JP2002116429A - Liquid crystal display device provide with position detecting function - Google Patents

Abstract

(57) [Problem] To provide a liquid crystal display device which is inexpensive, simple, durable, and has a highly accurate position detection function without lowering visibility. SOLUTION: In a liquid crystal display device in which liquid crystal is sealed between a thin film transistor array substrate and a counter substrate,
A light-receiving element is provided on the thin film transistor array substrate along the outer periphery of the display area, light-emitting elements are provided at two corners of the outer periphery of the display area on the front side of the counter substrate, and light from the light-emitting element is incident on the light-receiving element. A reflector was provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a position detecting function, and more particularly to an inexpensive and simple method of adding a high-precision position detecting function to an active matrix type liquid crystal display device. And

[0002]

2. Description of the Related Art Devices for inputting and selecting menus by touching a display screen such as a liquid crystal display device or a CRT with a fingertip or a pen tip are widely used in ATMs of banks and ticket vending machines at stations. I have. In recent years, personal computers, portable information terminals, and the like also have such a function of inputting with a finger or a pen or selecting a menu, and provide a more user-friendly interface.

There are several methods for detecting the contact position of a pen tip or a finger tip.

[0004] For example, pages 49 to 52 of the monthly display 'January 1999' include infrared rays L as shown in FIG.
A light-emitting unit 13 composed of an ED and a light-receiving unit 14 composed of a phototransistor are provided, and the position of the light-shielding object 305 is detected by blocking light (infrared light) from the light-emitting unit 13 by a light-shielding object 305 such as a pen tip or a fingertip. The method is shown (conventional method 1).

In the conventional method 1, a light emitting unit 13 composed of an infrared LED and a light receiving unit 1 composed of a phototransistor are used.
4 is provided separately from the display device on the outer periphery of the display area of the display device, so that the element spacing cannot be made close and precise position detection is impossible. Further, the cost is increased by attaching the light emitting unit 13 and the light receiving unit 14 externally. Although not shown in FIG. 13, a mechanism for controlling the operation time of each light emitting unit 13 and light receiving unit 14 is further required so that the pair of opposing light emitting units 13 and light receiving unit 14 operate sequentially. .

On pages 44 to 48 of the monthly display 'January 1999', two transparent conductive films 21 and 22 as shown in FIG. The two transparent conductive films 21 and 22 are contacted and short-circuited by the pressure on the screen by the fingertip or the pen 505, and the short-circuited portion is derived from a change in the resistance value between the two transparent conductive films 21 and 22 and A position detection method of a so-called resistive film system for detecting the position of the pen 505 is shown (conventional method 2).

In the conventional method 2, the transparent conductive film 21,
22 has a light transmittance of not 100%, and the transparent conductive films 21 and 22 generate a specular reflection component on the surface of the display screen, thereby deteriorating the visibility of the screen.

[0008]

As described above, in the conventional method 1, in order to add a position detecting function, it is necessary to install a light emitting element and a light receiving element in a form added to the outside of the display device. , Which led to higher costs. In addition, since it is difficult to make the distance between the elements close, it is difficult to improve the position detection accuracy, and is mainly used as a touch sensor, not for character input.

Further, in the conventional method 2, since the film is attached to the surface of the screen, the visibility of the screen is significantly reduced. Further, in this method, since the position is detected by crushing the film, the method is inferior to the conventional method 1 in terms of durability.

The present invention solves the above problems, and is inexpensive and simple without lowering visibility.
It is an object of the present invention to provide a liquid crystal display device having excellent durability and having a highly accurate position detection function.

[0011]

According to the present invention, in a liquid crystal display device in which liquid crystal is sealed between a thin film transistor array substrate and a counter substrate, a light receiving element is provided on the thin film transistor array substrate along an outer periphery of a display area. A light emitting element is provided at two corners on the outer side of the display area on the front side of the counter substrate, and a reflecting mirror for making light of the light emitting element incident on the light receiving element is provided.

