JP2008158273A - Electrooptical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrooptical device capable of controlling luminance of a display part in accordance with brightness of external environment, that a human feels. <P>SOLUTION: The electrooptical device is provided with: liquid crystal E filled into a gap between an element substrate 11 and a counter substrate 70; a PIN diode 31 which is formed on the element substrate 11 and detects the brightness of external environment; and a control part which controls the luminance of a backlight on the basis of a photoelectric current signal from the PIN diode 31. A wavelength selection filter 50 made of a dielectric multilayer film which is set so as to emit external light L2 to the PIN diode 31 while enhancing green light is disposed on the incident course of external light L2 with respect the PIN diode 31 and on the side nearer to display surface side than the PIN diode. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electro-optical device.

2. Description of the Related Art Conventionally, electro-optical devices such as liquid crystal display devices and organic EL display devices have characteristics such as thinness and high definition, and are widely used in various fields. In particular, from the viewpoint of thinning, applications to electronic devices such as display screens for mobile phones, display displays for televisions, advertising displays, etc. are spreading.

In such an electro-optical device, the luminance of the display unit is set to be sufficiently high so that the screen can be clearly seen even when the external environment is bright (the external light illuminance is high). However, when the luminance of the display unit is set in this way, even when the external environment is dark (the external light illuminance is low), the luminance of the display unit remains high with respect to the external environment, which can reduce power consumption. There is a problem that you can not. In particular, in the case of a portable electronic device such as a cellular phone, it is an important problem to reduce power consumption.

Therefore, in order to realize low power consumption, a method of automatically adjusting the luminance of the display unit according to the brightness of the external environment has been proposed (for example, see Patent Document 1). That is, Patent Document 1
The liquid crystal display device includes a light receiving element that detects the brightness of the external environment, and adjusts the luminance of the backlight according to the brightness of the external environment detected by the light receiving element. The organic EL display device also includes a light receiving element similar to that of Patent Document 1, and the maximum value of the data signal supplied to each organic EL element is determined according to the brightness of the external environment detected by the light receiving element. It can be considered to automatically adjust the luminance of the display unit by adjusting.
Japanese Patent Laid-Open No. 9-146073

However, the light receiving element of Patent Document 1 is generally formed of single crystal silicon,
The spectral sensitivity characteristic of this light receiving element is significantly different from the visual sensitivity felt by human eyes.
That is, the spectral sensitivity of this type of light receiving element extends in the infrared light region, and is significantly different from the visibility characteristic having a peak sensitivity near 555 nm. Therefore, when this type of light-receiving element is used, the brightness of the display unit cannot be accurately adjusted according to the brightness of the external environment that is perceived by humans, resulting in sufficiently low power consumption. There is a problem that you can not.

The present invention has been made to solve the above problems, and an object thereof is to provide an electro-optical device capable of adjusting the luminance of a display unit in accordance with the brightness of the external environment felt by humans. It is in.

The electro-optical device of the present invention is based on a display element formed on an element substrate, a light receiving element that is formed on the element substrate and detects the brightness of an external environment, and a detection result by the light receiving element.
In the electro-optical device including the control unit that adjusts the luminance of the display element, the green light is on the incident path of the incident light with respect to the light receiving element and closer to the incident surface side of the incident light than the light receiving element. A wavelength selective filter made of a dielectric multilayer film having a transmittance set so as to emit the incident light to the light receiving element is emphasized.

According to the electro-optical device of the present invention, the wavelength selection filter includes the green light (50
(Light having a wavelength in the range of 0 nm to 560 nm) is emphasized, that is, the green light of the incident light is transmitted more than the light of the other colors and emitted to the light receiving element. Accordingly, the spectral sensitivity characteristic of the light receiving element that receives incident light through this wavelength selection filter is a characteristic that approximates the human visual sensitivity characteristic having a peak sensitivity of about 555 nm and high sensitivity to green light. Thereby, the brightness of the display element can be adjusted according to the brightness of the external environment that humans feel. As a result, low power consumption of the electro-optical device can be sufficiently realized. Further, since the light receiving element is formed on the element substrate on which the display element is formed, the cost can be reduced as compared with the case where an external light receiving element is provided. That is, according to the above configuration, there is no need for a step of independently manufacturing a light receiving element and a step of coupling the light receiving element and the electro-optical device, which are necessary when an external light receiving element is provided. The number of manufacturing steps and cost can be reduced.

The electro-optical device includes a plurality of pixel circuits formed in a matrix on the element substrate and configured to include switching elements, and at least a part of the dielectric film of the wavelength selection filter is included in each pixel circuit. You may make it serve as a gate insulating film.

According to this electro-optical device, since at least a part of the dielectric film of the wavelength selection filter is also used as a gate insulating film that has been conventionally provided, an increase in size of the device due to the formation of the wavelength selection filter is suppressed. be able to.

