh exemplary embodiment are the same as those of the sixth exemplary embodiment.

In the liquid crystal display device according to the seventh exemplary embodiment constituted as above, transparent substrates 121 are provided on both sides of louver 12, and furthermore, louver 12 and transparent and scattering switching element 22 are integrally formed. Therefore, the resistance of the shutter 12 to changes in temperature and humidity can be improved, and the reliability of the liquid crystal display device can be improved. It is also possible to reduce the thickness of the liquid crystal display device. Except for the above, the operations and effects of the seventh exemplary embodiment are the same as those of the sixth exemplary embodiment.

Next, an eighth exemplary embodiment of the present invention will be explained. 17 is a sectional view showing a liquid crystal display device according to an eighth exemplary embodiment of the present invention. Compared with the structure of the liquid crystal display device according to the seventh exemplary embodiment, the eighth exemplary embodiment is characterized in that the louver 12 and the transparent and scattering switching element 22 are integrally formed and have a common substrate. In this example, the louver 12 has transparent substrates 121 on both sides thereof, and the substrate 121 of the louver 12 also serves as a transparent substrate on the side of the transparent and scattering switching element 22 . The transparent and diffuse switching element 22 therefore does not have a transparent substrate 9 on the side of the louver 12 . Except for the above, the components of the eighth exemplary embodiment are the same as those of the seventh exemplary embodiment.

As described above, in the liquid crystal display device according to the eighth exemplary embodiment, not only the reliability can be improved as in the liquid crystal display device according to the seventh exemplary embodiment, but also the thickness of the liquid crystal display device can be reduced. In addition, since the number of substrates constituting the liquid crystal display device can be reduced, the weight of the liquid crystal display device can also be reduced. Except for the above, the operations and effects of the eighth exemplary embodiment are the same as those of the seventh exemplary embodiment.

Next, a ninth exemplary embodiment of the present invention will be explained. 18 is a sectional view showing a liquid crystal display device according to a ninth exemplary embodiment of the present invention. Compared with the structure of the liquid crystal display device according to the eighth exemplary embodiment, in the ninth exemplary embodiment, the shutter 12 has only the transparent substrate 121 shared by the shutter 12 and the transparent and scattering switching element 22, and does not have 13 sides of the transparent substrate. Except for the above, components of the ninth exemplary embodiment are the same as those of the eighth exemplary embodiment.

In the liquid crystal display device according to the ninth exemplary embodiment constituted as above, since the transparent substrate on the backlight 13 side of the louver 12 is not provided, the reliability is lower than that of the liquid crystal display device according to the eighth exemplary embodiment. However, since the transparent substrate 121 is provided on the transparent and scattering switching element 22 side, reliability can be improved compared to the first exemplary embodiment. Furthermore, in the ninth exemplary embodiment, since the transparent substrate of the louver 12 can be eliminated, the thickness and weight of the liquid crystal display device can be further reduced compared to the liquid crystal display device according to the eighth exemplary embodiment. Except for the above, the operations and effects of the ninth exemplary embodiment are the same as those of the eighth exemplary embodiment.

Next, a tenth exemplary embodiment of the present invention will be explained. 19 is a sectional view showing a liquid crystal display device according to a tenth exemplary embodiment of the present invention. Compared with the structure of the liquid crystal display device according to the first exemplary embodiment, the liquid crystal display device according to the tenth exemplary embodiment is different in that the liquid crystal display device described in the monthly "Display", May 2004, pages 14 to 17 The highly collimated backlight 213 described in . In this conventional highly collimated backlight 213, LEDs are placed in the positions where the light guide plate is placed, and linear microprisms are placed in the light guide plate centered on the LEDs. A prism sheet in which the prism structure is likewise arranged centered on the LED is arranged on the light-emitting surface of the light guide plate. In addition, a reflective sheet is provided on the surface on the opposite side to the surface of the light guide plate on which the prism sheet is provided. Except for the above, the components of the tenth exemplary embodiment are the same as those of the first exemplary embodiment.

In the liquid crystal display device according to the tenth exemplary embodiment constituted as above, since the highly collimated backlight 213 whose directivity is two-dimensionally improved on its light emitting surface is used, the absorption loss of light by the louvers 12 can be reduced, and realize is displayed brightly. In addition, since the directivity of the backlight is two-dimensional, it is also possible to exhibit the effect of switching the viewing angle for the direction perpendicular to the direction in which the transparent regions and absorbing regions of the louver 12 are alternately arranged. It should be noted that highly collimated backlights suitable for use in this exemplary embodiment are not limited to the highly collimated backlights described in the monthly "Display", May 2004, pages 14-17, as long as the two-dimensional By improving its directivity, any backlight can be applied to liquid crystal display devices.

