JP2009086026A - Electro-optical device and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electro-optical device having a small-sized illumination means even when the device is a time-sharing type and the luminance is increased, and to provide electronic equipment having the device. <P>SOLUTION: The electro-optical device includes a liquid crystal panel displaying an image in an image display region, a backlight unit 3 capable of illuminating the liquid crystal panel with illumination light in a plurality of colors, and a control means. The image display region is divided into a plurality of image division regions. The backlight unit 3 includes: a light guide plate 21 that is divided into light guide division regions 21A, 21B corresponding to the respective image division regions and is provided with a reflection film 25 in the boundary part between the light guide division regions 21A, 21B; and light sources 22, 23 emitting illumination light to the respective light guide division regions 21A, 21B. The control means supplies sequential image signals to each of the plurality of image division regions, controls not to drive the light source 22 or 23 disposed in the light guide division region corresponding to the image division region where the image signal is being supplied, as well as controls to drive the other light source 22 or 23. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electro-optical device such as a liquid crystal device and an electronic apparatus including the same.

When performing color display in a liquid crystal device, there are the following two types. One is a space division type in which a liquid crystal panel including a color filter is used and one pixel is formed by three sub-pixels of R (red), G (green), and B (blue). The other is a time-division type in which R, G, and B color lights are temporally separated from a light source, and driving (color sequential display) according to the color of light is performed on a liquid crystal panel.
Here, the space division type liquid crystal device requires three times the spatial resolution in order to display an image having the same resolution as compared with the case of performing monochrome display. On the other hand, in the time division type liquid crystal device, the same resolution as in the case of performing monochrome display may be used, so that it is easy to increase the definition of the image.

  However, the time-division type liquid crystal device also has a problem that the luminance decreases as the number of pixels increases, because the time for writing image signals to all pixels becomes longer. In other words, in a time-division type liquid crystal device, after writing a red image signal to all pixels, irradiate red illumination light, and after writing a green image signal to all pixels, irradiate green illumination light, After the blue image signal is written to the blue light, the blue illumination light is irradiated. For this reason, for example, when driving at 60 Hz, it is necessary to irradiate illumination light from signal writing at about 5.5 msec for each color. Therefore, in the case of SVGA (Super VGA: 800 × 600 pixels), the time required to write the image signal to all the pixels is about 5.25 msec, and therefore the illumination light irradiation time is about 0.25 msec. The brightness of is reduced.

Here, in a liquid crystal device that directly emits illumination light from a light source, the image display area is divided into a plurality of divided areas, and a plurality of light sources capable of emitting RGB three colors of illumination light are provided corresponding to each of the plurality of divided areas. Have been proposed (see, for example, Patent Document 1). In this liquid crystal device, after supplying an image signal to one divided region, illumination light is irradiated from a corresponding light source, thereby increasing the light source lighting duty ratio and improving the luminance of the image.
Japanese Patent Laid-Open No. 5-80716

  However, the following problems remain in the conventional liquid crystal device. That is, for example, when the liquid crystal panel is miniaturized like a display in a mobile phone, if a light source such as an LED element is arranged corresponding to each pixel, there is a problem that the illumination means becomes large.

  The present invention has been made in view of the above-described conventional problems, and provides a time-division type electro-optical device including a miniaturized illumination unit and an electronic apparatus including the same even if the luminance is improved. With the goal.

  The present invention employs the following configuration in order to solve the above problems. That is, an electro-optical device according to the present invention includes an electro-optical panel that displays an image in an image display area in accordance with a supplied image signal, and an illuminating unit that can irradiate a plurality of colors of illumination light toward the electro-optical panel. And a control means for controlling the supply of the image signal to the electro-optical panel and the driving of the light source, the image display area is divided into a plurality of image division areas, and the illumination means includes the plurality of illumination means. A light guide plate that is divided into a plurality of light guide divided regions corresponding to each of the image divided regions and is provided with a light shielding film at a boundary between two adjacent light guide divided regions, and each of the plurality of light guide divided regions A plurality of light sources that emit the illumination light toward the screen, and the control means sequentially supplies the image signals to each of the plurality of image division areas, and the image division areas in which the image signals are being supplied. The light source provided in the light guiding division regions corresponding to the addition to the non-driven, characterized in that driving the other light source.