In this electro-optical device, the lowermost dielectric film of the wavelength selection filter may also serve as the lowermost layer of the gate insulating film.
According to this electro-optical device, a larger number of dielectric films can also be used as a conventionally provided gate insulating film.

The electro-optical device includes a plurality of pixel circuits formed in a matrix on the element substrate and configured to include switching elements, and at least a part of the dielectric film of the wavelength selection filter is included in each pixel circuit. You may make it also serve as the interlayer insulation film formed in the upper surface of each gate electrode.

According to this electro-optical device, since at least a part of the dielectric film of the wavelength selection filter is also used as an interlayer insulating film that has been conventionally provided, an increase in the size of the device due to the formation of the wavelength selection filter is suppressed. be able to. In particular, when the lowermost dielectric film of the wavelength selection filter also serves as the lowermost layer of the gate electrode, almost all dielectric films of the wavelength selection filter are used as the conventional gate insulating film and interlayer insulating film. It can also be used. Thereby, the enlargement of the apparatus by formation of a wavelength selection filter can be suppressed more suitably.

According to this electro-optical device, the switching element is a polysilicon TFT (Thin Fil
The light receiving element may be formed of a photodiode or phototransistor made of polysilicon.

According to this electro-optical device, since the switching element and the light receiving element can be manufactured in the same process, an increase in the number of manufacturing processes can be suppressed.
According to this electro-optical device, the dielectric multilayer film constituting the wavelength selection filter includes a low refractive index layer made of a low refractive index dielectric and a refractive index higher than the refractive index of the low refractive index layer. High refractive index layers made of a dielectric may be alternately stacked.

According to this electro-optical device, green light of the incident light is emphasized and emitted to the light receiving element by the dielectric multilayer film in which the low refractive index layers and the high refractive index layers are alternately stacked.
According to this electro-optical device, the low refractive index layer may be made of a silicon oxide film, and the high refractive index layer may be made of a silicon nitride film.

Usually, a gate insulating film and an interlayer insulating film such as a switching element are formed of a silicon oxide film or a silicon nitride film. Therefore, according to this electro-optical device, since the wavelength selection filter is formed by the same material and manufacturing method as those of the conventional gate insulating film and interlayer insulating film, a new material for forming the wavelength selective filter is provided. In addition, the wavelength selection filter can be easily formed without the need for a manufacturing apparatus or the like.

(First embodiment)
A first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is a block diagram illustrating a circuit configuration of a liquid crystal display device as an electro-optical device, and FIG. 2 is a cross-sectional view of main parts of a pixel circuit and a photosensor in a display unit.

As shown in FIG. 1, a rectangular display portion 12 enclosing liquid crystal molecules is formed on one side surface (element formation surface 11 a) of the element substrate 11 of the liquid crystal display device 10. The display unit 12 includes
A pixel region 13 in which pixel circuits P including a thin film transistor (TFT) 20 as a switching element are arranged in a matrix is provided. That is, each pixel circuit P in the pixel region 13 includes a plurality of scanning lines S extending in the row direction (lateral direction in FIG. 1) and the column direction (
1 are respectively arranged at intersections with a plurality of data lines D extending in the vertical direction in FIG. Each scanning line S and each data line D are connected to a scanning line driving circuit 14 and a data line driving circuit 15 formed outside the display unit 12, respectively. A plurality of photosensors 30 are formed outside the pixel region 13 in the display unit 12. These optical sensors 3
0 detects the brightness of the external environment. Specifically, each optical sensor 30 receives external light and outputs a photocurrent signal based on the external light to the control unit 16. A wavelength selection filter 50 (see FIG. 2), which will be described later, is provided on the upper surface of each optical sensor 30. In the present embodiment, each photosensor 30 is composed of a PIN diode 31 (see FIG. 2).

The control unit 16 controls the scanning line driving circuit 14 and the data line driving circuit 15 in an integrated manner. That is, the control unit 16 generates various signals to be sent to the scanning line driving circuit 14 and the data line driving circuit 15 based on display data input from an external device (not shown).

Based on the photocurrent signal supplied from the photosensor 30, the control unit 16 performs the element substrate 11.
The amount of light (luminance) of the planar light L1 of the backlight 17 provided on the lower surface of the backlight 17 is adjusted. Control unit 1
6 adjusts the brightness of the planar light L1 of the backlight 17 based on a table value in which the correlation between the photocurrent signal from the optical sensor 30 and the brightness of the planar light L1 of the backlight 17 is set in advance, for example. More specifically, when the photocurrent signal from the photosensor 30 is large (the external environment is bright), the control unit 16 increases the brightness of the planar light L1 of the backlight 17 and the photocurrent from the photosensor 30. When the signal is small (the external environment is dark), the brightness of the planar light L1 of the backlight 17 is lowered.

