JP2009223102A - Display panel and electronic apparatus including the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To broaden a light receiving area and to avoid an increase in the number of manufacturing processes, in a display panel in which a light receiving element is formed. <P>SOLUTION: A plurality of sub-pixels for controlling brightness are included. The sub-pixel includes a TFT (thin film transistor) substrate in which a first TFT for changing brightness according to applied voltage, a second TFT for receiving external light, a charge storing section for storing a charge based on the light receiving amount of the second TFT, and a third TFT to output a voltage based on the charge amount stored in the charge storing section. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

The present invention relates to a display panel including a TFT for detecting a line of sight in a sub-pixel and an electronic apparatus having the display panel.

Conventionally, detection of the line-of-sight direction has been used in various devices. As a method for detecting the gaze direction, there is a technique for detecting the gaze direction from the positional relationship between the cornea and the sclera by measuring the intensity of the reflected light caused by the difference in reflectance between the cornea (black eye) and the sclera (white eye). (See Patent Document 1). Also,
Assuming that the line-of-sight direction is a vector connecting the pupil and the center of curvature of the cornea, the center of the pupil and the Purkinje image (
There is a technique for detecting the line-of-sight direction from the position of the reflected image on the corneal surface (see Patent Document 2).
.

One of gaze detection uses is a head-mounted image device. In this apparatus, infrared rays from a diode are irradiated on the eye, reflected light of the eye is picked up by a CCD camera, the picked-up image is analyzed to determine the gaze direction, and the position of the gaze is superimposed on the video. Further, it has been considered that the head-mounted type is a glasses type, and the line-of-sight direction is output to a personal computer and used for input such as movement of the cursor, click, double-click (see Patent Document 3).

However, the eyeglass-type line-of-sight detection device has a problem that the detection accuracy of the line-of-sight direction is poor.
This is because the eyeglass-type gaze detection device is not attached to the head because the CCD camera that captures the eyes is not integrated with the display unit of the personal computer that is the gaze target.
Therefore, as shown in Patent Document 4, it has been considered to arrange a photoelectric conversion element in the liquid crystal panel. FIG. 12 is FIG. 1 of Patent Document 4, and is an equivalent circuit diagram of the liquid crystal panel in the automatic focus of the camera. A TFT 902 (thin film transistor) that changes the alignment of the liquid crystal is connected to the data line 903.
The gate lines 909 are arranged in a matrix. A photoelectric conversion element 915 is disposed on the extension of the matrix. If the photoelectric conversion element is thus arranged in the liquid crystal panel, the means for detecting the reflected light of the eye and the object of the line of sight are integrated, thereby improving the accuracy of detection of the line of sight direction.
Japanese Patent No. 3038375 JP 2003-79777 A JP 2000-187552 A JP 2000-305715 A

However, the photoelectric conversion element of Patent Document 4 is outside the display pixel region (outside the display matrix).
Therefore, a great restriction is imposed on the design of the positional relationship between the infrared irradiation means and the eye and the photoelectric conversion element. There is also a problem that the size of the liquid crystal panel becomes large. For example,
When the cursor movement of Patent Document 3 is applied to a folding notebook personal computer,
Since the light receiving position of the reflected light of the eye changes up and down depending on the user and the opening angle of the hinge, it is difficult to receive the reflected light outside the display pixels. Further, when the reflected light is received outside the display pixel region, the size of the notebook personal computer increases.

Moreover, since the photoelectric conversion element of Patent Document 4 is composed of photodiodes other than TFTs, there is also a problem that man-hours increase.

The present invention has been made in view of the above-described problems. By forming a photoelectric conversion element made of TFT in a display pixel region, the light receiving range of the display panel is widened, and the number of manufacturing steps is increased. To avoid. In addition, when the present invention is applied to a foldable notebook personal computer, adjustment of line-of-sight detection accompanying the inclination of the hinge is easily performed.