In this invention, the light guide plate is divided into a plurality of light guide divided areas, and a light source is provided corresponding to each of the light guide plates, so that illumination light is irradiated directly from the light source to each of the plurality of image divided areas. Can be made thinner.
That is, even if the irradiable range of the light source is narrow, the light emitted from the light source can be irradiated over a wide range via the light guide plate. Thereby, since it is not necessary to arrange a large number of light sources in order to irradiate the entire area with respect to one image division area, the number of light sources installed in one image division area can be reduced. Therefore, the illumination means can be thinned.
Here, since a light-shielding film is provided at the boundary between the light guide division regions, light guided in one light guide division region is prevented from entering another light guide division region adjacent thereto. it can.

In the electro-optical device according to the aspect of the invention, it is preferable that the light shielding film is a reflective film that reflects the illumination light.
In this invention, by providing a reflective film at the boundary portion of the light guide division region, the light traveling toward the boundary portion can be reflected and effectively used as illumination light.

In the electro-optical device according to the aspect of the invention, the control unit may sequentially supply the image signal for each column along one direction of the image display region, and the plurality of image division regions may extend along the one direction. Are preferably arranged.
In this invention, by arranging the image division regions along one direction in which the image signal is written for each column, when sequentially writing the image signals to each of the plurality of image division regions, the image signal to each pixel region is written. Control of writing becomes easy.

In the electro-optical device according to the aspect of the invention, each of the plurality of light sources may include a plurality of light emitting members that emit light of the plurality of colors.
In this invention, the light of each color irradiated from each light emitting member is irradiated from the light guide divided region to the image divided region.

According to another aspect of the invention, there is provided an electronic apparatus including the above-described electro-optical device.
In the present invention, as described above, since the illumination means is thinned, the entire device can be miniaturized.

  Hereinafter, an embodiment of an optical element in the present invention will be described with reference to the drawings. In each drawing used in the following description, the scale is appropriately changed to make each member a recognizable size. Here, FIG. 1 is a schematic cross-sectional view showing a liquid crystal device, FIG. 2 is a plan view showing an image display region, and FIG. 3 is a plan view showing illumination means.

[Liquid crystal device]
The liquid crystal device (electro-optical device) 1 in the present embodiment is a transmissive color liquid crystal device. Here, the display area which is the minimum unit constituting the display is referred to as a “sub-pixel area”.
As shown in FIG. 1, the liquid crystal device 1 includes a liquid crystal panel 2, a backlight unit (illuminating means) 3 that irradiates the liquid crystal panel 2 with illumination light, and a control means 4.
The liquid crystal panel 2 includes an element substrate 11, a counter substrate 12 disposed to face the element substrate 11, and a liquid crystal layer 13 disposed between the element substrate 11 and the counter substrate 12.
In the liquid crystal panel 2, the element substrate 11 and the counter substrate 12 are bonded together with a sealing material 14, and the liquid crystal layer 13 is sealed between the element substrate 11 and the counter substrate 12 by the sealing material 14. . Here, an area surrounded by the sealing material 14 in the liquid crystal panel 2 is an image display area 15 shown in FIG.

In addition, a plurality of pixel regions 16 are arranged in the image display region 15 of the liquid crystal panel 2. The plurality of pixel regions 16 are arranged along the horizontal scanning direction H and the vertical scanning direction (one direction) V, respectively, and are arranged in a matrix as a whole.
The image display area 15 is divided into two image division areas 15A and 15B. The two image division areas 15 </ b> A and 15 </ b> B are arranged along the vertical scanning direction V in the image display area 15. In other words, the image display area 15 has an upper image division area 15A along the vertical scanning direction V and a lower image division area 15B.