The scanning line driving circuit 14 generates a scanning signal based on the signal from the control unit 16, and the data line driving circuit 15 generates a data signal based on the signal from the control unit 16. The liquid crystal display device 10 controls the alignment state of liquid crystal molecules for each pixel circuit P in the display unit 12 based on the scanning signal of the scanning line driving circuit 14 and the data signal of the data line driving circuit 15. Yes.
Then, the liquid crystal display device 10 displays the desired image on the display unit 12 by modulating the plane light L1 from the backlight 17 provided on the lower surface of the element substrate 11 according to the alignment state of the liquid crystal molecules. ing. At this time, the brightness of the planar light L1 of the backlight 17 is adjusted by the control unit 16 according to the brightness of the external environment.

The display unit 12, the scanning line driving circuit 14, the data line driving circuit 15, and the control unit 16 of the liquid crystal display device 10 described above are configured by independent electronic components (for example, a one-chip semiconductor integrated circuit device). Also good. Further, the display unit 12, the scanning line driving circuit 14, the data line driving circuit 15, and the control unit 16 may be configured as an electronic component in which all or part of them are integrated. For example, the scanning line driving circuit 14 and the data line driving circuit 15 may be integrally formed on the display unit 12. Display unit 12, scanning line driving circuit 14, data line driving circuit 15
All or a part of the control unit 16 may be configured by a programmable IC chip, and the function may be realized by software by a program written in the IC chip.

Next, the structure of the TFT 20 and the photosensor 30 constituting the pixel circuit P will be described with reference to FIG.
As shown in FIG. 2, the display unit 12 on the element formation surface 11 a of the element substrate 11 has a light shielding film 41 for blocking the incidence of the planar light L <b> 1 from the backlight 17 to the TFT 20, and the light sensor from the backlight 17. A light shielding film 42 for blocking the incidence of the planar light L1 on the light 30 is formed. An insulating film 43 made of a silicon oxide film (SiO ₂ ) or the like deposited so as to cover substantially the entire display portion 12 of the element formation surface 11a is formed above the light shielding films 41 and.

A semiconductor layer 22 made of polysilicon constituting a switching element is formed on the upper surface of the insulating film 43 and above the light shielding film 41. The semiconductor layer 22 includes a P-type channel region 22c formed at the center thereof, and has an N-type source region 22s and a drain region 22d on both sides of the channel region 22c.

A PIN diode 31 as an optical sensor 30 is formed on the upper surface of the insulating film 43 and above the light shielding film 42. The PIN diode 31 is formed at the center position of I
An I-type region 32i made of type polysilicon is provided, and an N-type region 32n and a P-type region 32p made of polysilicon are provided on both sides of the I-type region 32i.

On the upper side of the semiconductor layer 22 and the PIN diode 31, a gate insulating film 46 made of a silicon oxide film or the like is formed so as to cover substantially the entire display portion 12 of the element formation surface 11a. A gate electrode 24 extending from the scanning line S is formed on the upper surface of the gate insulating film 46 and above the channel region 22 c of the semiconductor layer 22. The source region 22
The s and drain regions 22d are formed in a self-aligned manner by ion implantation of phosphorus ions using the gate electrode 24 as a mask. The gate electrode 24, the source region 22s, and the drain region 22d form a TFT 20 as a switching element.

A via hole BH penetrating the gate insulating film 46 is formed on the I-type region 32 i of the PIN diode 31. A wavelength selection filter 50 is formed in the via hole BH, that is, on the I-type region 32 i of the PIN diode 31. This wavelength selection filter 50
Is external light L as incident light incident from the outside of the liquid crystal display device 10 (upper side in FIG. 2).
2 is emphasized with green light (light having a wavelength in the range of 500 nm to 560 nm) and then emitted to the PIN diode 31 formed below the wavelength selection filter 50. Specifically, as shown in FIG. 3, the wavelength selection filter 50 has a high transmittance with respect to light having a wavelength in the range of 500 nm to 620 nm, and particularly very light with respect to light having a wavelength in the range of 530 nm to 580 nm. It has a high transmittance, and has a transmittance characteristic that transmits approximately 100% of light having a wavelength of about 555 nm. Accordingly, the spectral sensitivity characteristic of the PIN diode 31 to which the external light L2 that has passed through the wavelength selection filter 50 is incident is a characteristic that approximates the human visual sensitivity characteristic that has a peak sensitivity near about 555 nm and high sensitivity to green light. It becomes.

The structure of the wavelength selection filter 50 will be described in detail below.
As shown in FIG. 2, a silicon nitride film (on the upper side of the I-type region 32i, the gate electrode 24, and the gate insulating film 46 of the PIN diode 31 is deposited so as to cover substantially the entire display portion 12 of the element formation surface 11a. A first dielectric film 51 made of SiN is formed. The first dielectric film 51 is formed so as to have a thickness of about 75 nm. A second dielectric film 52 made of a silicon oxide film is formed on substantially the entire upper surface of the first dielectric film 51. The second dielectric film 52 is formed so as to have a thickness of about 90 nm.

