JP2010182062A - Electrooptical device and electronic apparatus - Google Patents

Abstract

To detect a touch position on a touch panel more appropriately.
An electro-optical device used in combination with a touch panel function for detecting contact with light, wherein display control means for displaying an image on a display screen based on input image data, and irradiation from the display screen When the touch panel function detects a contact position on the display screen by reflected light of the light that is applied, the partial image of the display screen is higher than the image of the partial region indicated by the input image data And high brightness area display means for displaying a high brightness area having brightness.
[Selection] Figure 6

Description

  The present invention relates to an electro-optical device that performs screen display for a touch panel and an electronic apparatus including the same.

Conventionally, a touch panel for inputting information by touching a screen has been used. The touch panel is arranged so as to overlap with an electro-optical device such as a liquid crystal device. When the user touches the display screen, the touch position is detected by the touch panel, and data corresponding to the display content can be input.
In such a touch panel, one that detects a contact position with an optical sensor is known. A touch panel that detects the contact position with an optical sensor detects the user's contact position by detecting the light reflected from the fingertip part in response to the shadow of the finger due to external light or the backlight of the electro-optical device. can do.
In addition, as a technique regarding the touch panel, for example, a technique described in Patent Document 1 can be cited.

JP 2006-301864 A

However, in the touch panel that detects the contact position by the optical sensor, the intensity of external light is not sufficient, and the brightness of the image displayed on the electro-optical device is low and the light emitted from the electro-optical device is weak. It may be difficult to detect the shadow of a finger due to external light or to detect reflected light from the fingertip, and the touch position on the touch panel may not be detected properly.
In the technique described in Patent Document 1, the invisible light emitting cell and the light receiving sensor are provided in the liquid crystal panel. According to this technique, it is necessary to provide the invisible light emitting cell and the light receiving sensor. Therefore, it is difficult to adopt from the viewpoint of cost.
As described above, it is difficult for the conventional technology to appropriately detect the contact position with respect to the touch panel.
The subject of this invention is performing the detection of the contact position with respect to a touchscreen more appropriately.

In order to solve the above problems, an electro-optical device according to one embodiment of the present invention includes:
An electro-optical device that is used in combination with a touch panel function that detects contact by light, and that displays an image on a display screen based on input image data (for example, the panel control unit 13 in FIG. 1) And when the touch panel function detects a contact position on the display screen by reflected light of light emitted from the display screen, the input image data indicated by the input image data is displayed in a partial area of the display screen. And a high brightness area display means for displaying a high brightness area having a higher brightness than the image of the area (for example, a panel control section 13 for executing the procedure shown in the flowchart of FIG. 5).
With such a configuration, when the touch panel function detects contact by the reflected light of light emitted from the display screen, if the intensity of light emitted from the display screen is not sufficient, A high brightness area is displayed.

Therefore, it is possible to irradiate a finger or the like that contacts the display screen with stronger light, and it is possible to more appropriately detect the contact position with respect to the touch panel.
An electro-optical device according to one embodiment of the present invention includes:
As a method for detecting contact by the touch panel function, mode selection means for selecting either a first mode using external light or a second mode using light emitted from the display screen (for example, FIG. 1). A processing method selection module 23), and determination means (for example, the processing method selection module 23 in FIG. 1) for determining whether the intensity of light emitted from the display screen is equal to or less than a set threshold value; The high brightness area display means is a case where the second mode is selected by the mode selection means, and the intensity of light irradiated from the display screen by the determination means is When it is determined that the threshold value is equal to or less than a set threshold value, the high luminance region is displayed.

With such a configuration, the touch panel that switches between the first mode for detecting contact by external light and the second mode for detecting contact using light emitted from the display screen performs irradiation from the display screen. By determining the intensity of the light to be applied, the touch position with respect to the touch panel can be detected more appropriately even when the brightness of outside light is insufficient and the image displayed on the display screen is dark.
An electro-optical device according to one embodiment of the present invention includes:
The high luminance area display means displays a white area in a partial area of the display screen.
With such a configuration, it is possible to more effectively irradiate a finger or the like that contacts the touch panel.