As shown in FIG. 1, the element substrate 11 has a substantially rectangular shape in a plan view and uses a glass substrate as a base. Various metal films, insulating films, semiconductor layers, impurity layers, and the like are formed on the glass substrate. ing. The element substrate 11 includes a pixel portion including a pixel electrode, a thin film transistor (TFT), a storage capacitor, and the like formed on the glass substrate using a predetermined method such as a photolithography technique or an inkjet method, And a wiring portion for supplying an electric signal or the like to the pixel. Further, an alignment film for controlling the alignment of liquid crystal molecules constituting the liquid crystal layer 13 is formed on the inner surface of the element substrate 11 (the surface on the liquid crystal layer 13 side).
A polarizing plate 17 is disposed on the outer surface of the element substrate 11 (on the side away from the liquid crystal layer 13).

Similar to the element substrate 11, the counter substrate 12 has a substantially rectangular shape in plan view and has a glass substrate as a base, and a black matrix, a color filter layer, a protective film, an electrode, and the like are formed on the glass substrate. . An alignment film is formed on the inner surface of the counter substrate 12. This alignment film is formed so that the alignment direction of the liquid crystal molecules is orthogonal to the alignment direction of the alignment film formed on the element substrate 11.
In addition, a polarizing plate 18 is disposed on the outer surface side of the counter substrate 12 as in the case of the element substrate 11.

The backlight unit 3 is disposed on the outer surface side of the element substrate 11. 1 and 3, the backlight unit 3 reflects the light guide plate 21, the light sources 22 and 23 that emit illumination light toward the light guide plate 21, and the illumination light toward the light guide plate 21. The reflecting plate 24 is provided.
As shown in FIG. 3, the light guide plate 21 is divided into two light guide divided regions 21A and 21B, which are the same number as the image divided regions 15A and 15B. The two light guide divided areas 21A and 21B are arranged along the vertical scanning direction V of the image display area 15 in the same manner as the image divided areas 15A and 15B.
That is, the light guide plate 21 has an upper light guide division region 21A along the vertical scanning direction V and a lower light guide division region 21B. Each of the light guide division regions 21A and 21B has a substantially rectangular shape in plan view. The light guide plate 21 has a reflective film (light shielding film) 25 provided at the boundary between the light guide divided regions 21A and 21B. The light guide plate 21 is formed by bonding each of the two divided light guide divided regions 21A and 21B via the reflective film 25.

The light source 22 is provided corresponding to the light guide division region 21A. And the light source 22 is provided in the center part of the edge along the major axis direction of 21 A of light guide division areas. Thus, by arranging the light source 22 at the center of the edge along the major axis direction of the light guide division region 21A, the light emitted from the light source 22 is guided to the entire area of the light guide division region 21A in a short time. Can do.
The light source 23 is provided corresponding to the light guide division region 21B. And the light source 23 is provided in the center part of the end surface in alignment with the major axis direction of the light guide division area 21B similarly to the above-mentioned. Thus, by arranging the light source 23 at the center of the edge along the major axis direction of the light guide division region 21B, the light emitted from the light source 23 can be quickly emitted from the light source 23 in the entire area of the light guide division region 21B as described above. Can be guided.
Each of the light sources 22 and 23 includes LED elements (light emitting members) 26A to 26C and LED elements (light emitting members) 27A to 27C that emit red light, green light, and blue light, respectively.

The control means 4 is configured to control the supply of image signals and scanning signals to the image display area 15 in the liquid crystal panel 2 and the drive of the light sources 22 and 23. The control unit 4 is arranged at the left end of the pixel region 16 in one column with respect to the pixel region 16 at the upper end in the vertical scanning direction V among the plurality of columns of pixel regions 16 arranged along the horizontal scanning direction H. The image signal is sequentially supplied from the pixel area 16 toward the pixel area 16 arranged at the right end.
Then, after supplying the image signal to all the pixel regions 16 in the row, the control unit 4 sequentially starts from the other pixel region 16 adjacent in the vertical scanning direction V for each column along the vertical scanning direction V. Similarly, an image signal is supplied.
Further, the control unit 4 is configured to control driving and non-driving of the LED elements 26A to 26C and 27A to 27C in accordance with the supply of the image signal. The details of the control of the image signal supply and the driving of the light sources 22 and 23 by the control means 4 will be described later.