20 is a graph showing experimental results of applying a slight voltage to the transparent and scattering switching element 22 in a scattering state to adjust scattering properties in the liquid crystal display device according to the tenth exemplary embodiment. In this graph, the horizontal axis represents the angle of view, and the vertical axis represents luminance. The results indicated by the dashed lines are the luminance distributions when no voltage is applied to the PDLC layer constituting the transparent and scattering switching elements, and the results indicated by the solid lines are when some voltage (in one example, 1 volt) is applied to the Brightness distribution when on PDLC layer. It should be noted that in this context, a little voltage means a small voltage compared to the voltage that brings the transparent and scattering switching elements into the transparent state. Although the front luminance (luminance in the 0° direction) was 75 cd/m ² with no voltage applied to the PDLC layer, the front luminance increased to 120 cd/m ² with some voltage applied thereto. On the other hand, in the oblique direction, more specifically, in the range from +25° to +80° or in the range from -25° to -80°, although the luminance drops when a little voltage is applied thereto , but the degree of voltage drop is very small, ensuring substantially the same level of brightness as when no voltage is applied. This shows that by applying a small voltage while the scattering is performed by the transparent and scattering switching elements, slightly reducing the scattering properties, it is possible to significantly increase the brightness in the front without significantly reducing the brightness in the oblique direction. This result is valid where the front brightness falls into a wide-field display due to the limited amount of light from the backlight. Although the tenth exemplary embodiment has been explained, the above explanation is not limited to the tenth exemplary embodiment, but can also be applied to other exemplary embodiments. Except for the above, the operation and effects of the tenth exemplary embodiment are the same as those of the first exemplary embodiment.

Next, an eleventh exemplary embodiment of the present invention will be explained. FIG. 21 is a perspective view showing a portable terminal device mounted with a liquid crystal display device of the present invention. As shown in FIG. 21, the liquid crystal display device 100 of the present invention is mounted on, for example, a cellular phone 90 or the like.

The liquid crystal display device of the present invention can be applied to portable devices such as cellular phones, making it possible to realize display switching the angle of view. Specifically, in the case where the liquid crystal display device of the present invention is mounted on a cellular phone, at least in the lateral direction of the cellular phone, transparent regions and absorbing regions of louvers serving as beam direction adjusting members are alternately arranged, thereby making it possible to Landscape of the phone, toggles between wide and narrow field of view displays. This prevents others from viewing sideways in places such as public transport facilities. It should be noted that portable devices are not limited to cellular phones, and liquid crystal display devices can be applied to various portable terminal devices such as personal digital assistants (PDAs), game machines, digital cameras, digital video cameras, and notebook computers. In addition, a portable device mounted with the liquid crystal display device of the present invention can have settings for changing the number of light sources independently of each other at the time of wide-field display and narrow-field display, and can set the light emission of the light source in both cases. Rate. Therefore, the user can set the optimum angle of view according to the usage environment. Furthermore, the portable terminal may have means for detecting the remaining battery power, and have control means capable of automatically changing the viewing angle according to the detected remaining battery power. As described above, in the liquid crystal display device of the present invention, since the electric power can be reduced more during the narrow viewing field than the wide viewing field display, it is possible to automatically change the wide viewing field display to the display when the remaining battery power is low. Reduce power consumption for narrow field of view displays and extend the operating time of portable devices.

Next, a twelfth embodiment of the present invention will be explained. 22 is a plan view showing a transparent and scattering switching element 22 of a liquid crystal display device according to a twelfth exemplary embodiment of the present invention. Compared with the structure of the first exemplary embodiment, the twelfth exemplary embodiment is different in that at least one side of the electrode 10 of the transparent and scattering switching element 22 is processed into a line shape. Except for the above, the components of the twelfth exemplary embodiment are the same as those of the first exemplary embodiment.

In the liquid crystal display device according to the twelfth exemplary embodiment constituted as above, by applying different voltages to the electrodes 10 of the transparent and scattering switching elements 22 processed into a line shape, switching of transparency and scattering can be locally performed in a plane . Therefore, for example, according to the image information to be displayed on the liquid crystal display device, only for the portion displaying secret information, the transparent and scattering switching element 22 can be made transparent to realize a narrow field of view display. It should be noted that the shape of the electrode 10 of the transparent and scattering switching element 22 is not limited to a linear shape, and may also be a block shape.