An electro-optical device according to one embodiment of the present invention includes:
The high-intensity area display means displays the high-intensity area while moving the display area to any one area that divides the display screen.
With such a configuration, it is possible to irradiate a wide area on the display screen, and thus it is possible to more appropriately detect the touch position on the touch panel.
In addition, an electro-optical device according to one embodiment of the present invention includes:
The high-intensity area display means displays the high-intensity area while moving the display area to a plurality of areas among the areas into which the display screen is divided.
With such a configuration, it is possible to irradiate a finger or the like in a plurality of regions on the display screen, and thus it is possible to more appropriately detect a contact position with respect to the touch panel.

An electro-optical device according to one embodiment of the present invention includes:
The high-intensity area display means displays the high-intensity area in a plurality of areas sandwiching a reference position set on the display screen among areas obtained by dividing the display screen.
With such a configuration, the light is irradiated from both sides through the white region with respect to the reference position, so that the fingertip position can be detected more appropriately.
An electro-optical device according to one embodiment of the present invention includes:
The high-intensity area display means displays the high-intensity area in an area selected at random from among the areas obtained by dividing the display screen.
With such a configuration, it is possible to irradiate the entire area on the display screen evenly, and to detect the fingertip position more appropriately.

An electronic device according to one embodiment of the present invention includes:
A touch panel unit that detects contact with light, a display control unit that displays an image on the display screen based on input image data, and an intensity of light emitted from the display screen is equal to or less than a set threshold value And the light emitted from the display screen when it is determined by the determining means that the intensity of the light emitted from the display screen is not more than a set threshold value. When the touch panel unit detects a contact position on the display screen by the reflected light, a high brightness having higher brightness than the image of the partial area indicated by the input image data in the partial area of the display screen. It has a high brightness area display means for displaying a brightness area.

With such a configuration, when the touch panel function detects contact by the reflected light of light emitted from the display screen, if the intensity of light emitted from the display screen is not sufficient, A white area is displayed.
Therefore, it is possible to irradiate a finger or the like that contacts the display screen with stronger light, and it is possible to more appropriately detect the contact position with respect to the touch panel.
Thus, according to the present invention, it is possible to more appropriately detect the contact position with respect to the touch panel.

It is a figure which shows the structure of the liquid crystal display device 10 incorporating a touchscreen system. It is a figure which shows a mode when the fingertip 8 of the front-end | tip of the finger | tip 6 touches the surface of the glass substrate 11. FIG. It is the figure which showed typically the brightness seen from the back side of the glass substrate 11, when the fingertip 8 of the front-end | tip of the finger 6 touched the surface of the glass substrate 11. FIG. 4 is a flowchart illustrating a procedure for detecting a fingertip position performed by a touch panel control unit 21. It is a flowchart which shows the procedure of the white area | region display method performed in order that the panel control part 13 may assist fingertip position detection. It is the figure which showed typically the white region display method which the panel control part 13 performs. It is a figure which shows the portable information terminal incorporating the liquid crystal display device by this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
(Constitution)
FIG. 1 is a diagram showing a configuration of a liquid crystal display device 10 incorporating a touch panel system.
A liquid crystal display device 10 as an electro-optical device includes a glass substrate 11 on which a pixel device 16 and the like are disposed, and a circuit and the like provided outside the glass substrate 11. The liquid crystal display device 10 is arranged in a matrix on the glass substrate 11, an input unit 12 for inputting conditions for the operation of the liquid crystal display device 10, a panel control unit 13 for controlling the operation of the liquid crystal display panel. A gate driving unit 14 and a data driving unit 15 for selecting a plurality of pixel devices 16 and supplying data, a backlight 17 provided behind the glass substrate 11, and a backlight driving unit 18 are included.

The liquid crystal display device 10 includes the following as elements unique to the touch panel system. That is, a plurality of finger detection optical sensors 30 arranged in a matrix like the pixel device 16 on the glass substrate 11, and an optical sensor sensing unit 19 that detects the outputs of the plurality of finger detection optical sensors 30. In addition, an external light sensor 20 installed when detecting external light and a touch panel control unit 21 for detecting contact of a fingertip with the glass substrate of the liquid crystal panel are included.
In addition to these elements, the touch panel system includes an input unit 12 that implements a function of inputting the brightness of external light, a panel control unit 13 that implements a function of controlling the entire touch panel system, a backlight 17, and a backlight. The drive part 18 grade | etc., Is also included.
The elements constituting the liquid crystal display device 10 are connected to each other by internal wiring or internal connection.