[Driving method of liquid crystal device]
Next, a method for driving the liquid crystal device 1 having the above-described configuration will be described with reference to FIGS. Here, FIG. 4 is a timing chart showing image signal supply and driving of the light sources 22 and 23, and FIG. 5 is an explanatory diagram showing the display state of each image division area in each period of FIG.
First, the control means 4 writes red image information to each pixel area 16 in the upper image division area 15A in the image display area 15 (period A shown in FIG. 4 and FIG. 5A).
That is, the control unit 4 firstly arranges the pixels arranged at the left end in the horizontal scanning direction H with respect to the pixel region 16 arranged in the horizontal scanning direction H at the upper end in the vertical scanning direction V of the image display region 15. Red image signals are supplied in order along the horizontal scanning direction H from the region 16 toward the pixel region 16 arranged at the right end. The pixel region 16 to which the image signal is supplied generates an electric field having an intensity corresponding to the image signal supplied between the pair of electrodes, and changes the alignment direction of the liquid crystal layer 13 in the pixel region 16.
Then, the control means 4 supplies the red image signal to all the pixel regions 16 in one column at the upper end in the vertical scanning direction V, and then the other one column adjacent to the one pixel region 16 in the vertical scanning direction V. A red image signal is supplied to each of the pixel regions 16.
In this way, the control unit 4 supplies the red image signal to each of the plurality of columns of pixel regions 16 arranged along the vertical scanning direction V. Thereby, a red image signal is supplied to all the pixel areas 16 in the upper image division area 15A in the image display area 15.

Next, the control means 4 drives the LED element 26A in the light source 22 to irradiate the upper image division area 15A with red illumination light. Similarly to the above, the control means 4 supplies a red image signal to each pixel area 16 in the lower image division area 15B in the image display area 15 (period B shown in FIG. 4 and FIG. 5). (B)).
That is, the control means 4 drives the LED element 26A in the light source 22 provided corresponding to the upper image division region 15A to which the red image signal has already been supplied. The LED element 26 </ b> A emits red light to the upper light guide division region 21 </ b> A in the light guide plate 21. The red light is guided in the light guide divided area 21A and emitted toward the upper image divided area 15A.
Thereby, the red image written in the image division area 15A is displayed. At this time, since the reflective film 25 is provided between the upper light guide division region 21A and the lower light guide division region 21B in the light guide plate 21, the red light guides the upper light guide division region 21A. Light is prevented from entering the light guide division region 21B.
Further, the control means 4 supplies the red image signal to each pixel area 16 in the lower image division area 15B in the same manner as described above, following the supply of the image signal to each pixel area 16 in the image division area 15A. To do.

Subsequently, similarly to the above, the control unit 4 drives the LED element 27A in the light source 23 to irradiate the lower image division region 15B with red illumination light (period C and diagram shown in FIG. 4). 5 (c)). Thereby, the red image written in the image division area 15B is displayed. At this time, the reflective film 25 provided on the light guide plate 21 prevents red light that is guided through the lower light guide division region 21B from entering the light guide division region 21A.
Then, the control means 4 drives each of the LED element 26A in the light source 22 and the LED element 27A in the light source 23 until the green image signal is supplied to each pixel area 16, and the red written in each of the image division areas 15A and 15B. Display the image.