In order to solve the above problems, the display panel of the present invention has a plurality of sub-pixels for which luminance control is performed,
The sub-pixel includes a first TFT that changes luminance according to an applied voltage, a second TFT that receives external light, a charge accumulation unit that accumulates charge according to the amount of light received by the second TFT, and the charge A TFT substrate is provided on which a third TFT that outputs a voltage corresponding to the amount of charge accumulated in the accumulation unit is formed.

In this manner, by forming the TFT photodetecting element in the subpixel TFT substrate, light can be received in a wide area of the display panel. In addition, an increase in the number of manufacturing steps can be avoided.

The source terminal of the first TFT and the source terminal of the second TFT are connected to the same source driver, and the gate terminal of the first TFT and the gate terminal of the third TFT are connected to the same gate driver.

  Thereby, it is easy to display the light receiving position of the eye with the same subpixel as the light receiving.

In order to solve the above problems, an electronic device having a display panel of the present invention is an electronic device having a display panel having a plurality of sub-pixels for which brightness control is performed,
The sub-pixel includes a first TFT that changes luminance according to an applied voltage, a second TFT that receives external light, a charge storage unit that stores charges according to the amount of light received by the second TFT, and the charge storage A TFT substrate formed with a third TFT that outputs a voltage corresponding to the amount of charge accumulated in the part,
Light emitting means for irradiating light toward the user's eyes, line of sight detecting means for calculating the line of sight based on the output voltage of the third TFT, and the position of the reflected light of the eye received by the display panel on the display panel Control means for displaying is provided.

Thereby, the above-mentioned display panel can be applied to gaze detection. Further, since the light receiving position of the reflected light of the eye is displayed on the display panel, the gaze detection can be easily adjusted.

The control means outputs an applied voltage based on the output voltage of the third TFT to the first TFT in the same sub-pixel.

Thereby, the light receiving position of the reflected light of the eye can be displayed on the display panel easily and accurately.

In addition, adjustment means for changing the irradiation position of the light emitting means is provided. Thereby, the light receiving position of the reflected light of the eye can be easily adjusted.

Hereinafter, the best embodiment of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a display panel and an electronic apparatus having the display panel for embodying the technical idea of the present invention, and is not intended to specify the present invention. Other embodiments within the scope of the claims are equally applicable.

The electronic device of this embodiment will be described by applying it to a notebook personal computer. FIG. 1 is a front view showing the main part of a notebook personal computer. FIG. 2 is a side view of FIG.

As shown in FIGS. 1 and 2, the notebook personal computer 1 includes a first housing 10 and a second housing 20, and the first housing 10 and the second housing 20 are opened and closed by a pair of left and right hinges 30L and 30R. It is a foldable type that is pivotally supported. This opening / closing angle can be maintained at an angle desired by the user in the range of 0 to 180 degrees.

The first housing 10 includes a liquid crystal panel 11, light emitting means 12, and adjusting means 13. The light emitting means 12 is a pair of left and right infrared light emitting diodes 121L, 12 that emit infrared rays of about 750 nm.
1R and a pair of left and right lenses 122L and 122R. Infrared light emitting diode 121L
, 121R and lenses 122L, 122R have two sets for detecting a three-dimensional position.

The infrared rays from the infrared light emitting diodes 121L and 121R, which are point light sources, are converted into lenses 122L,
122R becomes parallel lines. The adjusting means 13 adjusts the direction of the infrared rays emitted from the light emitting means 12, and is supported by the first arm 131 so as to be slidable by the first housing and pivotally supported by the first arm 131. And a second arm 132 to which the light emitting means 12 is fixed.
Sliding of the first arm 131 is performed by an elliptical slip 131a provided on the first arm 131 and two shafts 133U and 133D fitted into the slip 131a.
By this sliding, the height of the user's eye 8 is adjusted so that the reflected light of the eye 8 can be received by the display panel. The second arm 132 is rotated by the shaft 134. This rotation
The direction of the infrared rays from the light emitting means 12 is directed toward the user's eye 8.

As described above, since the adjusting means for changing the irradiation position of the light emitting means is provided, the light receiving position of the reflected light of the eye can be easily adjusted.