The glass substrate 11 is a so-called liquid crystal panel in which one glass substrate on which transparent electrodes, switching transistors, and the like are arranged in a matrix is opposed to the other glass substrate and liquid crystal is sealed between them. Point to. In the central part of the glass substrate 11, pixel devices 16 for liquid crystal display are arranged in a matrix, and in the peripheral part, the gate driving unit 14 and the data driving unit 15 are arranged.
The pixel device 16 includes a switching transistor selected by a gate line and a data line, upper and lower transparent electrodes, a liquid crystal that is a display element held between the upper and lower transparent electrodes, a holding capacitor, and the like.

  The gate driving unit 14 and the data driving unit 15 are circuit units including a selection circuit for selecting a plurality of gate lines and data lines. The switching transistors of the pixel device 16, the transistors constituting the gate driving unit 14 and the data driving unit 15 are formed on a glass substrate by a low-temperature polysilicon transistor formation technology, a high-temperature polysilicon transistor formation technology, an amorphous transistor formation technology, or the like. be able to.

  The finger detection optical sensor 30 disposed on the glass substrate 11 on the matrix uses external light or backlight light to detect the shape of the fingertip (or pen-like instrument) that touches the glass substrate 11. An electronic device having Specifically, a transistor with high sensitivity to light can be used as the finger detection optical sensor 30. For example, a MOS transistor (Metal Oxide Semiconductor Transistor) used as a switching element of the pixel device 16 can be used. In general, the leakage current of a MOS transistor is highly sensitive to light and can be used. The gate terminal of the MOS transistor may be held at a constant potential and the MOS transistor may be turned off to use the light dependency of the leakage current, or the gate terminal may be opened to further increase the sensitivity to light. In FIG. 1, an n-channel transistor with an open gate terminal is used as a finger detection photosensor 30 with high sensitivity to light, its drain terminal is connected to a common power source, and its source terminal is connected to the photosensor sensing unit 19. The configuration to be shown is shown.

  The optical sensor sensing unit 19 is a sensing circuit that detects the magnitude of leakage current of each of the plurality of finger detection optical sensors 30 arranged in a matrix. Leakage current sensing can be performed for each finger detection optical sensor 30, and a plurality of finger detection optical sensors 30 can also be detected collectively in block units obtained by dividing the matrix into a certain range. In the latter case, since the value of the leakage current increases, it becomes easy to distinguish between a portion that is strongly irradiated with light and a portion that is weakly irradiated. FIG. 1 shows an example in which one finger detection optical sensor 30 is arranged for each pixel device 16 and nine finger detection optical sensors 30 are collectively sensed, and is schematically illustrated as a 3 × 3 pixel. One finger detection optical sensor 30 is shown as a representative in the center of the device block. The output of the optical sensor sensing unit 19 is acquired by the touch panel control unit 21.

The backlight 17 is a lamp for illuminating the display unit of the glass substrate 11 from the back. Here, the back means the back with respect to the display surface of the liquid crystal display device 10. If FIG. 1 is a view of the liquid crystal display device 10 as viewed from the display surface side, a backlight 17 is disposed on the back side of the paper surface, and light is irradiated from the back side of the paper surface toward the front side of the paper surface. The backlight drive unit 18 is a circuit having functions for turning on and off the backlight 17 and adjusting brightness.
The input unit 12 is operated by a user or the like, and has a function of giving instructions to the panel control unit 13 about turning on and off the liquid crystal panel and selecting a display mode. Specifically, the input unit 12 includes an external switch, an external keyboard, and the like. can do.

  The input unit 13 has a function of inputting information related to the brightness of external light. Information about the brightness of outside light includes a very bright environment like outdoor in the middle of summer, an average office brightness environment, a rainy and dark environment, and a midnight and dark environment. It is information such as being. As will be described later, in the touch panel system, the information on the brightness of the external light has a problem in comparison with the brightness of the backlight light. Therefore, as described above, the brightness of the external light may be input by the user with a changeover switch or the like for several brightness ranks, and is input in a coarser classification in relation to the brightness of the backlight light. It is good to do. Information regarding the brightness of the input external light is acquired by the touch panel control unit 21.