The light receiving element is formed simultaneously with the manufacture of the thin film transistor array substrate.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows the overall configuration of the reflection type liquid crystal display device of the present embodiment, wherein FIG. 2A shows a cross section thereof, and FIG. 2B shows a diagram viewed from above.

A liquid crystal is sealed between a thin film transistor array substrate (TFT array substrate) 2 and a counter substrate 1 to constitute a liquid crystal display device. Information such as images and text
It is displayed in a display area 8 surrounded by a broken line in the figure.

A large number of light receiving elements are arranged on the thin film transistor array substrate 2 along three sides on the outer periphery of the display area 8 to form a light receiving element array 4. On the other hand, on the upper surface of the opposing substrate 1 (upper side of FIG. 2A), the light emitting elements 3 are respectively provided at both ends of one side of the outer periphery of the display area 8 where the light receiving elements (light receiving element array 4) are not arranged. Are located. Further, a reflection mirror 5 is provided on the upper surface of the counter substrate 1 and immediately above the light receiving element (light receiving element array 4).
Light 7 emitted from the light emitting element 3 is reflected by the reflecting mirror 5 and enters the light receiving element (light receiving element array 4).

The thin film transistor array substrate 2 is also provided with a mechanism for binarizing the output of each light receiving element in accordance with the presence or absence of light, and outputting it to a circuit for position detection.

An outline of the position detecting method according to the present invention will be described.

First, one of the light emitting elements 3 (referred to as a first light emitting element) is turned on, and the light receiving elements on three sides are turned on.
Next, the first light emitting element is turned off, the other light emitting element 3 (second light emitting element) is turned on, and the light receiving elements on three sides are turned on. The light from the light emitting element 3 is reflected by the reflecting mirror 5 and enters the light receiving element. However, when a light shield such as a fingertip or a pen tip is on the opposing substrate 1, a shadow is formed and some light receiving elements emit light. Does not enter. The position of the shadow is detected from the presence or absence of light incident on each light receiving element, and the position of the shadow formed by the lighting of the first light emitting element and the position of the shadow formed by the lighting of the second light emitting element are determined based on the position of the shadow. Calculate the position.

The presence or absence of light incident on each light receiving element can be detected by the circuit having the configuration shown in FIG.

When a pulse is input to the power supply 208, the TFT
The switch 206 is turned on, and the potential of the capacitor 210 is reset to the reset potential supplied from the power supply 207. The pulse supplied from the power supply 201 is
When the voltage is transmitted to the TFT switch 204 due to the decrease in resistance, the potential applied from the power supply 202 is written to the capacitor 210. The decrease in the resistance of the light receiving element 203 is caused by receiving light. When light does not enter the light receiving element 203, the potential of the capacitor 210 remains at the reset potential supplied from the power supply 207.

Shift register 200 and TFT switch 2
Using 09, the potential of the capacitor 210 is sequentially read from the terminal 205. From the potential of the capacitor 210, each light receiving element 203
It is possible to detect the presence or absence of light incident on the device.

Referring to FIG. 4, a method for manufacturing the thin film transistor array substrate 2 according to the present embodiment will be described.

FIG. 4 shows a cross section of the thin film transistor array substrate 2 and shows two polycrystalline thin film transistors 1.
14 and 115 and the light receiving element 113 are shown. The light receiving element 113 and the thin film transistor 114 correspond to the light receiving element 203 and the TFT switch 204 in FIG. 3, respectively, and the thin film transistor 115 is for applying a voltage to and driving a liquid crystal.

The thin film transistor array substrate 2 has an insulating layer 101 formed on a glass substrate 100, and further includes, for example, a polycrystalline silicon film 102,
Polycrystalline thin film transistors 114 and 115 each comprising a gate insulating film 103 composed of an O ₂ film, a gate electrode 104 composed of a metal film, and source / drain regions 105 in which phosphorus ions are implanted into the polycrystalline silicon film 102 are formed.
Further, an interlayer insulating film 107 made of a SiO ₂ film or the like is formed so as to cover the thin film transistors 114 and 115.