A third dielectric film 53 made of a silicon nitride film is formed on substantially the entire upper surface of the second dielectric film 52. The third dielectric film 53 is formed so as to have a thickness of about 75 nm. A fourth dielectric film 54 made of a silicon oxide film is formed on substantially the entire upper surface of the third dielectric film 53. The fourth dielectric film 54 is formed so as to have a thickness of about 90 nm.

A fifth dielectric film 55 made of a silicon nitride film is formed on substantially the entire upper surface of the fourth dielectric film 54. The fifth dielectric film 55 is formed to have a thickness of about 75 nm. A sixth dielectric film 56 made of a silicon oxide film is formed on substantially the entire upper surface of the fifth dielectric film 55. The sixth dielectric film 56 is formed so as to have a thickness of about 90 nm.

As described above, the wavelength selection filter 50 includes a high refractive index layer (a dielectric layer having a relatively high refractive index).
(Silicon nitride film) and a dielectric multilayer film in which low refractive index layers (silicon oxide films) made of a dielectric having a refractive index lower than that of the silicon nitride film are alternately stacked. The transmittance characteristic of the wavelength selection filter 50 shown in FIG. 3 is adjusted by the thickness and refractive index of each dielectric film constituting the wavelength selection filter 50. That is, in this embodiment, the transmittance characteristic of the wavelength selection filter 50 is the maximum transmittance (for example, 100% transmittance) with respect to light having a wavelength of about 555 nm.
And having a high transmittance for green light (for example, a transmittance of 90% or more)
The material and film thickness of each dielectric film are set. By setting the transmittance characteristic of the wavelength selection filter 50 in this way, the spectral sensitivity characteristic of the PIN diode 31 can be approximated to the human visual sensitivity characteristic.

The first dielectric film 51 to the sixth dielectric film 56 function as the wavelength selection filter 50 on the PIN diode 31, and function as the first interlayer insulating film 61 in the display unit 12 including the TFT 20. That is, the first interlayer insulating film 61 in the display unit 12 includes the wavelength selection filter 50 (first dielectric film 51 to sixth dielectric film 56).

On the source region 22 s of the semiconductor layer 22, a contact hole H <b> 1 penetrating the first dielectric film 51 to the sixth dielectric film 56 as the gate insulating film 46 and the first interlayer insulating film 61 is formed. In the contact hole H1, the data line D electrically connected to the source region 22s by a conductive film made of aluminum or the like is formed. On the other hand, the semiconductor layer 2
On the second drain region 22d, a first insulating film 46 and a first interlayer insulating film 61 are formed.
A contact hole H2 penetrating through the dielectric film 51 to the sixth dielectric film 56 is formed. In the contact hole H2, the drain region 2 is formed by a conductive film made of aluminum or the like.
A drain electrode 62 electrically connected to 2d is formed.

On the N-type region 32n of the PIN diode 31, the gate insulating film 46 and the first dielectric film 5
A contact hole H3 penetrating the first to sixth dielectric films 56 is formed. A first electrode 63 electrically connected to the N-type region 32n is formed in the contact hole H3 by a conductive film made of aluminum or the like. On the other hand, the P-type region 32 of the PIN diode 31.
On the p, a contact hole H4 penetrating the gate insulating film 46 and the first dielectric film 51 to the sixth dielectric film 56 is formed. A second electrode 64 electrically connected to the P-type region 32p by a conductive film made of aluminum or the like is formed in the contact hole H4. The PIN diode 31 is connected to the control unit 16 (see FIG. 1) via the first electrode 63 and the second electrode 64. The PIN diode 31 receives external light L2 that is incident through the wavelength selection filter 50, and outputs a photocurrent signal based on the external light L2 to the control unit 16. At this time, since the spectral sensitivity characteristic approximates to the human visual sensitivity characteristic as described above, the PIN diode 31 outputs a photocurrent signal corresponding to the brightness of the external environment felt by the human to the control unit 16. The control unit 16 adjusts the brightness of the planar light L <b> 1 of the backlight 17 based on the photocurrent signal from the PIN diode 31. Therefore, the brightness of the planar light L1 of the backlight 17 can be adjusted by the wavelength selection filter 50, the PIN diode 31, and the control unit 16 in accordance with the brightness of the external environment felt by humans.

A second interlayer insulating film 65 made of a silicon oxide film or the like is formed on the data line D, the drain electrode 62, and the first and second electrodes 63 and 64 so as to cover the first interlayer insulating film 61. .

On the drain electrode 62, a contact hole H5 penetrating the second interlayer insulating film 65 is formed. In the contact hole H5, a pixel electrode 66 electrically connected to the drain electrode 62 by a transparent conductive film made of ITO or the like is formed for each pixel circuit P.