Therefore, it is possible to switch between narrow field of view display and wide field of view display in block form. In addition, in the two transparent substrates provided above and below the PDLC layer, the electrodes can be respectively processed into a line shape and arranged so that their longitudinal directions are perpendicular to each other. This enables passive matrix driving of the transparent and diffuse switching elements 22 and enables switching of the viewing angle of any part on the screen. Except for the above, the operations and effects of the twelfth exemplary embodiment are the same as those of the first exemplary embodiment.

It should be noted that, as the PDLC layer used in each exemplary embodiment and each modification, the PDLC layer is in a scattering state when no voltage is applied thereto and is in a transparent state when a voltage is applied thereto. Thus, the transparent and diffusive switching element consumes no electrical power when it is in a state in which the transparent and diffusive switching element scatters incident light. Therefore, since the power is distributed to the backlight power supply, the brightness of the light source in the diffuse state can be increased. However, the form of the PDLC layer is not limited thereto, and a PDLC layer that is in a transparent state when no voltage is applied thereto and that is in a scattering state when a voltage is applied thereto may also be used. Such a PDLC layer is obtained by exposing a material to harden it while applying a voltage thereto. Therefore, in the portable information terminal, it is not necessary to apply a voltage to the PDLC layer, and it is possible to control power consumption in a frequently used narrow field of view display.

In addition, cholesteric liquid crystals, ferroelectric liquid crystals, and the like can be used as liquid crystal molecules in the PDLC layer. Even if the applied voltage is turned off, the liquid crystal maintains the orientation state when the voltage is applied thereto, and has memory properties. By using such a PDLC layer, power consumption can be reduced.

As shown in FIG. 23 , the direction in which the transparent regions and the absorbing regions of the beam direction adjusting element are alternately formed may not be parallel to the pixel arrangement direction of the liquid crystal display panel. Therefore, it is possible to reduce the streaks formed due to the beam direction adjusting member and the display panel, and improve the image quality of the liquid crystal display device.

The display panel used in combination with the light source of the present invention is not limited to a transparent liquid crystal panel. Any display panel can be used as long as the display panel uses a backlight. Specifically, a liquid crystal panel that is less dependent on the viewing angle can be suitably used. As examples of the mode of such a liquid crystal panel, in the transverse electric field mode, there are IPS (In-Plane Switching) system, FFS (Frozen Field Switching) system, AFFS (Advanced Fringed Field Switching) system, and the like. In addition, in vertical alignment mode, there are MVA (Multi-domain Vertical Alignment) system, PVA (Pattern Vertical Alignment) system, ASV (Advanced Super V) system, etc., in which the liquid crystal panel is divided into regions to reduce alignment. Dependence on field of view angle. The present invention can also be suitably used in a film-compensated TN-mode liquid crystal display panel. By using these less field-of-view dependent liquid crystal panels, it is possible to control the hue change of the display and improve visibility when the transparent and scattering switching elements are in the scattering state. In addition, the liquid crystal panel is not limited to the transmissive liquid crystal panel, and any panel may be used as long as the panel has a transmissive area in each pixel. Semi-transmissive liquid crystal panels, micro-transmissive liquid crystal panels, and micro-reflective liquid crystal panels, which have a reflective area in a part of each pixel, can also be used. It should be noted that in order to reduce the dependence on the viewing angle, the reflective area is not always required, only the transmissive area can also reduce the dependence on the viewing angle.

The foregoing description of the embodiments is provided to enable any person of ordinary skill in the art to make and use the invention. Moreover, various modifications to these embodiments will be apparent to those skilled in the art, and the generic principles and specific examples defined herein may be applied to other embodiments without inventive effort. Thus, the intention is not to limit the invention to the embodiments described herein, but to be accorded the widest scope limited by the claims and their equivalents.

Furthermore, it should be noted that even if, during prosecution, the claims are amended, it is the inventor's intent to limit all equivalents of the claimed invention.

Claims (13)