On the interlayer insulating film 107,
An amorphous silicon film 108 is formed below the portion where the thin film transistor is not formed. A metal film 106 is formed directly under the amorphous silicon film 108 and on the gate insulating film 103 in advance by the thin film transistor 114,
When the gate electrode 104 of 115 is formed, it is formed at the same time. Ions are implanted into the electrode forming portion 112 of the amorphous silicon film 108.

The gate electrode 10 of the thin film transistor 114
4, a contact hole penetrating the upper interlayer insulating film 107 is formed, and a contact hole penetrating the upper interlayer insulating film 107 and the gate insulating film 103 is formed on the thin film transistor 115 source / drain region 105.

In order to connect the thin film transistor 114 and the amorphous silicon film 108, a metal film 109 connecting the contact hole and the electrode forming portion 112 of the amorphous silicon film 108 is formed. An insulating film 110 made of SiN is formed on the above structure. Further, a metal film 111 serving as a reflective electrode is formed on the uppermost layer. The reflective electrode and the thin film transistor 115 are connected by a through hole provided in the insulating film 110.

With reference to FIG. 5, how shadows are formed by the light emitting element and the light shield will be described. FIG. 5 shows FIGS. 1 and 2
FIG. 2 is a schematic view of the liquid crystal display device of FIG.

Light emitting diodes are provided as the light emitting elements 303a and 303b at the upper right and upper left corners of the display area 301 of the liquid crystal display device, respectively. The wavelengths of both light emitting diodes are the same. Both light-emitting diodes are turned on alternately.
The light intensity of the light emitting diode is set to 600 mcd, and the emission angle from the light emitting diode is extremely small in the vertical direction of the screen and 90 ° or more in the horizontal direction of the screen. Assuming that the light receiving area of the light receiving element is 1 mm ² and the distance between the light emitting diode and the light receiving element is 40 mm, the illuminance at the light receiving element is about 370 lx. It is assumed that the light receiving element can detect the incident light of this illuminance.

In the outer periphery of the display area 301, a large number of light receiving elements are arranged along three sides of a right side, a lower side, and a left side to form a light receiving element array 304, and a reflecting mirror is disposed immediately above the light receiving element array.
Light from the upper right light emitting element 303a is reflected by the reflecting mirror,
The light reaches the light receiving elements on the left side and the lower side.
When the light-shielding object 305 appears on 1, a shadow is formed, and some light-receiving elements do not reach the light. In FIG. 5A, a hatched portion 306 is a portion that is illuminated by light, and a hatched portion 307 is a shadow and is a light receiving element to which light does not reach.

Similarly, the light from the upper left light emitting element 303b is reflected by the reflecting mirror and reaches the light receiving elements on the right side and the lower side, but there is a light receiving element to which the light does not reach due to the shadow of the light shield 305. In FIG. 5B, a hatched portion 306 is a portion that is illuminated by light, and a hatched portion 307 is a shadow and is a light receiving element to which light does not reach.

The boundary between the shadow portion and the light arrival portion is detected from the presence or absence of light incident on each light receiving element, and the position of the center of the shadow on each side is calculated from the boundary position.

The light receiving element is operated only in accordance with the lighting time of each light emitting diode.

FIG. 6, FIG. 7 and FIG.
The relationship between the position where the shadow is formed by 3a and 303b and the position of the light shield 305 is shown. 6 shows a case where a shadow is formed on each of the left and right sides, FIG. 7 shows a case where one side of the shadow is formed on the lower side, and FIG. 8 shows a case where the other side is formed on either of the left and right sides. This is a case where both shadows are formed on the lower side. 6, 7, and 8,
p and q represent the dimensions in the vertical and horizontal directions of the display area in FIG. 5, respectively.