FIG. 3 is a diagram showing a pixel configuration of the liquid crystal panel 11. The liquid crystal panel 11 is colored WUXG
A, which has 1920 pixels in the gate line direction (horizontal direction) and 1200 pixels in the source line direction (vertical direction). Each pixel is composed of three RGB sub-pixels.

The liquid crystal panel 11 is a vertical electric field system. 4 is an equivalent circuit showing the main part of the sub-pixel, FIG. 5 is a plan view showing the pattern of the sub-pixel, FIG. 6 is a cross-sectional view taken along line AA ′ of FIG.
FIG. 4 is a diagram illustrating an incident portion of external light.

In FIG. 4, each sub-pixel includes a light detection unit 112 that detects light and outputs a light amount (luminance) in addition to a liquid crystal alignment unit 111 that changes luminance by changing the alignment of liquid crystal.
The liquid crystal alignment unit 111 includes a first switching thin film transistor TFT1 and a first storage capacitor C1. The source terminal S1 of the first switching thin film transistor TFT1 is a source driver D
Connected to RV1, the gate terminal G1 is connected to the gate driver DRV2. The first storage capacitor C1 includes a first drain electrode (58 in FIG. 6) to which the drain terminal D1 of the first switching thin film transistor TFT1 is connected, a common electrode (58 in FIG. 6) connected to the common line,
It consists of the 1st insulating layer (60 of FIG. 6) formed in the meantime.

The light detection unit 112 includes a second switching thin film transistor TFT2, a second storage capacitor C2, and a third switching thin film transistor TFT3. The source terminal S2 of the second switching thin film transistor TFT2 is connected to the source driver DRV1, and the gate terminal G2 is connected to the optical gate driver DRV3. The second storage capacitor C2 includes a second drain electrode (61 in FIG. 6) to which the drain terminal D2 of the second switching thin film transistor TFT2 is connected, an optical gate electrode (62 in FIG. 6) connected to the optical gate driver DRV3, It consists of the 1st insulating layer (60 of FIG. 6) formed in the meantime. The source S3 of the third switching thin film transistor TFT3 is connected to the optical gate electrode (62 in FIG. 6), and the gate G3 is the gate driver DRV2.
And the domain terminal D3 is connected to the line-of-sight detection means 14 of FIG.

In FIG. 5, the gate line 51 extends in the horizontal direction, and the source line 52 extends in the vertical direction. Further, the common line 53 and the optical gate line 54 extend in the horizontal direction, and the light amount output line 55 extends in the vertical direction. In this embodiment, a rectangular region divided by the optical gate line 54 and the source line 52 is a sub-pixel region. In each subpixel region, a first switching thin film transistor TFT1, a second switching thin film transistor TFT2, and a third switching thin film transistor TFT3 are disposed. A gate terminal G1 of the first switching thin film transistor TFT1 is connected to the gate line 51.
Are connected to the gate terminal G3 of the third switching thin film transistor TFT3. The gate terminal G2 of the second switching thin film transistor TFT2 is connected to the optical gate line 54.
A source terminal S1 of the first switching thin film transistor TFT1 and a source terminal S2 of the second switching thin film transistor TFT2 are connected to the source line 52. The drain terminal D3 of the third switching thin film transistor TFT3 is connected to the light quantity output line 55.

The drain terminal D1 of the first switching thin film transistor TFT1 is a contact hole 5
6 to the pixel electrode 57. The first switching thin film transistor TFT
One drain terminal D1 extends to form a first drain electrode 58 having a large area. A common electrode 59 is formed at a position where the common line 53 extends and faces the first drain electrode 58. As shown in FIG. 6, a first insulating layer 60 is formed between the first drain electrode 58 and the common electrode 59, and the three layers form the first storage capacitor C1. The second switching thin film transistor T
A drain terminal D2 of FT2 extends to form a second drain electrode 61 having a large area. An optical gate electrode 62 is formed at a position where the optical gate line 54 extends and faces the second drain electrode 61. As shown in FIG. 6, the 1st insulating layer 60 is formed between the 2nd drain electrode 61 and the optical gate electrode 62, and it becomes the 2nd electrical storage capacity C2 by these 3 layers.