The panel control unit 13 has a function of controlling each element of the liquid crystal display device 10 as a whole and a function of specifying the position of a fingertip or the like that has touched the glass substrate 11 as described above. Specifically, it can be constituted by a microprocessor or the like. The panel control unit 13 receives a backlight mode notification signal from a processing method selection module 23 described later, and further sets an image to be displayed (an image indicated by image data input to the panel control unit 13). If it is darker than the threshold value, the white area is displayed in order to irradiate the fingertip or the like according to the white area display method described later.
In addition, when displaying a white region for irradiating a fingertip or the like, the panel control unit 13 automatically displays the white region, and the user manually switches the changeover switch of the input unit 12 to display the white region. It can also be displayed.

The outside light sensor 20 is a sensor that detects the brightness of the outside light. Instead of inputting the brightness of the outside light from the input unit 12, the outside light sensor 20 detects the brightness of the outside light and uses the touch panel control unit 21. Output to.
The touch panel control unit 21 has a function of specifying the position of a fingertip or the like that has touched the glass substrate 11 regardless of the brightness of external light. Specifically, the touch panel control unit 21 can be configured by a microprocessor or the like, and includes an external light brightness acquisition module 22 that acquires information on the brightness of external light from the input unit 12 or the external light sensor 20, and the brightness of external light. Acquire data of a processing method selection module 23 for selecting an image processing method (external light mode or backlight mode described later) suitable for fingertip detection according to the brightness of the backlight light, and the optical sensor sensing unit 19 And a fingertip position specifying module 25 for specifying the fingertip position. Such a function can be realized by software, specifically, by executing a program corresponding to each function. Some of these functions may be realized by hardware.

(Operation)
The operation of the liquid crystal display device 10 having the above configuration, particularly the operation of the touch panel system, will be described in detail below in association with each function of the touch panel control unit 21.
First, when external light and backlight light exist, how the finger detection optical sensor 30 works when a finger touches the glass substrate 11 will be described, and a fingertip position detection procedure will be described based on this. Will be described using a flowchart and the like.
FIG. 2 is a diagram illustrating a state when the fingertip 8 at the tip of the finger 6 touches the surface of the glass substrate 11. The glass substrate 11 includes a pixel device 16 therein, but the illustration thereof is omitted here.

  The backlight 17 irradiates backlight light 26 from the back surface of the glass substrate 11 and illuminates the belly portion of the finger 6 from the glass substrate 11 side. On the other hand, the external light 4 is poured from the upper side of the finger 6 to make a shadow of the finger 6 on the glass substrate 11. The finger detection optical sensors 30 arranged in a matrix are arranged between the surface of the glass substrate 11 and the backlight 17, and the bottom side and the side are shielded so as not to directly receive the light from the backlight 17. Has been. Therefore, the finger detection optical sensor 30 detects only light from the surface side of the glass substrate 11.

  The light from the surface side of the glass substrate 11 includes a component due to the external light 4 and a component in which the backlight light 26 is reflected back to the finger 6. As for the component due to the external light 4, as shown in FIG. 2, the part (A) that is shaded by the finger 6 by the external light 4, the part (B) where the fingertip 8 is in contact with the glass substrate 11, and the finger 6 The brightness detected by the finger detection optical sensor 30 differs from the portion (C) where the external light 4 is incident on the glass substrate 11 as it is. Further, the component of the backlight light 26 is also reflected from the part (A) reflected from the finger 6 by the backlight light 26 and the fingertip 8 in contact with the glass substrate 11 as shown in FIG. The brightness detected by the finger detection optical sensor 30 is different between the coming part (B) and the part (C) where the backlight light 26 is irradiated to the outside of the glass substrate 11 without being blocked by the finger 6. come.