1. A light source, comprising: backlight; A light beam direction adjustment element, which adjusts the direction of light incident from the backlight, and emits the light, wherein a transparent area for transmitting light and an absorption area for absorbing light are alternately formed along a direction perpendicular to the light adjustment direction. is a direction perpendicular to the surface of the beam direction adjusting element, the transparent area being provided in a matrix having a plurality of rows and columns; and The transparent and scattering switching element receives the incident light emitted from the beam direction adjusting element, and switches the incident light into a transmitted state and a scattered state; Wherein, in the light beam direction adjustment element, when the light beam direction adjustment element is viewed from the light adjustment direction, transparent regions are provided in a matrix shape. 2. The light source according to claim 1, wherein when the transparent region is viewed from the light adjustment direction, the shape of the transparent region is circular, elliptical, square or rectangular. 3. A light source, comprising: backlight; The light beam direction adjustment element adjusts the direction of light incident from the backlight and emits the light, wherein a transparent area for transmitting light and an absorption area for absorbing light are alternately formed along a direction perpendicular to its light adjustment direction, and the light adjustment the direction is a direction perpendicular to the surface of the beam direction adjusting element; and The transparent and scattering switching element receives the incident light emitted from the beam direction adjusting element, and switches the incident light into a transmitted state and a scattered state; Wherein, the transparent and scattering switching element and the light beam direction adjusting element are integrally formed. 4. A light source as claimed in claim 3, characterized in that the transparent and diffuse switching element and the beam direction adjusting element have a common substrate. 5. The light source according to claim 4, characterized in that the substrate of the beam direction adjusting element comprises a substrate shared only by the beam direction adjusting element and the transparent and diffuse switching element. 6. A display device comprising: Backlight, emitting flat light; A light beam direction adjustment element, which adjusts the direction of light incident from the backlight, and emits the light, wherein a transparent area for transmitting light and an absorption area for absorbing light are alternately formed along a direction perpendicular to the light adjustment direction. is a direction perpendicular to the surface of the beam direction adjusting element, the transparent area being provided in a matrix with a plurality of rows and columns; a transparent and scattering switching element capable of switching the light incident from the beam direction adjusting element to transmit said light and to scatter said light; and Liquid crystal panels that use light incident from transparent and diffuse switching elements to display images, Wherein, in the light beam direction adjustment element, when the light beam direction adjustment element is viewed from the light adjustment direction, transparent regions are provided in a matrix shape. 7. The display device according to claim 6, wherein the shape of the transparent area is circular, elliptical, square or rectangular when viewed from the light adjustment direction. 8. A display device comprising: Backlight, emitting flat light; The light beam direction adjustment element adjusts the direction of light incident from the backlight and emits the light, wherein a transparent area for transmitting light and an absorption area for absorbing light are alternately formed along a direction perpendicular to its light adjustment direction, and the light adjustment The direction is the direction perpendicular to the surface of the beam direction adjusting element; a transparent and scattering switching element capable of switching the light incident from the beam direction adjusting element to transmit said light and to scatter said light; and Liquid crystal panels that use light incident from transparent and diffuse switching elements to display images, Wherein, the direction in which the transparent region and the absorbing region of the light beam direction adjusting member are alternately formed and the pixel arrangement direction of the display panel are not parallel to each other. 9. A portable terminal device, comprising: light source; adjustment means capable of varying the amount of backlight and the transparent and diffuse state of the transparent and diffuse switching element independently of each other; Electric energy accumulation device; detection means for the residual amount of electric energy accumulated in the electric energy accumulating means; and a control device that automatically changes the amount of backlight, and the transparent and diffuse state of the transparent and diffuse switching element according to the detected residual amount information, The light sources include: backlight; The light beam direction adjustment element adjusts the direction of light incident from the backlight and emits the light, wherein a transparent area for transmitting light and an absorption area for absorbing light are alternately formed along a direction perpendicular to its light adjustment direction, and the light adjustment the direction is a direction perpendicular to the surface of the beam direction adjusting element; and The transparent and scattering switching element receives the incident light emitted from the beam direction adjusting element, and switches the incident light into a transmitted state and a scattered state. 10. A portable terminal device comprising a light source, the light source comprising: backlight; The light beam direction adjustment element adjusts the direction of light incident from the backlight and emits the light, wherein a transparent area for transmitting light and an absorption area for absorbing light are alternately formed along a direction perpendicular to its light adjustment direction, and the light adjustment the direction is a direction perpendicular to the surface of the beam direction adjusting element; and The transparent and scattering switching element receives the incident light emitted from the beam direction adjusting element, and switches the incident light into a transmitted state and a scattered state; Wherein, the transparent area and the absorbing area of the transparent and scattering switching element are alternately formed along the lateral direction of the portable terminal device. 11. A beam direction switching element, wherein integrally formed: a beam direction adjusting element and a transparent and scattering switching element that adjusts the direction of incident light and emits the light; and a transparent and scattering switching element , switching the light incident from the beam direction adjustment element, so as to transmit the light and scatter the light. 12. The beam direction switching element according to claim 11, characterized in that the transparent and scattering switching element and the beam direction adjusting element are formed on a common substrate. 13. The beam direction switching element according to claim 12, wherein the substrate of the beam direction adjusting element comprises a substrate shared only by the beam direction adjusting element and the transparent and diffuse switching element.

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