As shown in FIG. 6, when a shadow by the light emitting element 303a is formed at a distance a from the upper end of the left side and a shadow by the light emitting element 303b is formed at a distance b from the upper end of the right side, The coordinates (X, Y) of the light shield 305 are calculated by (Equation 1). X = pa / (a + b) Y = ab / (a + b) (Equation 1)

As shown in FIG. 7, when a shadow by the light emitting element 303a is formed at a distance d from the left end of the lower side and a shadow by the light emitting element 303b is formed at a distance c from the upper end of the right side, The coordinates (X, Y) of the light shield 305 are calculated by (Equation 2). X = cpq / (p (pd) + cq) Y = ab / (a + b) (Equation 2)

As shown in FIG. 8, when a shadow by the light emitting element 303a is formed at a distance e from the left end of the lower side and a shadow by the light emitting element 303b is formed at a distance f from the right end of the lower side, The coordinates (X, Y) of the light shield 305 are calculated by (Equation 3). X = pf / (pe + f) Y = pq / (pe + f) (Equation 3)

The time given to the light receiving element for detecting the shadow by the light emitting element is set within 0.1 sec. When the light emitting element 303a arranged at the upper right corner emits light, all the light receiving elements located on the left side and the lower side are This 0.1 sec
During c, binary information corresponding to the presence or absence of light is recorded in the corresponding capacitor 210 (see FIG. 3). Individual capacity 21
The binary information recorded in 0 is sequentially read out by the shift register 200 composed of a polycrystalline silicon thin film transistor. From the terminal 205, information on the presence or absence of light incident on each light receiving element is sent out on one line. Subsequently, the light emitting element 303b arranged at the upper left corner emits light, and all the light receiving elements located on the right side and the lower side also emit light for 0.1 second.
Binary information corresponding to the presence or absence of light during c is recorded in the corresponding capacitor 210. The recorded information is read by the shift register 200 and sent out from the terminal 205 on the same line.

As described above, information on the presence or absence of light incident on each light receiving element is output as data on one signal line arranged in time series. From the output data, detection of the boundary between the shadow portion and the portion where light is incident, calculation and storage of the center position of the shadow, and the above-mentioned FIGS. 6 (Equation 1), 7 (Equation 2) and FIG.
Classification as to which of the cases of (Expression 3) belongs and calculation of the position coordinates of the shielding object by (Expression 1), (Expression 2) or (Expression 3) are performed.

According to the present embodiment, since the light receiving element is provided on the thin film transistor array substrate, there is no need to provide an external light receiving element, and an inexpensive and high-performance liquid crystal display device with a position detecting function can be obtained. it can.

Further, since only two light emitting elements conventionally required are required, a liquid crystal display device having a position detecting function can be obtained at low cost.

Further, since the light receiving element is formed simultaneously with the manufacture of the thin film transistor array substrate and using the same semiconductor manufacturing process technology, an increase in the number of manufacturing steps can be suppressed, and a low-cost and highly reliable position detecting function can be realized. As a result, a liquid crystal display device can be obtained, and the density of light receiving elements can be increased (the arrangement interval can be reduced), so that highly accurate position detection can be performed.

Further, since the light receiving element is directly connected to the TFT switch composed of a polycrystalline silicon thin film transistor, it is possible to determine in a short time whether light is incident on the light receiving element.

As shown in FIG. 2A, a light guide 6 is provided at the light exit of the light emitting element 3 so that only the component parallel to the display screen (opposite substrate 1) is output from the light guide. Thus, a more accurate position detection may be performed.

Further, a light guide 6 is provided above the light receiving element (light receiving element array 4) so that only light from a specific direction is incident on the light receiving element. Position detection can be performed.

Further, by applying an anti-reflection process to a portion outside the display area 8 and where no reflecting mirror is provided, unnecessary reflection can be prevented and visibility can be improved.

Further, according to the present invention, unlike the conventional method 1, it is not necessary to sequentially operate the pair of opposing light emitting units and light receiving units, so that an electrical switching function for externally turning on and off the light receiving element is provided. A high-performance liquid crystal display device with a position detection function can be obtained at a low cost without providing the liquid crystal display device.