FIG. 3 is a diagram schematically showing the brightness viewed from the back side of the glass substrate 11 when the fingertip 8 at the tip of the finger 6 touches the surface of the glass substrate 11.
The diagram shown in FIG. 3 corresponds to the result of two-dimensional brightness detection of a plurality of finger detection photosensors 30 arranged in a matrix. Here, in FIG. 3, in order to show the brightness, the bright side is white, and the density of the oblique lines is increased as it becomes darker.

  FIG. 3A is a diagram showing a case where the external light 4 is overwhelmingly brighter than the backlight light 26, and the part of the finger 6 is detected as a shadow part 70. This shadow portion 70 corresponds to (A) of FIG. The part of the fingertip 8 is included in the shadow part 70, but is in close contact with the glass substrate 11, so that the backlight light 26 is compared to other finger parts not in close contact with the glass substrate 11. Reflected more strongly. Therefore, the part of the fingertip 8 is detected as a bright oval part 80 in a dark shadow. This bright oval portion 80 corresponds to (B) of FIG. The background portion 60 that is not a shadow of the finger is brightest because the external light 4 reaches the finger detection optical sensor 30. This bright background portion 60 corresponds to (C) of FIG.

  FIG. 3B shows a case where the external light 4 is dark and the backlight light 26 is dominant, and the reflection from the part of the finger 6 is detected as a finger-shaped part 72. This finger-shaped portion 72 corresponds to (A) of FIG. The part of the fingertip 8 is included in the finger-shaped part 72, but is in close contact with the glass substrate 11, so that the backlight light 26 is compared with other finger parts that are not in close contact with the glass substrate 11. Reflected more strongly. Accordingly, the finger-shaped portion 72 is detected as a relatively bright elliptical portion 82. This relatively bright oval portion 82 corresponds to FIG. The background portion 62 that does not become the shadow of the finger is the darkest because the backlight 26 is not reflected on the finger 6 and is irradiated to the outside, so that there is almost no light reaching the finger detection optical sensor 30. This dark background portion 62 corresponds to (C) of FIG.

  Thus, when the external light 4 is dominant, the background portion 60 is the brightest, the oval portion 80 corresponding to the fingertip 8 is next bright, and the shadow portion 70 of the finger 6 is the darkest. On the other hand, when the backlight 25 is dominant, the background portion 62 is the darkest, then the finger-shaped portion 72 corresponding to the finger 6 is dark, and finally the elliptical portion 82 corresponding to the fingertip 8 is the brightest. As described above, due to the relative brightness difference between the external light 4 and the backlight light 26, the relationship between the brightness of the portion corresponding to the fingertip 8 and the brightness of the other portions, together with the brightness itself, the brightness. It can be seen that the order of changes relatively. Based on this, the touch panel control unit 21 selects an image processing method for fingertip detection according to the brightness of external light.

Hereinafter, a procedure for detecting the fingertip position will be described with reference to a flowchart and the like.
As described with reference to FIG. 3, when the fingertip comes into contact with the glass substrate 11, the brightness or darkness is 3 in the three portions including the background portion, the portion corresponding to the finger 6, and the portion corresponding to the fingertip 8. The fingertip position can be detected by noting that there is a stage.
FIG. 4 is a flowchart showing a procedure of fingertip position detection performed by the touch panel control unit 21. The flowchart shown in FIG. 4 is started when the liquid crystal display device 10 is turned on.

In FIG. 4, when performing fingertip position detection, the touch panel control unit 21 first acquires ambient light brightness (step S <b> 11). This is realized by the function of the outside light brightness acquisition module 22. Specifically, the information on the brightness of the external light input by the user is acquired from the input unit 12, or the output of the external light sensor 20 is acquired instead of acquiring the input of the user.
And the touch panel control part 21 judges whether the brightness of the acquired external light is more than a threshold value (step S12). The size of the threshold value is used to distinguish between the case where the external light 4 is dominant and the case where the backlight light 26 is dominant, as described with reference to FIG. Can be determined in advance.