In FIG. 6, a gate line 51, a common line 53, and an optical gate line 54 are formed on the TFT glass plate 63 on the back side of the liquid crystal panel 11 (the lower side in FIG. 6). The gate line 51 includes a gate terminal G1 of the first switching thin film transistor TFT1, a third switching thin film transistor TF.
The gate terminal G3 of T3 is connected. A common electrode 59 is formed on the common line 53. On the optical gate line 54, the gate terminal G2 of the second switching thin film transistor TFT2 and the optical gate electrode 62 are formed.

Then, the first insulating layer 60 is formed so as to cover the gate line 51, the common line 53, and the optical gate line 54. A source line 52 and a light amount output line 55 are formed on the first insulating layer 60. The source line 52 is connected to the source terminal S1 of the first switching thin film transistor TFT1 and the source terminal S2 of the second switching thin film transistor TFT2. The light output line 55 has a third
The drain terminal D3 of the switching thin film transistor TFT3 is connected. Further, on the first insulating layer 60, the respective semiconductor layers H1, H are opposed to the three gate terminals G1, G2, G3.
2, H3 are formed. The semiconductor layers H1, H2, and H3 are made of, for example, amorphous silicon.
Source terminals S1, S2, S3 and drain terminal D1 through semiconductor layers H1, H2, H3, respectively.
, D2 and D3 are connected. A second drain electrode 61 is connected to the drain terminal D2 of the second switching thin film transistor TFT2. And the source line 52, the light quantity output line 55,
Gate terminals G1, G2, G3, source terminals S1, S2, S3 and drain terminals D1, D2,
A second insulating layer 64 is formed so as to cover D3. On the second insulating layer 64, as shown in FIG.
A pixel electrode 57 is formed. The pixel electrode 57 and the first switching thin film transistor TF
A contact hole 56 for electrically connecting the source terminal S1 of T1 is formed.

TF of CF (color filter) glass plate 65 on the surface side of liquid crystal panel 11 (upper side in FIG. 6)
A light blocking black matrix 66 is formed on the T glass plate 63 side. As shown in FIG. 7, the black matrix 66 has a display opening 66a (display portion) at a position facing the pixel electrode 57.
In addition, an opening for external light 66b (external light incident portion) is provided at a position facing the semiconductor layer H2 of the second switching thin film transistor TFT2. TFT matrix 6 of black matrix 66
A color filter 67 is formed on the third side, and a counter electrode 68 is formed on the TFT glass plate 63 side of the color filter 67. A liquid crystal element 69 is disposed between the pixel electrode 57 and the counter electrode 68.

A first polarizing plate 70 is disposed on the back side of the TFT glass plate 63, and a second polarizing plate 71 is disposed on the front side of the CF glass plate 65. And the backlight 72 is arrange | positioned at the back side of the 1st polarizing plate 70, and irradiates light toward the surface.

Due to the configuration of the display panel 11, the first switching thin film transistor TFT1 is
A liquid crystal element between the pixel electrode 57 and the counter electrode 68 is received by applying a gate drive signal from the gate driver DRV2 and a source drive signal from the source driver DRV1 and changing a voltage applied to the pixel electrode 57. The orientation of 69 is changed. As a result, the amount of light (luminance) emitted from the backlight 72 through the display openings 66a of the black matrix 66 changes.

In the second switching thin film transistor TFT2, when external light from the external light opening 66b is incident on the semiconductor layer H2 in response to the application of the gate drive signal from the optical gate driver DRV3, the source terminal S2 and the drain terminal D2 become conductive. Then, a current corresponding to the amount of light (brightness) flows, charges are accumulated in the second storage capacitor C2, and a voltage corresponding to the accumulated charge amount is generated.

The third switching thin film transistor TFT3 receives the application of the gate drive signal from the gate driver DRV2, and outputs the voltage of the second storage capacitor C2 to the line-of-sight detection means 14 in FIG.