The lower surface of the counter substrate 70 that is bonded to the element substrate 11 so as to face the element substrate 11.
At a position facing the TFT 20 formed above, a black matrix BM made of a light-shielding material that blocks external light L2 incident on the TFT 20 from the upper surface (display surface) of the counter substrate 70 is formed. . On both sides of the black matrix BM, color filters CF that transmit only light of a specific wavelength (for example, red light, green light, blue light, etc.) are formed. By this color filter CF, only light of a specific wavelength out of the light L1 of the backlight 17 is emitted to the display surface as display light.

Under the black matrix BM and the color filter CF, an organic flattening film 71 made of acrylic resin or the like is formed so as to cover almost the entire surface of the counter substrate 70. Organic planarization film 71
A counter electrode 72 made of a light-transmitting conductive material such as ITO (Indium-Tin-Oxide)
However, as a common electrode for the pixel electrode 66, it is formed over the entire surface of the counter substrate 70 without being partitioned for each pixel circuit P. The counter electrode 72 is electrically connected to a power supply circuit (not shown), and a predetermined voltage is supplied from the power supply circuit.

The element substrate 11 and the counter substrate 70 are arranged so that the pixel electrode 66 and the counter electrode 72 face each other, and the liquid crystal E is sealed between the pixel electrode 66 and the counter electrode 72. .

According to this embodiment described above, the following effects can be obtained.
(1) According to the present embodiment, the upper part of the PIN diode 31, more specifically, on the incident path of the external light L2 with respect to the PIN diode 31, and closer to the display surface than the PIN diode 31,
A wavelength selection filter 50 is provided. The wavelength selection filter 50 is composed of a dielectric multilayer film in which low refractive index layers and high refractive index layers are alternately stacked, and is set to have a high transmittance with respect to green light. As a result, the external light L2 that has passed through the wavelength selection filter 50 is incident P
The spectral sensitivity characteristic of the IN diode 31 can be approximated to the human visual sensitivity characteristic. Then, the control unit 16 adjusts the luminance of the planar light L1 of the backlight 17 based on the photocurrent signal from the PIN diode 31. Therefore, the brightness of the planar light L1 of the backlight 17 can be adjusted by the wavelength selection filter 50, the PIN diode 31, and the control unit 16 in accordance with the brightness of the external environment felt by humans. As a result, low power consumption of the liquid crystal display device 10 can be sufficiently realized.

(2) According to the present embodiment, the first dielectric film 51 to the sixth dielectric film 56 of the wavelength selection filter 50 are also used as the first interlayer insulating film 61 in the display unit 12. This first interlayer insulating film 6
Since 1 is normally formed even in a liquid crystal display device in which the wavelength selection filter 50 is not formed, the enlargement of the liquid crystal display device 10 due to the formation of the wavelength selection filter 50 can be suitably suppressed.

Further, since the first interlayer insulating film 61 is formed by the wavelength selection filter 50, the light L1 from the backlight 17 is emphasized by the first interlayer insulating film 61 (wavelength selection filter 50). Is incident on the color filter CF. Usually, in a display device that displays a color image using the color filter CF, RG is used to match the human visual sensitivity characteristic.
Of the three primary color filters of B, the number (area) of green (G) color filters is larger (larger) than other red (R) and blue (B) color filters. On the other hand, in the case of the liquid crystal display device 10 of the present embodiment, since the light with the enhanced green light is incident on the color filter CF, even if the RGB color filters are formed uniformly, the color image Can be suitably displayed.

(3) According to this embodiment, the low refractive index layer of the wavelength selection filter 50 is formed from a silicon oxide film, and the high refractive index layer is formed from a silicon nitride film. These silicon oxide films and silicon nitride films are materials that are often used as gate insulating films and interlayer insulating films in conventional liquid crystal display devices. Therefore, the wavelength selection filter 50 can be easily formed by a conventionally used material or manufacturing method. Further, since the wavelength selection filter 50 is formed from such a silicon oxide film and silicon nitride film, the wavelength selection filter 50 is also provided in the liquid crystal display device including the polysilicon TFT 20 that requires high temperature processing as in this embodiment. Can be applied.

(4) According to this embodiment, the polysilicon TFT 20 as the switching element and the PIN diode 31 made of polysilicon as the light receiving element are formed on the element substrate 11. Thereby, since the TFT 20 and the PIN diode 31 can be simultaneously formed by the same process, an increase in the number of manufacturing steps can be suppressed.

Further, since the switching element and the light receiving element are provided on the same substrate, the cost can be reduced as compared with the case where an external light receiving element is provided.
(Second Embodiment)
A second embodiment embodying the present invention will be described below with reference to FIGS. Figure 1 above
The same members as those shown in FIG. 3 are denoted by the same reference numerals, and detailed description of these components is omitted.