The touch panel control unit 21 selects the processing procedure of Steps S13-S14-S15-S16 when the brightness of the acquired external light is equal to or greater than the threshold value, and when the brightness of the acquired external light is less than the threshold value, Select a processing procedure. Therefore, the process of step S12 is also a selection process including selecting one from different processing procedures. Step S12 is executed by the function of the processing method selection module 23.
The processing procedure of steps S13-S14-S15-S16 is a processing procedure when the external light 4 is dominant (hereinafter referred to as “external light mode”). Here, the function of the optical sensor data acquisition module 24 acquires detection data such as the leakage current of each finger detection optical sensor 30 arranged in a matrix from the optical sensor sensing unit 19, converts this to brightness, Further, it is converted into data such as a two-dimensional brightness map in association with the position on the plane of the glass substrate 11. Based on the two-dimensional brightness map data, the following processing is performed.

If it is determined in step S12 that the brightness of the acquired external light is greater than or equal to the threshold value, the touch panel control unit 21 notifies the panel control unit 13 that the external light mode has been selected (hereinafter, referred to as “light control mode”). (Referred to as “external light mode notification signal”) (step S13).
Next, the touch panel control unit 21 detects a shadow of a finger due to external light (step S14). 3A, the lightest background portion 60 and the darkest shadow portion 70 are distinguished.
Furthermore, the touch panel control unit 21 detects a fingertip portion in the shadow of the finger (step S15). 3A, the darkest shadow portion 70 and the relatively bright elliptical portion 80 are distinguished. In this manner, in steps S14 to S15, two parts having different darkness are distinguished from each other surrounded by the bright background part. That is, the elliptical portion 80 is detected by distinguishing three levels of brightness.

Then, the position of the fingertip portion detected in step S15 is specified as the fingertip position (step S16). The fingertip position is specified by the function of the fingertip position specifying module 25.
The processing procedure of steps S17-S18-S19-S20 is a processing procedure when the backlight 26 is dominant (hereinafter referred to as “backlight mode”).
In step S12, when it is determined that the brightness of the acquired external light is less than the threshold value, the touch panel control unit 21 notifies the panel control unit 13 that the backlight mode has been selected (hereinafter, referred to as “light source mode”). (Referred to as “backlight mode notification signal”) (step S17).

Next, the touch panel control unit 21 detects reflection from the finger by backlight light (step S18). If it demonstrates according to FIG.3 (b), the darkest background part 62 and the next dark finger-shaped part 72 will be distinguished.
Further, the touch panel control unit 21 detects the fingertip portion in the reflection from the finger (step S19). 3B, the second darkest finger-shaped portion 72 and the brightest elliptical portion 82 are distinguished. As described above, in steps S18 to S19, two parts having different brightness are distinguished from each other in the part surrounded by the dark background. That is, the ellipse portion 82 is detected by distinguishing three levels of brightness.
Then, the position of the fingertip portion detected in step S19 is specified as the fingertip position (step S20). The fingertip position is specified by the function of the fingertip position specifying module 25.

Next, a white area display method for assisting fingertip position detection will be described.
FIG. 5 is a flowchart showing a procedure of a white area display method executed by the panel control unit 13 to assist the fingertip position detection. This procedure is realized by the function of the panel control unit 13.
The flowchart shown in FIG. 5 is started when the liquid crystal display device 10 is turned on.
In FIG. 5, when performing white area display, the panel control unit 13 determines whether or not the touch panel control unit 21 is performing fingertip position detection in the backlight mode (step S <b> 30).
At this time, the panel control unit 13 detects whether the backlight mode notification signal is input from the touch panel control unit 21 or whether the external light mode notification signal is input, thereby determining whether the backlight mode is set. Can be determined.

  In step S30, when the touch panel control unit 21 determines that the fingertip position is detected in the backlight mode, the panel control unit 13 determines whether the brightness of the image displayed on the screen of the liquid crystal display device 10 is equal to or less than the threshold value. Is determined (step S31). At this time, the brightness of the image can be defined as, for example, a value obtained by adding the luminances of all the pixels of the image data input to the panel control unit 13. Then, the fingertip position detection is appropriately performed by performing various experiments such as detecting the reflection of the backlight 26 by the finger by variously changing the luminance addition value in all the pixels of the image data input to the panel control unit 13. Can be determined as a threshold value used in the determination in step S31.