Next, the control unit 4 stops driving the LED element 26A in the light source 22, and supplies a green image signal to each pixel region 16 in the upper image division region 15A. Further, the control means 4 maintains the driving state of the LED element 27A in the light source 23 (period D shown in FIG. 4 and FIG. 5 (d)).
That is, the control means 4 does not drive the LED element 26A in the light source 22 in order to supply a red image signal to each pixel area 16 in the upper image division area 15A. And the control means 4 supplies a green image signal with respect to each pixel area | region 16 in 15 A of upper image division areas similarly to the above-mentioned.
Further, the control means 4 brings the LED element 27A in the light source 23 into a driving state, and continues the red image display in the lower image division region 15B.

Next, the control means 4 drives the LED element 26B in the light source 22, and irradiates the upper image division area 15A with green illumination light. Moreover, the control means 4 stops the drive of LED element 27A in the light source 23 similarly to the above-mentioned. Then, the control means 4 supplies a green image signal to each pixel area 16 in the lower image division area 15B following the supply of the image signal to each pixel area 16 in the image division area 15A (FIG. 4 and period (E) shown in FIG.
Subsequently, similarly to the above, the control unit 4 drives the LED element 27B in the light source 23 and irradiates the lower image division region 15B with green illumination light (period F and FIG. 4 shown in FIG. 4). 5 (f)). Thereby, the green image written in the image division area 15B is displayed. Then, the control unit 4 displays the green image written in each of the image division regions 15A and 15B until the blue image signal is supplied to each pixel region 16.

Next, similarly to the above, the control unit 4 stops driving the LED element 26B in the light source 22, and supplies a blue image signal to each pixel region 16 in the upper image division region 15A. Further, the control means 4 maintains the driving state of the LED element 27B in the light source 23 (period G shown in FIG. 4 and FIG. 5 (g)).
Subsequently, the control unit 4 drives the LED element 26 </ b> C in the light source 22 to irradiate the upper image division region 15 </ b> A with blue illumination light. Moreover, the control means 4 stops the drive of LED element 27B in the light source 23 similarly to the above-mentioned. Then, the control means 4 supplies a blue image signal to each pixel area 16 in the lower image division area 15B following the supply of the image signal to each pixel area 16 in the image division area 15A (FIG. Period H shown in FIG. 4 and FIG.
Further, similarly to the above, the control unit 4 drives the LED element 27C in the light source 23 to irradiate the lower image division region 15B with blue illumination light. Then, the control means 4 displays the green image written in each of the image division regions 15A and 15B until the supply of the red image signal to each pixel region 16 (period I shown in FIG. 4 and FIG. 5 (i)). ).

Next, similarly to the above, the control unit 4 stops driving the LED element 26C in the light source 22, and supplies a red image signal to each pixel region 16 in the upper image division region 15A. To do. Further, the control means 4 maintains the driving state of the LED element 27C in the light source 23 (period J shown in FIG. 4 and FIG. 5 (j)). Thereafter, the control means 4 displays the images of the respective colors in the image display area 15 in the order of red, green, and blue in the same manner as described above.
That is, the control unit 4 drives the corresponding light source 22 from the time when the image signal of one color is supplied to the image division area 15A until the image signal of another color is supplied. Similarly, the control unit 4 drives the corresponding light source 23 until the image signal of one color is supplied after the image signal of one color is supplied to the image division region 15B. Accordingly, since the light source 22 is driven even during the supply of the image signal to the image division region 15B, the image division is performed as compared with the case where the illumination signal is irradiated after the image signal is supplied to the entire image display region 15. The irradiation time of the illumination light to the region 15A can be lengthened. The same applies to the image division amount 15B.
As described above, the liquid crystal device 1 repeats the periods B to J shown in FIG. 4 and also repeats the states shown in FIGS. 5B to 5J, so that images of red, green, and blue colors are sequentially displayed. Is displayed.

〔Electronics〕
The liquid crystal device 1 described above is used as a display unit 101 of a mobile phone (electronic device) 100 as shown in FIG. Here, FIG. 6 is a perspective view showing the mobile phone.
The cellular phone 100 includes a display unit 101, a plurality of operation buttons 102, an earpiece 103, a mouthpiece 104, and a main body unit including the display unit 101.