As shown in FIG. 4, a wavelength selection filter 80 is formed on the PIN diode 31. The wavelength selection filter 80 emphasizes the green light and emits the external light L2 to the PIN diode 31 formed below the wavelength selection filter 80. Specifically, as shown in FIG. 5, the wavelength selection filter 80 has a high transmittance with respect to light having a wavelength in the range of 510 nm to 590 nm, and particularly very light with respect to light having a wavelength in the range of 530 nm to 560 nm. It has a high transmittance and has a transmittance characteristic that gives a maximum transmittance for light having a wavelength of about 550 nm. Accordingly, the spectral sensitivity characteristic of the PIN diode 31 to which the external light L2 that has passed through the wavelength selection filter 80 is incident is a characteristic that approximates the human visual sensitivity characteristic that is highly sensitive to green light.

The structure of the wavelength selection filter 80 will be described in detail below.
A first dielectric film 81 made of a silicon oxide film is formed on the semiconductor layer 22 and the PIN diode 31 so as to cover substantially the entire display portion 12 of the element formation surface 11a. The first dielectric film 81 is formed so as to have a thickness of about 80 nm. A second dielectric film 82 made of a silicon nitride film is formed on substantially the entire upper surface of the first dielectric film 81. The second dielectric film 82 is formed to have a thickness of 150 nm.

A gate electrode 24 extending from the scanning line S is formed on the upper surface of the second dielectric film 82 and above the channel region 22 c of the semiconductor layer 22. Thus, the first dielectric film 81 and the second dielectric film 82 function as the wavelength selection filter 80 on the PIN diode 31 and function as the gate insulating film 46 in the display unit 12 including the TFT 20. That is, the gate insulating film 46 is composed of the first dielectric film 81 and the second dielectric film 82.

Above the second dielectric film 82 and the gate electrode 24, a third dielectric film 83 made of a silicon oxide film deposited so as to cover substantially the entire element formation surface 11a is formed. The third dielectric film 83 is formed so as to have a film thickness of 80 nm. A fourth dielectric film 84 made of a silicon nitride film is formed on substantially the entire upper surface of the third dielectric film 83. The fourth dielectric film 84 is formed so as to have a thickness of 80 nm. A fifth dielectric film 85 made of a silicon oxide film is formed on substantially the entire upper surface of the fourth dielectric film 84. The fifth dielectric film 85 is formed so as to have a thickness of 20 nm.

As described above, similarly to the first embodiment, the wavelength selection filter 80 includes the first dielectric film 81 to the fifth dielectric film.
A low refractive index layer (silicon oxide film) composed of a dielectric film 85 and made of a dielectric having a relatively low refractive index (low refractive index), and a dielectric having a refractive index higher than the refractive index of the silicon oxide film It consists of a dielectric multilayer film in which high refractive index layers made of are alternately laminated. The transmittance characteristic of the wavelength selection filter 80 shown in FIG. 5 is adjusted by the thickness and refractive index of each dielectric film constituting the wavelength selection filter 80. That is, in the present embodiment, the transmittance characteristics of the wavelength selection filter 80 are such that each dielectric has a maximum transmittance with respect to light having a wavelength of about 550 nm and a high transmittance with respect to green light. The material and film thickness of the film are set.

The third dielectric film 83 to the fifth dielectric film 85 function as the wavelength selection filter 80 on the PIN diode 31, and function as the first interlayer insulating film 61 in the display unit 12 including the TFT 20.

As described above, according to the embodiment described above, the following effects are obtained in addition to the effects (1) to (4) of the first embodiment.
(5) According to the present embodiment, the first dielectric film 81 (lowermost dielectric film) of the wavelength selection filter 80 is used as the lowermost layer of the gate insulating film 46 in the display unit 12, and the second
The dielectric film 82 is also used as all the remaining gate insulating films 46 in the display unit 12. Since the gate insulating film 46 is normally formed even in a liquid crystal display device in which the wavelength selection filter 80 is not formed, the liquid crystal display device 1 by forming the wavelength selection filter 80.
The increase in size of 0 can be suitably suppressed. Further, the third dielectric film 83 to the fifth dielectric film 85 which are all the remaining dielectric films of the wavelength selection filter 80 are also used as the first interlayer insulating film 61 in the display unit 12. Thereby, the enlargement of the liquid crystal display device 10 by forming the wavelength selection filter 80 can be suppressed more suitably.

Further, the lowermost dielectric film (first dielectric film 81) of the wavelength selection filter 80 is also used as the lowermost layer of the gate insulating film 46. Therefore, the wavelength selection filter 80 as in the first embodiment.
In addition to the step of forming the gate insulating film 46, the gate insulating film 4 on the PIN diode 31 is formed.
The step of etching 6 can be omitted, and an increase in the number of manufacturing steps can be suppressed.

(6) The first dielectric film 81 that functions as the lowermost layer of the wavelength selection filter 80 and the gate insulating film 46 is formed of a silicon oxide film. That is, the semiconductor layer 22 made of polysilicon.
The layer in contact with the upper surface of the PIN diode 31 is formed of a silicon oxide film having stable insulation. Thereby, high electrical and physical stability can be maintained.