If it is determined in step S31 that the brightness of the image displayed on the screen of the liquid crystal display device 10 is equal to or less than the threshold value, the panel control unit 13 performs white area display processing to irradiate the fingertip (step S32). The process proceeds to step S30.
On the other hand, if it is determined in step S31 that the brightness of the image displayed on the screen of the liquid crystal display device 10 exceeds the threshold value, the panel control unit 13 displays the image indicated by the image data input to the panel control unit 13. The information is displayed as it is (step S33), and the process proceeds to step S30.

Here, when displaying the white area in step S32 of FIG. 5, for example, a plurality of blocks are set on the display screen, and the white area is moved one block at a time in synchronization with the refresh rate in the liquid crystal display device 10. Can be displayed.
Specifically, when the refresh rate of the liquid crystal display device 10 is 60 Hz, the area on the display screen is divided into 60 blocks in a matrix, and the block that displays the white area every 1/60 seconds is changed from the upper left block. It is possible to move to the lower right block so as to scan the entire screen (for example, raster scan).

FIG. 6 is a diagram schematically illustrating a white area display method executed by the panel control unit 13.
In FIG. 6, the area of the display screen is divided into 60 blocks, and the panel control unit 13 starts scanning the white area from the upper leftmost block. Then, the panel control unit 13 moves the white area to the right adjacent block every 1/60 seconds, and when the white area reaches the right end block, scans the block from the left end to the right end of the next stage. Repeat these steps.
As a result, as shown in the example of the 26th frame in FIG. 6, it is possible to detect contact with the touch panel by the white area being scanned irradiating the user's finger.

Note that the timing for moving the block that displays the white area may be set independently of the refresh rate of the liquid crystal display device 10. That is, for the movement of the block displaying the white area, it is possible to obtain a timing suitable for detection of the fingertip position by experiment and set it to the movement timing.
As described above, in the liquid crystal display device 10 according to the present embodiment, when the touch sensor control unit 21 outputs the backlight mode notification signal to the panel control unit 13, the panel control unit 13 displays the brightness of the image to be displayed. Is determined to be less than or equal to the threshold value. When it is determined that the brightness of the image to be displayed is equal to or less than the threshold value, the panel control unit 13 sequentially displays the white areas while scanning the display screen.

Therefore, when the image input to the panel control unit 13 is dark and is displayed as it is, even when sufficient light is not emitted from the display screen to the fingertip, the fingertip is more strongly irradiated by displaying the white area. can do.
Therefore, even when the brightness of the external light is insufficient and the image displayed on the screen of the liquid crystal display device 10 is dark, the fingertip position in contact with the touch panel can be detected more appropriately.

In the above embodiment, the touch panel function is described as being combined with a liquid crystal display device in which pixels are arranged in a matrix, but may be combined with a liquid crystal display device having a pixel arrangement that is not in a matrix. For example, it may be combined with a display panel in which segmented pixels are arranged. In addition, the liquid crystal display device has been described on the assumption that the gate driving unit and the data driving unit circuit are configured on a transparent substrate such as a glass substrate in addition to the pixels arranged in a matrix and the fingertip detection light sensor. Devices other than this may be arranged on the glass substrate, and conversely, only the pixels and the fingertip detection light sensor may be arranged on the glass substrate.
In the above embodiment, the present invention has been described as being applied to a liquid crystal display device. However, a plasma display, an LED (Light Emitting Diode) display, an organic EL (Electro Luminescence) display, etc. The present invention can be applied to an electro-optical device that can emit light from a display screen.

(Application 1)
In the first embodiment, the white area for irradiating the fingertip or the like has been described as being scanned and displayed in order from the upper left to the lower right of the display screen. However, the white area is selected by randomly selecting a block in the display screen. Can be displayed.
As a result, the entire area on the display screen can be evenly irradiated, and the fingertip position can be detected more appropriately.

(Application example 2)
In the first embodiment, one white area is displayed per frame. However, a plurality of white areas may be displayed in one frame. Specifically, it is possible to divide the display screen into a plurality of sections, display one white area per frame for each section, and sequentially scan the white areas in each section. As a result, the frequency at which the fingertip approaches the white region is increased, and the fingertip position can be detected more appropriately.