FIG. 8 is a block diagram showing the main part of the notebook personal computer 1, FIG. 9 is a front view of the eye, and FIG. 10 is a cross-sectional view of the eye. In FIG. 8, the infrared rays emitted from the light emitting means 12 are reflected by the eyes. The reflected light is reflected on the light detection unit 112 (TFT2, C2)
2, the voltage detected by the TFT 3) and corresponding to the amount of reflected light is input to the line-of-sight detection means 14.
The line-of-sight detection means 14 calculates the line of sight based on the received signal from the light detection unit 112, and the control means 1
5 is output. The control means 15 displays the light receiving position display O set by operating the light receiving position display key.
When in the N mode, the driver 113 is controlled to display the light receiving position of the eye 8 on the liquid crystal panel 11. In this display, an applied voltage based on the output voltage of the third switching thin film transistor TFT3 is output to the first switching thin film transistor TFT1 in the same sub-pixel. As a result, an eye image is displayed as shown in FIG. The driver 113 includes the aforementioned source driver DRV1, gate driver DRV2, and optical gate driver DRV3. In addition, FIG.
As shown in FIG. 2, the control means 15 controls the driver 17 to display an icon (
(Eye pointer) is displayed.

The line of sight detection method of the line of sight detection means 14 will be described. The line-of-sight detection means 14 is disclosed in Patent Document 2.
The line-of-sight direction is calculated by the method described in (1). The contour of the pupil is detected from the signal from the light detection unit 111 and the center thereof is calculated. In the detection of the pupil, the pupil is darker than the iris or sclera, so that the image is segmented, and an elliptical area darker than the surrounding is defined as the pupil. Next, a Purkinje image (see FIG. 9) that is a reflection image on the corneal surface is detected. In the detection of Purkinje image,
A bright spot located in the vicinity of the pupil is defined as a Purkinje image, and the position of the three-dimensional Purkinje image is obtained from images of two left and right infrared rays. The corneal curvature center is calculated from the position of the Purkinje image using the previously stored corneal curvature radius. Then, a direction vector passing through the center of the pupil and the center of the corneal curvature is obtained and used as the line of sight.

FIG. 11 is a flowchart showing the operation of the control means 15 of FIG. The control means 15 is EE
Display control is performed based on a program written in a PROM (not shown). The variable m is stored in an internal register. m = 0 indicates a mode in which the display position of received light is not displayed,
m = 1 indicates a mode for displaying the display position of received light. The initial value of m is 0 (step S1
). When the light receiving position display key 16 is pressed (Yes in Step S2), if the variable m is 0 (Yes in Step S3), the variable m is changed to 1 (Step S4) and the driver 17 is controlled. Thus, the light receiving position is displayed on the liquid crystal panel 11 (step S5). If the variable m is 1 (No in step S3), the variable m is changed to 0 (step S6), and the light receiving position is not displayed on the liquid crystal panel 11 by controlling the driver 17 (step S7).
That is, the display of the light reception display position is switched ON / OFF by the light reception position display key 16. The light receiving position is displayed by applying an applied voltage based on the output voltage of the TFT substrate for detecting external light to the first switching thin film transistor TFT1 in the same subpixel.

The liquid crystal panel of Patent Document 4 includes a light detection element. However, since the light detection element is formed outside the display area, the light receiving area is narrow. In contrast, the liquid crystal panel of the present invention has T in the sub-pixel.
By forming an FT photodetecting element, light can be received in a wide area of the display panel. The light detection element is a TFT made of the same material as the TFT that changes the orientation of the liquid crystal element.
Therefore, an increase in the number of manufacturing steps can be avoided.

Further, in order to display the light receiving position of the eye, it is possible to prevent the light reception failure of the eye due to the opening angle of the notebook personal computer 1. Further, as shown in FIG. 4, the source terminal S2 of the second switching thin film transistor TFT2 for light sensing is connected to the same source driver DRV1 as the source terminal S1 of the first switching thin film transistor TFT1 for liquid crystal alignment,
The gate terminal G3 of the third switching thin film transistor TFT3 for light output is the same gate driver D as the gate terminal G1 of the first switching thin film transistor TFT1 for liquid crystal alignment.
Since it is connected to RV2, it is easy to display the light receiving position of the eye with the same subpixel as the light receiving.