However, by sequentially turning on and off each light receiving element of the light receiving element array, it is possible to further improve the accuracy of position detection. In this case, if each light receiving element is always operated, and liquid crystal positioned above each light receiving element is used as a shutter to control transmission / blocking of light, instead of turning on / off the light receiving element, A mechanism for turning on and off each light receiving element is unnecessary, and a liquid crystal display device with a position detection function that is inexpensive, has high reliability, and has high performance can be obtained. The on / off of the liquid crystal shutter is performed by changing the voltage applied to the liquid crystal at the position corresponding to each light receiving element.

Embodiment 2 In Embodiment 1, light-emitting elements are provided at the upper right and upper left corners of the display area of the liquid crystal display device, and the light-receiving elements are arranged along three sides of the left, lower, and right sides of the display area. A light receiving element array) and a reflecting mirror were arranged.

On the other hand, in the present embodiment, light emitting elements are arranged at two opposing corners (for example, upper right corner and lower left corner) of the display area, and light receiving elements (light receiving element array) are arranged on four sides of the display area.
And a reflector.

The liquid crystal display of this embodiment will be described with reference to FIG. FIG. 9 is a top view of the liquid crystal display device of the present embodiment, and FIG. 2B in the first embodiment.
Corresponding to

On the thin film transistor array substrate, a large number of light receiving elements are arranged along the four sides on the outer periphery of the display area 8,
The light receiving element array 4 is formed. On the other hand, on the upper surface of the counter substrate 1, the light emitting elements 3 are arranged at the upper right corner and the lower left corner of the outer periphery of the display area 8. Further, a reflection mirror 5 is provided on the upper surface of the counter substrate 1 and immediately above the light receiving element (light receiving element array 4). Light 7 emitted from the light emitting element 3 is reflected by the reflecting mirror 5 and enters the light receiving element (light receiving element array 4).

In this embodiment, light from the light emitting element 3 at the upper right corner is incident on the light receiving elements on the left and lower sides, and light from the light emitting element 3 on the lower left corner is incident on the light receiving elements on the right and upper sides. That is, only light from one light emitting element always enters each light receiving element, and no light from the other light emitting element enters. Since the source of the light incident on each light receiving element is specified, the position of the light shield can be easily calculated. Also, since the two light emitting elements may be constantly turned on,
Production of a supply signal to the light emitting element is facilitated.

Third Embodiment In the first embodiment, a light-emitting element that emits light of the same wavelength is provided at the upper right corner and the upper left corner of the display area of the liquid crystal display device, and three sides of the left, lower, and right sides of the display area are provided. A light-receiving element (light-receiving element array) and a reflecting mirror were arranged along.

On the other hand, in the present embodiment, light emitting elements that emit light of different wavelengths are provided at the upper right corner and the upper left corner of the display area of the liquid crystal display device, and at least two sets of light receiving elements are provided at the lower side of the display area. (Light receiving element array), and these two sets of light receiving elements (light receiving element array)
It is characterized by including filters that transmit light of different wavelengths.

The liquid crystal display of this embodiment will be described with reference to FIG. FIG. 10 is a view of the liquid crystal display device of the present embodiment as viewed from above, and FIG.
This corresponds to (b).

On the thin film transistor array substrate, a large number of light receiving elements are arranged along three sides on the outer periphery of the display area 8 to form the light receiving element array 4. At least on the lower side, two sets of light receiving elements (light receiving element array 4) each having a filter that transmits light of a different wavelength.
a, 4b) are arranged. On the other hand, on the upper surface of the counter substrate 1,
At the upper right corner and the upper left corner of the outer periphery of the display area 8, the light emitting elements 3 that emit light having different wavelengths are arranged. Further, a reflection mirror 5 is provided on the upper surface of the counter substrate 1 and immediately above the light receiving element (light receiving element array 4). Light 7 emitted from the light emitting element 3 is reflected by the reflecting mirror 5 and enters the light receiving element (light receiving element array 4).