At this time, the plurality of sections displaying the white region can be selected so that the reference position (for example, the intersection of diagonal lines or the center of the bottom) is sandwiched between the display screens.
In this case, since the light is irradiated from both sides via the white region with respect to the reference position, the fingertip position can be detected more appropriately.
Note that by setting a position in the display screen where the frequency of contact with the user is high as the reference position, it is possible to irradiate the fingertip or the like more effectively.

(Application 3)
In the above description, the white area is displayed in order to effectively irradiate the fingertip or the like. However, in order to irradiate the fingertip or the like, an area other than white can be displayed.
That is, in order to irradiate a fingertip or the like, it is only necessary to display a region where the light emitted from the display screen is stronger than when the input image is displayed as it is.
Therefore, for example, it is possible to display a part of the region in the input image as a high luminance region with higher luminance.
In such a case, it is possible to irradiate a finger or the like while making a smaller change to the input image, so that the high luminance region can be made inconspicuous on the display screen.

(Application 4)
An electro-optical device such as a liquid crystal display device to which the present invention is applied can be applied to various electronic devices having a touch panel function.
FIG. 7 is a schematic diagram illustrating an example in which the electro-optical device of the present invention is applied to the portable information terminal 100 as an electronic apparatus.
As an electronic apparatus to which the electro-optical device is applied, in addition to a portable information terminal as shown in FIG. 7, for example, a personal computer, a digital still camera, a liquid crystal television, a viewfinder type video tape recorder, a car navigation device, a pager, an electronic notebook Calculators, word processors, workstations, videophones, POS terminals and the like. The electro-optical device such as the above-described liquid crystal display device can be applied as a display unit having a touch panel function provided in these various electronic devices.

4 external light, 6 fingers, 8 fingertips, 10 liquid crystal display device, 11 glass substrate, 12 input unit, 13 panel control unit, 14 gate drive unit, 15 data drive unit, 16 pixel device, 17 backlight, 18 backlight drive Unit, 19 optical sensor sensing unit, 20 external light sensor, 21 touch panel control unit, 22 external light brightness acquisition module, 23 processing method selection module, 24 optical sensor data acquisition module, 25 fingertip position specifying module, 26 backlight light, 30 optical sensors for finger detection, 60, 62 background part, 70 shadow part, 72 finger part, 80, 82 oval part, 100 portable information terminal

Claims (8)

An electro-optical device used in combination with a touch panel function for detecting contact by light,
Display control means for displaying an image on the display screen based on the input image data;
When the touch panel function detects a contact position on the display screen by reflected light of light emitted from the display screen, the input image data indicated by the input image data is displayed in a partial area of the display screen. A high brightness area display means for displaying a high brightness area having a higher brightness than the image of the area;
An electro-optical device comprising: Mode selection means for selecting one of a first mode using external light and a second mode using light emitted from the display screen as a method for detecting touch by the touch panel function;
Determination means for determining whether the intensity of light emitted from the display screen is equal to or less than a set threshold;
Have
The high brightness area display means is a threshold in which the second mode is selected by the mode selection means, and the intensity of light emitted from the display screen is set by the determination means. The electro-optical device according to claim 1, wherein the high-luminance region is displayed when it is determined that the following is true.   The electro-optical device according to claim 1, wherein the high-luminance area display unit displays a white area in a partial area of the display screen.   4. The high-brightness area display means displays the high-brightness area while moving the display area to any one of the divided display screens. The electro-optical device according to 1.   The high-brightness area display means displays the high-brightness area while moving a display area to a plurality of areas among the areas obtained by dividing the display screen. The electro-optical device according to Item.   6. The high-brightness area display means displays the high-brightness area in a plurality of areas sandwiching a reference position set on the display screen among areas obtained by dividing the display screen. Electro-optic device.   4. The electricity according to claim 1, wherein the high-intensity area display unit displays the high-intensity area in a randomly selected area among areas into which the display screen is divided. 5. Optical device. A touch panel unit for detecting contact by light;
Display control means for displaying an image on the display screen based on the input image data;
When the touch panel unit detects a contact position on the display screen by reflected light of light emitted from the display screen, the partial area indicated by the input image data in the partial area of the display screen High brightness area display means for displaying a high brightness area having a higher brightness than the image of
An electronic device comprising:

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