(Other embodiments)
In addition, the said embodiment can also be implemented in the following aspects which changed this suitably.
In each of the above embodiments, the optical sensor 30 as the light receiving element is configured by the PIN diode 31, but the optical sensor 30 may be configured by a phototransistor and a PN diode, for example.

For example, the phototransistor 90 as the optical sensor 30 may be formed as shown in FIG. Specifically, the gate electrode 91 is formed on the insulating film 43, and the gate insulating film 46 is formed above the gate electrode 91. A semiconductor layer 92 made of polysilicon is formed on the upper surface of the gate insulating film 46. The semiconductor layer 92 includes a P-type channel region 92c formed at the center thereof, and N-type source regions 2 on both sides of the channel region 92c.
2s and a drain region 22d. These gate electrode 91 and semiconductor layer 92 constitute a phototransistor 90. On the upper surface of the semiconductor layer 92, for example, a second
By forming the wavelength selection filter 80 in the embodiment, substantially the same effect as in the first and second embodiments can be obtained. Note that when the phototransistor 90 illustrated in FIG. 6 is used as a light receiving element, the TFT 20 is preferably formed to have a structure similar to that of the phototransistor 90.

In the first embodiment, all of the first dielectric film 51 to the sixth dielectric film 56 constituting the wavelength selection filter 50 are also used as the first interlayer insulating film 61. For example, as shown in FIG. As described above, at least one dielectric film (here, the first dielectric film 51) is formed on the gate insulating film 46.
You may make it share as a part of.

In each of the above embodiments, at least a part of the dielectric film of the wavelength selection filters 50 and 80 also serves as the first interlayer insulating film 61. For example, at least a part of the dielectric film of the wavelength selection filters 50 and 80 May also serve as the second interlayer insulating film 65.

In the first embodiment, all of the first dielectric film 51 to the sixth dielectric film 56 constituting the wavelength selection filter 50 are also used as the first interlayer insulating film 61. For example, the first dielectric film 1 to 5 dielectric films (for example, only the first dielectric film 51) among the films 51 to the sixth dielectric film 56
May also be used as the first interlayer insulating film 61.

In the second embodiment, the dielectric film of the wavelength selection filter 80 that is also used as the gate insulating film 46 is two layers. However, for example, the dielectric film that is also used as the gate insulating film 46 may be one layer. Three or more layers may be used.

In each of the above embodiments, the all dielectric film constituting the wavelength selection filters 50 and 80 is changed to PIN.
The diode 31 and the display unit 12 are formed over the entire upper surface. For example, at least a part of the dielectric film of the wavelength selection filters 50 and 80 is formed in the I-type region 3 of the PIN diode 31.
It may be formed only on 2i. In this case, it is necessary to form a dielectric film by masking a region other than the I-type region 32i of the PIN diode 31 with a photoresist or the like.

In the second embodiment, the first dielectric film 81, which is the lowermost layer of the wavelength selection filter 80, is formed of a silicon oxide film. For example, the first dielectric film 81 is formed of a silicon nitride film. May be.

If the wavelength selection filters 50 and 80 in each of the above embodiments are set to have a transmittance characteristic having a high transmittance with respect to green light, the number of dielectric films constituting the wavelength selection filters 50 and 80 The thickness and material of each dielectric film are not particularly limited.

The liquid crystal E above the photosensor 30 (PIN diode 31) in each of the above embodiments may be omitted. That is, the liquid crystal E may be sealed only in the pixel region 13 in the display unit 12.

-There is no restriction | limiting in particular in the number of the optical sensors 30 in each said embodiment. Further, the arrangement location of the optical sensor 30 is not particularly limited as long as it is on the element substrate 11. For example, the optical sensors 30 may be provided at the four corners of the display unit 12.

In each of the above embodiments, by adjusting the brightness of the planar light L1 of the backlight 17,
Although the brightness of the liquid crystal E as the display element is adjusted, the present invention is not limited to this. For example, the brightness of the liquid crystal E may be adjusted by adjusting the maximum value of the data signal supplied to each TFT 20.

In the above-described embodiment, the element substrate 11 is disposed on the backlight 17 side. However, the configuration is not limited thereto, and for example, the counter substrate 70 may be disposed on the backlight 17 side.
In each of the above embodiments, the liquid crystal display device 10 that can display a full-color image is embodied. However, for example, the liquid crystal display device may display only a monochrome image.

In each of the above embodiments, the liquid crystal E is embodied as the display element. However, the present invention is not limited to this, and for example, an organic EL element or an inorganic EL element may be used as the display element. That is, the wavelength selection filters 50 and 80 of each embodiment can be applied to, for example, an organic EL display device. In this case, it is preferable to adjust the luminance of the display element by adjusting the maximum value of the data signal supplied to the display element in accordance with the brightness of the external environment felt by humans.