In this embodiment, the light from the upper right corner light emitting element 3 enters the left and lower light receiving elements, and the light from the upper left corner light emitting element 3 enters the right and lower light receiving elements. At this time, one of the two sets of light receiving elements (light receiving element array) arranged on the lower side receives only light from one light emitting element by the filter. In other words, for example, the light wavelength of each light emitting element and the light reception are such that the light receiving element array 4a receives only the light from the light emitting element at the upper right corner and the light receiving element array 4b receives only the light from the light emitting element at the upper left corner. The wavelength of light transmitted through a filter provided in the element (light receiving element array) is selected in advance.

With this configuration, only light from one light emitting element is always incident on each light receiving element, and light from the other light emitting element is not incident. Since the source of the light incident on each light receiving element is specified, the position of the light shield can be easily calculated. Further, since the two light emitting elements may be constantly turned on, it is easy to produce a supply signal to the light emitting elements.

In this embodiment, the thin film transistor of the liquid crystal display device is an amorphous silicon thin film transistor. A method for manufacturing the thin film transistor array substrate according to the present embodiment will be described with reference to FIG.

FIG. 11 shows a cross section of a thin film transistor array substrate.
14 and 115 and the light receiving element 113 are shown. The light receiving element 113 and the thin film transistor 114 correspond to the light receiving element 203 and the TFT switch 204 in FIG. 3, respectively, and the thin film transistor 115 is for applying a voltage to and driving a liquid crystal.

In the thin film transistor array substrate, an insulating layer 101 is formed on a glass substrate 100, and a gate electrode 104 made of a metal film, a gate insulating film 103 made of a SiO ₂ film, an amorphous silicon film 108, an amorphous silicon film 108, An electrode forming portion 112 in which ions are implanted into the silicon film 108, and amorphous thin film transistors 114 and 115 including source / drain electrodes formed from the metal film 109 are formed.
Further, an interlayer insulating film 107 is formed so as to cover the thin film transistors 114 and 115. Then, a metal film 111 serving as a reflective electrode is formed on the uppermost layer. The reflective electrode and the thin film transistor 115 are connected by a through hole provided in the interlayer insulating film 107.

The structure of the light receiving element 113 is as follows, except that the amorphous silicon film 108 is not shielded from light by the metal film 111.
It is exactly the same as the amorphous thin film transistors 114 and 115. Therefore, the thin film transistors 114, 115
At the same time as the formation of
Is also formed.

Since the light receiving element can be formed simultaneously with the thin film transistor for driving the liquid crystal in the same step, the number of manufacturing steps is not increased as compared with the conventional liquid crystal display device without a position detecting function. In addition, it is possible to obtain an inexpensive and highly reliable liquid crystal display device with a position detection function, and it is possible to increase the density of light receiving elements (reduce the arrangement interval), thereby enabling highly accurate position detection. A liquid crystal display device with a position detection function can be obtained.

Fourth Embodiment FIG. 12 shows an example in which the liquid crystal display device with a position detecting function according to each embodiment of the present invention is applied to a portable device. FIG.
Denotes a mobile phone, a housing 404 is provided with a number button 402, an operation button 403, and a liquid crystal display device 401 with a position detection function according to the present invention, and a pen 405.
Allows input and menu selection.

Embodiment 5 In the above embodiments, the reflection type liquid crystal display device has been described as an example. However, the present invention can be applied to other types of liquid crystal display devices such as a transmission type or a transflective type. It is of course possible to apply.

The arrangement of the light emitting element and the light receiving element and the type of the thin film transistor are not limited to the combinations described in the above embodiments, but may be other combinations.

[0069]

According to the present invention, there is no need to separately provide a light receiving element outside the liquid crystal display device, and a liquid crystal display device with a high-performance position detecting function can be obtained at low cost.

