JPH03153211A - liquid crystal display device - Google Patents

Abstract

PURPOSE:To display a full-color image with good color balance at all times by providing color sensors for red, green, and blue outside the display area of a liquid crystal display panel and providing a voltage control part which adjusts the voltages of display driving signals for red, green, and blue to a display driving circuit which drives the liquid crystal display panel. CONSTITUTION:The color sensors 17a - 17c for red, green, and blue are provided outside the display area 1a of the liquid crystal display panel 1 and the display driving circuit 30 which drives the liquid crystal display panel 1 is provided with the voltage control part 33 which adjusts the voltages of the display driving signals for red, green, and blue. Then the color sensors 17a - 17c detect how much color components of red, green, and blue of light from a light source lamp are intense to adjust the voltages of the display driving signals for red, green, and blue which are applied to the liquid crystal display lamp 1 from the display driving circuit 30 according to the light intensity values of the respec tive color components detected by the color sensors 17a - 17c, i. e. the spectral distribution characteristics of the light from the light source lamp. Consequently, even if the spectral characteristics of the light source lamp vary, the full-color image with good color balance is obtained at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid crystal display device that displays full-color images.

[Conventional technology]

A liquid crystal display device that displays full-color images, such as television images, uses a pair of transparent substrates that face each other with a liquid crystal layer in between. Transparent display electrodes (for TFT active matrix liquid crystal display elements, selectively driven by thin film transistors) are mounted on opposing surfaces of a pair of transparent substrates that face each other with a liquid crystal layer in between. A pixel electrode and a counter electrode (for a simple matrix liquid crystal display element, a striped scanning electrode and a signal electrode) are formed on one of the pair of substrates, and red, green, and It consists of a liquid crystal display panel provided with a blue display color filter, and a display drive circuit that drives this liquid crystal display panel.

This liquid crystal display device drives the display of the liquid crystal display panel by applying a driving voltage from the display drive circuit to each display electrode of the liquid crystal display panel, and also changes the transmitted light of each pixel display part of this product display panel to red and green. , colored by a display color filter of blue, red, and green.

A full-color image is displayed by a combination of blue display pixels, and the drive voltage applied from the display drive path to each display electrode of the liquid crystal display panel is divided into red, green, and It depending on the wavelength dissimilarity of the liquid crystal display panel. In order to display a full-color image with good color balance by compensating for the difference in the transmittance of each wavelength of light, red, The voltage values are set so that the intensity of transmitted light of each wavelength of green and blue reaches a desired value.

[Problem to be solved by the invention]

However, in conventional liquid crystal display devices, the drive voltage value applied from the display drive circuit to each display electrode of the liquid crystal display panel is set at the manufacturing stage, so the spectral distribution of light from the light source lamp changes over time. When the color changes, the intensity of the red, green, and blue display destinations on the LCD panel changes accordingly, which often causes the full-color image displayed by the LCD panel to become an image with poor color balance. there was. This also applies when the light source lamp is replaced; if a lamp with spectral distribution characteristics different from that of the dedicated lamp is used as the light source lamp, the displayed image on the LCD panel may have poor color balance due to the characteristics of the light source lamp. turn into.

The present invention was made in view of the above-mentioned circumstances, and its purpose is to provide a liquid crystal display that can always display a full-color image with good color balance even if the spectral distribution characteristics of the light source lamp change. The purpose of this invention is to provide a display device.

[Means for solving the three problems] In order to achieve the above objects, the liquid crystal display device of the present invention has the following features:
Outside the display area of the liquid crystal display panel, a color filter with the same characteristics as the display color filter provided in the display area of the liquid crystal display panel and a photodetector element that detects the intensity of light passing through each color filter are provided. In addition, color sensors for red, green, and blue are provided, and a display drive circuit that drives this liquid crystal display panel is provided with color sensors for red, green, and blue that are applied to the liquid crystal display panel according to the light intensity detected by each of the color sensors. A voltage control unit is provided to adjust the voltage of the display drive signal to J1.

In the liquid crystal display device of the present invention, the display color filter provided in the display area of the liquid crystal display panel is formed on the light incident side substrate of a pair of transparent substrates facing each other with the liquid crystal layer in between. It is desirable that the color filter of the color sensor be formed on the light-incidence side substrate, and the photodetection element of the color sensor be formed on the light-emission side substrate.

Further, the present invention can be applied to a liquid crystal display device using a TFT active matrix type liquid crystal display panel and a liquid crystal display device using a simple matrix type liquid crystal display panel; In this case, as described above, the display color filter provided in the display area and the color filter of the color sensor are formed on the light-incidence side substrate, and the pixel electrode provided in the display area and the thin film transistor that selectively drives this pixel electrode are connected to the light-emitting device. A light detection element of a color sensor formed on the light emitting side substrate is formed on a side substrate, and a semiconductor layer made of the same material as the semiconductor layer of the thin film transistor, and an input/output electrode made of the same material as the source and drain electrodes of the thin film transistor. It is desirable to form a thin film element in which these are laminated.