By the way, as a method of approximating the spectral sensitivity characteristic of the light receiving element to the visual sensitivity characteristic, a method of forming a green color filter at a position facing the spectral element is conceivable. However, in the case of an organic EL display device, a color image may be displayed without using a color filter. In the case of such an organic EL display device, the method of approximating the visibility characteristic with a green color filter increases the size of the device by the amount of the green color filter. Furthermore, a new manufacturing apparatus for forming the color filter is required, which increases the manufacturing cost. On the other hand, in the case of the wavelength selective filters 50 and 80 of the above-described embodiments, since the gate insulating film and the interlayer insulating film that are conventionally provided are formed, the increase in size of the device can be suitably suppressed. . Furthermore, since the wavelength selective filters 50 and 80 can be formed by a conventional manufacturing method without requiring a new manufacturing apparatus, an increase in manufacturing cost can be suppressed.

In each of the above embodiments, the wavelength selection filters 50 and 80 are applied to the transmissive liquid crystal display device 10, but the wavelength selection filters 50 and 80 are applied to a reflective or transflective liquid crystal display device. It may be. In this case, the brightness of the liquid crystal E may be adjusted by adjusting the maximum value of the data signal supplied to each TFT 20 in accordance with the brightness of the external environment felt by humans.

In each of the embodiments described above, the TFT 20 is embodied as the switching element. However, the present invention is not limited to this.
The present invention may be applied to an active matrix liquid crystal display device using a device (thin film diode device).

In each of the above embodiments, the present invention is embodied in a so-called active matrix liquid crystal display device including the TFT 20 as a switching element, but may be applied to a passive matrix liquid crystal display device.

In each of the above embodiments, the TFT 20 and the PIN diode 31 are formed of polysilicon. However, for example, the TFT 20 and the PIN diode 31 may be formed of amorphous silicon.

1 is a block diagram showing a circuit configuration of a liquid crystal display device according to a first embodiment. Similarly, the principal part sectional drawing which shows a display part and an optical sensor. Similarly, the characteristic view which shows the transmittance | permeability characteristic of a wavelength selection filter. The principal part sectional drawing which shows the display part and optical sensor in 2nd Embodiment. Similarly, the characteristic view which shows the transmittance | permeability characteristic of a wavelength selection filter. Sectional drawing which shows the optical sensor in another example. The principal part sectional drawing which shows the display part and optical sensor in another example.

Explanation of symbols

E ... Liquid crystal as display element, P ... Pixel circuit, L2 ... External light as incident light, 10 ... Liquid crystal display device as electro-optical device, 11 ... Element substrate, 16 ... Controller, 20 ... Thin film transistor as switching element , 24... Gate electrode, 30... Optical sensor as a light receiving element, 31
... PIN diode as light receiving element, 46 ... gate insulating film, 61 ... first interlayer insulating film, 5
0, 80... Wavelength selection filter, 51 to 56, 81 to 85... Dielectric film constituting dielectric multilayer film, 90.

Claims (7)

A display element formed on the element substrate; a light receiving element formed on the element substrate for detecting brightness and darkness of an external environment; and a control unit for adjusting luminance of the display element based on a detection result by the light receiving element In an electro-optical device comprising:
On the incident path of incident light with respect to the light receiving element, the transmittance is such that the incident light is emitted to the light receiving element with green light being emphasized closer to the incident surface side of the incident light than the light receiving element. An electro-optical device, comprising a wavelength selection filter made of a dielectric multilayer film having a thickness of λ. A plurality of pixel circuits formed in a matrix on the element substrate and including switching elements;
The electro-optical device according to claim 1, wherein at least a part of the dielectric film of the wavelength selection filter also serves as a gate insulating film in each pixel circuit. 3. The electro-optical device according to claim 2, wherein the lowermost dielectric film of the wavelength selection filter also serves as the lowermost layer of the gate insulating film. A plurality of pixel circuits formed in a matrix on the element substrate and including switching elements;
4. The dielectric film according to claim 1, wherein at least a part of the dielectric film of the wavelength selection filter also serves as an interlayer insulating film formed on an upper surface of each gate electrode in each pixel circuit.
The electro-optical device according to one. 5. The switching element according to claim 2, wherein the switching element is made of a polysilicon TFT (Thin Film Transistor), and the light receiving element is made of a photodiode or a phototransistor made of polysilicon. The electro-optical device according to 1. The dielectric multilayer film constituting the wavelength selective filter is:
The low refractive index layer made of a dielectric material having a low refractive index and the high refractive index layer made of a dielectric material having a refractive index higher than the refractive index of the low refractive index layer are alternately laminated. Item 6. The electro-optical device according to any one of Items 1 to 5. 7. The electro-optical device according to claim 6, wherein the low refractive index layer is made of a silicon oxide film, and the high refractive index layer is made of a silicon nitride film.

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