According to the present invention, by making the light wavelengths of the two light emitting elements different, it is not necessary to operate each light emitting element intermittently, and it is possible to reduce the cost without providing an external electrical switching function. Thus, a high-performance liquid crystal display device with a position detection function can be obtained.

According to the present invention, by arranging two light emitting elements at opposite corners, it is possible to obtain a high-performance liquid crystal display device with a position detecting function at low cost without having an external electrical switching function. it can.

According to the present invention, by using the liquid crystal shutter to turn on and off the light receiving element, it is possible to provide an inexpensive, highly reliable and highly accurate position detection without providing an external electrical switching function. A liquid crystal display device with a possible position detection function can be obtained.

According to the present invention, a high-performance liquid crystal display device with a position detecting function can be obtained at low cost by using a light emitting element having good luminous efficiency.

According to the present invention, a liquid crystal display device having a position detecting function with lower power consumption can be obtained by intermittently lighting two light emitting elements.

According to the present invention, by providing a light guide at the light exit of the light emitting element, it is possible to obtain a high-performance liquid crystal display device with a position detecting function having a lower error probability.

According to the present invention, by providing the light guide above the light receiving element, it is possible to obtain a liquid crystal display device having a high-performance position detecting function with a lower error probability.

According to the present invention, with a simple optical system configuration,
A high-performance liquid crystal display device with a position detection function can be obtained.

According to the present invention, the light-receiving element can be formed in the same step as the thin-film transistor for driving the liquid crystal in the same step. Thus, a liquid crystal display device with a position detection function that is inexpensive and highly reliable can be obtained without increasing the number of pixels.

According to the present invention, the presence or absence of light incident on the light receiving element can be detected in a short time, and high-speed position detection is possible.

According to the present invention, unnecessary reflection at the outer periphery of the display function portion can be reduced, and a liquid crystal display device with a position detection function having excellent visibility can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a cross section and a top surface of the liquid crystal display device of FIG.

FIG. 3 is a diagram showing a configuration of a drive circuit of a light receiving element according to the present invention.

FIG. 4 is a cross-sectional view schematically showing a configuration of a thin film transistor array substrate of the liquid crystal display device according to the present invention.

FIG. 5 is a diagram illustrating a relationship between light from a light emitting element and a light receiving element that is shadowed by a light shielding object.

FIG. 6 is a diagram illustrating the relationship between the center position of a shadow and the position coordinates of a light shielding object.

FIG. 7 is a diagram illustrating the relationship between the center position of a shadow and the position coordinates of a light shield.

FIG. 8 is a diagram illustrating the relationship between the center position of a shadow and the position coordinates of a light shielding object.

FIG. 9 is a top view of a liquid crystal display device according to another embodiment of the present invention.

FIG. 10 is a top view of a liquid crystal display device according to still another embodiment of the present invention.

FIG. 11 is a cross-sectional view schematically illustrating a configuration of a thin film transistor array substrate of a liquid crystal display device according to the present invention.

FIG. 12 is a diagram showing an example in which a liquid crystal display device with a position detection function according to the present invention is applied to a portable device.

FIG. 13 is a diagram for explaining a conventional position detection method (conventional method 1).

FIG. 14 is a diagram for explaining a conventional position detection method (conventional method 2).

[Explanation of symbols]