According to the liquid crystal device 1 and the mobile phone 100 configured as described above, the backlight unit 3 is provided by dividing the light guide plate 21 into two light guide divided regions 21A and 21B and providing the light sources 22 and 23 respectively. It can be thin. Therefore, the liquid crystal device 1 can be downsized.
Here, the light guided through each of the light guide divided areas 21A and 21B is incident on the other light guide divided areas 21A and 21B by the reflection film provided at the boundary between the light guide divided areas 21A and 21B. Can be prevented. Furthermore, the light guided through the respective light guide divided regions 21A and 21B by the reflective film 25 can be effectively used.

In addition, this invention is not limited to the said embodiment, A various change can be added in the range which does not deviate from the meaning of this invention.
For example, the image display area is divided into two image division areas and the light guide plate is divided into two light guide division areas. However, the image display area is not limited to two and may be divided into three or more. At this time, as described above, the control unit stops driving the light source provided in one light guide divided region corresponding to one image divided region in which an image signal is being written, and is also writing an image signal. A plurality of light sources provided in each of the plurality of other light guide divided regions corresponding to each of the other image divided regions that are not are driven. As described above, by increasing the number of divisions, the illumination light irradiation time can be extended with respect to the writing period of the image signal to all the pixel regions. Therefore, the brightness of the image can be further increased.

Further, although the image division regions are arranged along the vertical scanning direction, other arrangements may be used as long as the control unit sequentially supplies image signals to each of the plurality of image division regions. The same applies to the light guide division region.
And although the reflective film is provided in the boundary part of a light guide division area, the light which guides in one light guide division area in two adjacent light guide division areas enters into the other light guide division area As long as it can be prevented, a light shielding film other than the reflective film may be used.
Furthermore, although a liquid crystal panel is used as the electro-optical panel, other electro-optical panels such as a panel using an electrophoretic element may be used as long as the electro-optical panel displays an image by transmitting the illumination light irradiated from the back by the illumination unit. An electro-optical panel may be used.

It is a schematic sectional drawing which shows the liquid crystal device of this invention. It is a top view which shows the structure of an image display area. It is a top view which shows an illumination means. It is a timing chart which shows supply of an image signal, and driving of each light source. It is explanatory drawing which shows the display state of each image division area in each state of FIG. It is a perspective view which shows a mobile telephone provided with a liquid crystal device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal device, 2 Liquid crystal panel, 3 Backlight unit (illuminating means) 4 Control means, 15 Image display area, 15A, 15B Image division area, 21 Light guide plate, 21A, 21B Light guide division area, 22, 23 Light source, 25 reflective film (light-shielding film), 26A to 26C, 27A to 27C LED element (light emitting member), 100 mobile phone (electronic device), V vertical scanning direction (one direction)

Claims (5)

An electro-optical panel that displays an image in an image display area in accordance with a supplied image signal;
Illumination means capable of illuminating a plurality of colors of illumination light toward the electro-optical panel;
Control means for controlling the supply of the image signal to the electro-optical panel and the driving of the light source, respectively.
The image display area is divided into a plurality of image division areas;
The light means is divided into a plurality of light guide division regions corresponding to the plurality of image division regions, and a light guide plate provided with a light shielding film at the boundary between two adjacent light guide division regions; and A plurality of light sources that emit the illumination light toward each of a plurality of light guide divided regions;
The control means sequentially supplies the image signal to each of the plurality of image division areas, and the light source provided in the light guide division area corresponding to the image division area to which the image signal is being supplied is not driven. And the other light source is driven.   The electro-optical device according to claim 1, wherein the light shielding film is a reflective film that reflects the illumination light. The control means sequentially supplies the image signal for each column along one direction of the image display area,
The electro-optical device according to claim 1, wherein the plurality of image division regions are arranged along the one direction.   4. The electro-optical device according to claim 1, wherein each of the plurality of light sources includes a plurality of light-emitting members that emit light of the plurality of colors. 5.   An electronic apparatus comprising the electro-optical device according to claim 1.

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