As described above, the gaze detection method of the present invention is limited to a method of detecting the gaze direction from the center of the pupil and the position of the Purkinje image, assuming that the gaze direction is a vector connecting the pupil and the corneal curvature center. Instead, for example, the black eye sclera reflection method for detecting the cornea and sclera as in Patent Document 1 may be used.

Moreover, although the above-mentioned Example was a vertical electric field type liquid crystal panel, it can be applied to a horizontal electric field type liquid crystal panel, and can also be applied to an organic EL (electroluminescence) panel.

It is a front view which shows the principal part of the electronic device of this invention. It is a side view of FIG. It is a figure which shows the pixel arrangement | sequence of a liquid crystal panel. It is a figure which shows the equivalent circuit of the principal part of a liquid crystal panel. It is a top view which shows the principal part of a liquid crystal panel. FIG. 6 is a cross-sectional view taken along the line A-A ′ of FIG. 5. It is a top view which shows the incident part of external light. It is a block diagram which shows the structure of the principal part of an electronic device. It is a front view of eyes. It is sectional drawing of an eye. It is a flowchart which shows operation | movement of the principal part of a control means. It is a figure which shows the conventional equivalent circuit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Notebook personal computer 10 1st housing | casing 11 Liquid crystal panel 111 Light detection part 112 Liquid crystal aligning part 113 Driver 12 Light emission means 121L, 121R Infrared light emitting diode 122L, 122R Lens 13 Adjustment means 131 1st arm 132 2nd arm 14 Line of sight Detection means 15 Control means 16 Light receiving position display key 20 Second housing 30L, 30R Hinge 51 Gate line 52 Source line 53 Common line 54 Optical gate line 55 Light quantity output line 56 Contact hole 57 Pixel electrode 58 First drain electrode 59 Common electrode 60 First insulating layer 61 Second drain electrode 62 Optical gate electrode 63 TFT glass plate 64 Second insulating layer 65 CF glass plate 66 Black matrix 67 Color filter 68 Counter electrode 69 Liquid crystal element 70 First polarizing plate 71 Second polarization 72 backlight C1, C2 first charge capacity DRV1 source driver DRV2 gate driver DRV3 optical gate driver D1, D2, D3 drain terminal G1, G2, G3 gate terminals S1, S2, S3 source terminal TFT1, TFT2, TFT3 switching TFT

Claims (6)

Having a plurality of sub-pixels for brightness control;
The sub-pixel includes a first TFT that changes luminance according to an applied voltage, a second TFT that receives external light, a charge accumulation unit that accumulates charge according to the amount of light received by the second TFT, and the charge A display panel comprising: a TFT substrate on which a third TFT that outputs a voltage corresponding to the amount of electric charge accumulated in an accumulation unit is formed. 2. The source terminal of the first TFT and the source terminal of the second TFT are connected to the same source driver, and the gate terminal of the first TFT and the gate terminal of the third TFT are connected to the same gate driver. The display panel described in 1. An electronic device having a display panel having a plurality of sub-pixels for which brightness control is performed,
The sub-pixel includes a first TFT that changes luminance according to an applied voltage, a second TFT that receives external light, a charge storage unit that stores charges according to the amount of light received by the second TFT, and the charge storage A TFT substrate formed with a third TFT that outputs a voltage corresponding to the amount of charge accumulated in the part,
Light emitting means for irradiating light toward the user's eyes, line of sight detecting means for calculating the line of sight based on the output voltage of the third TFT, and the position of the reflected light of the eye received by the display panel on the display panel An electronic apparatus having a display panel, comprising control means for displaying. 4. The electronic apparatus having a display panel according to claim 3, wherein the control means outputs an applied voltage based on an output voltage of the third TFT to the first TFT in the same sub-pixel. 5. A first housing having the display panel, a second housing, and a hinge that pivotally supports the first housing and the second housing so as to be openable and closable. An electronic device having the display panel described in 1. 6. The electronic apparatus having a display panel according to claim 5, further comprising an adjusting unit that varies an irradiation position of the light emitting unit.

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