1 counter substrate, 2 thin film transistor array substrate, 3
Light emitting element, 4 light receiving element array, 5 reflecting mirror, 6 light guide, 7 light, 8 display area, 9 regular reflecting mirror, 13 light emitting section, 14 light receiving section, 18 display area, 21 transparent conductive film, 22 transparent conductive film, 100 glass substrate, 101
Insulating layer, 102 polycrystalline silicon film, 103 gate insulating film, 104 gate electrode, 105 source / drain region, 107 interlayer insulating film, 108 amorphous silicon film,
109 metal film, 110 insulating film, 111 reflective electrode, 1
12 electrode forming part, 113 light receiving element, 114 thin film transistor, 115 thin film transistor, 200 shift register, 201 power supply, 202 power supply, 203 light receiving element, 204 TFT switch, 205 power supply, 206
TFT switch, 207 power supply, 208 power supply, 20
9 TFT switch, 301 display area, 303a light emitting element, 303b light emitting element, 304 light receiving element array,
305 light shield, 306 part illuminated by light, 30
7 shadow, 401 liquid crystal display device with position detection function, 40
2 number button, 403 operation button, 404 housing,
405 pen, 505 pen.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) G06F 3/033 360 G06F 3/033 360E 5B087 G09F 9/00 366 G09F 9/00 366A 5F049 H01L 31/10 H01L 31/12 D 5F089 31/12 31/10 A 5G435 F-term (Reference) 2F065 AA03 BB05 CC00 CC16 CC25 FF02 FF09 GG13 HH15 JJ01 JJ05 JJ25 LL00 LL12 LL30 QQ25 QQ26 QQ27 QQ28 2H088 EA33 HA28 TA2017FAX2 FA48Y FD03 FD04 GA11 GA13 LA30 2H093 NA71 NA74 NA76 ND60 5B087 AA02 AA04 CC02 CC34 5F049 MA02 MB03 NA20 NB10 RA02 RA10 SS03 TA20 UA01 5F089 BA02 BB09 BC02 BC07 BC11 CA21 FA06 GA08 GA10 5G09 BB12 DD01 DD01

Claims (12)

[Claims] 1. A liquid crystal display device in which liquid crystal is sealed between a thin film transistor array substrate and a counter substrate, wherein a light receiving element is provided on the thin film transistor array substrate along three sides of an outer periphery of a display area. A reflecting mirror is provided immediately above the element and on the front side of the counter substrate, and light emitting elements are provided on both ends of one side of the outer side of the display area where the light receiving element is not provided on the front side of the counter substrate. LCD device with position detection function. 2. The liquid crystal display device with a position detecting function according to claim 1, wherein light emitting wavelengths of the light emitting elements provided at both ends are different from each other. 3. A liquid crystal display device in which liquid crystal is sealed between a thin film transistor array substrate and a counter substrate, wherein a light receiving element is provided on the thin film transistor array substrate along four sides of an outer periphery of a display area. A reflection mirror is provided directly above the counter substrate and on the front side of the counter substrate, and a light emitting element is provided at two opposing corners of the outer periphery of the display area on the front side of the counter substrate, wherein a liquid crystal display with a position detection function is provided. apparatus. 4. The liquid crystal display device with a position detecting function according to claim 1, wherein the light receiving element is turned on and off by a liquid crystal shutter. 5. The liquid crystal display device with a position detecting function according to claim 1, wherein a light emitting diode is used as said light emitting element. 6. The liquid crystal display device with a position detecting function according to claim 1, wherein the light emitting element is turned on intermittently. 7. The light guide according to claim 1, wherein a light guide having a structure in which only a component parallel to the screen is output from the light exit of the light emitting element is provided. LCD device with position detection function. 8. The light guide according to claim 1, wherein a light guide having a structure in which light is incident only in a specific direction is provided above the light receiving element. A liquid crystal display device with the position detection function described in the above. 9. The reflecting mirror is arranged at an angle of 45 ° with respect to the screen so that a light component parallel to the screen is reflected in a direction perpendicular to the screen.
The angle of claim 1, 2, 3,
4. A liquid crystal display device with a position detection function according to 4, 5, 6, 7 or 8. 10. The method according to claim 1, wherein an amorphous silicon film is used as the light receiving element.
A liquid crystal display device with a position detection function according to 5, 6, 7, 8 or 9. 11. The structure according to claim 1, wherein said light receiving element is directly connected to a polycrystalline silicon thin film transistor.
A liquid crystal display device with the position detection function described in the above. 12. An anti-reflection process is applied to a portion outside the display area and where the reflecting mirror is not provided. 8,
A liquid crystal display device with a position detecting function according to 9, 10 or 11.