[Effect]

In the liquid crystal display device of the present invention, color sensors for red, green, and blue are provided outside the display area of the liquid crystal display panel, and color sensors for red, green, and blue are provided in a display drive circuit that drives the liquid crystal display panel.
By providing a voltage control section that adjusts the voltage of the blue display drive signal, the intensity of each of the red, green, and blue color components of the light from the light source lamp is detected by the color sensor; Red and green are applied from the display drive circuit to the liquid crystal display panel according to the intensity of each color of light, that is, the spectral distribution characteristics of the light from the light source lamp.

The voltage of the blue display drive signal is adjusted, and the color filters of each color sensor have the same characteristics as the display color filter, so the intensity of light detected by each color sensor is This corresponds to the intensity of each color of light that is colored by the display color filter in the display area of the LCD panel, so it is applied to the LCD panel according to the intensity of red, green, and blue light detected by each color sensor. Red to do.

By adjusting the voltages of the green and blue display drive signals, a full-color image with good color balance can always be displayed even if the spectral distribution characteristics of the light source lamp change.

Further, in the liquid crystal display device of the present invention, the display color filter provided in the display area of the liquid crystal display panel may be
A liquid crystal layer is formed on a light incident side substrate of a pair of transparent substrates facing each other, a color filter of the color sensor is formed on the light incident side substrate, and a photodetecting element of the color sensor is formed on the light incident side substrate. If formed on the light emitting side substrate, the light detection element of the color sensor will detect the light that has passed through the color filter and the liquid crystal layer, and therefore will detect the light that has passed through the color filter and the liquid crystal layer in the display area. Light intensity can be detected under the same conditions as in Moreover, if the display color filter provided in the display area and the color filter of the color sensor are formed on the same substrate (light incident side substrate) as described above, the display color filter and the color sensor color filter can be formed on the same substrate (light incident side substrate). Since the above color filters can be formed at the same time, the liquid crystal display panel can be manufactured in one package.

Furthermore, when the present invention is applied to a liquid crystal display device using a TFT active matrix type liquid crystal display panel,
A display color filter provided in a display area of a product display panel and a color filter of a color sensor are formed on a light incident side substrate, a pixel electrode provided in the display area, a thin film transistor selectively driving the pixel electrode, and light detection of the color sensor. A thin film element in which a semiconductor layer made of the same material as the semiconductor layer of the thin film transistor and input/output electrodes made of the same material as the source and drain electrodes of the thin film transistor are laminated. Then, when manufacturing the liquid crystal display panel, not only the display color filter and the color filter of the color sensor can be formed at the same time, but also the thin film transistor and the photodetection element of the color sensor can be formed at the same time.
Therefore, the liquid crystal display panel can be manufactured more easily.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings regarding a liquid crystal display device using a TFT active matrix type liquid crystal display panel.

FIG. 1 shows the configuration of the liquid crystal display device of this embodiment. In the figure, 1 is a TFT active matrix type liquid crystal display panel, and this liquid crystal display panel 1 has a structure as shown in FIG. ing.

That is, in FIG. 2, reference numerals 2.3 denote a pair of transparent substrates made of glass, and the upper substrate 2 in the figure is a light-incidence side substrate, and the lower substrate 3 is a light-emission side substrate. The pair of substrates 2 and 3 are bonded together via a frame-shaped sealing material 4 along the outer periphery thereof, and a liquid crystal 5 is sealed between the side substrates 2 and 3.

Transparent pixel electrodes 6 and thin film transistors 7 for selectively driving the pixel electrodes 6 are arranged vertically and horizontally on the surface of the light-emitting side substrate 3 facing the liquid crystal layer over the entire display area 1a of the liquid crystal display panel 1. has been done. This thin film transistor 7 is of an inverted staggered type, and includes a gate electrode 8 formed on the surface of the light emitting side substrate 3 and a transparent gate insulating film formed on almost the entire surface of the light emitting side substrate 3 covering the gate electrode 8. Then, an l-type semiconductor layer 10 is formed on this gate insulating film 9 to face the gate electrode 8, and this l-type semiconductor layer 10 is
A source electrode 12 and a drain electrode 13 are formed on both sides of a type semiconductor layer 10 with an n type semiconductor layer 11 interposed therebetween.

The gate electrode 8 is connected to a gate line (not shown) wired on the surface of the light-emitting substrate 3, and the drain electrode 13 is connected to a data line (not shown) wired on the gate insulating film 9 so as to be perpendicular to the gate line. connected to. Further, the pixel electrode 6 is connected to the gate insulator 89.
This pixel electrode 6 is connected to the source electrode 12 of the thin film transistor 7.

Further, on the surface of the light-incidence side substrate 2 facing the liquid crystal layer, display color filters of three colors of red, green, and blue are arranged alternately, facing each pixel electrode 6 formed on the light-emission side substrate 3. It is formed by Note that FIG. 2 shows only the outermost row of pixel display sections in the display area 1a, and the color filter of this pixel display section is, for example, a red filter 14R.

Further, on the color filter forming surface of the light incident side substrate 2, a transparent counter electrode 15 facing each of the pixel electrodes 6 is provided.
is formed.

Moreover, in FIG. 2, 17a and 17b.

17c is a color sensor for red, green, and blue provided outside the display area 1a of the liquid crystal display panel 1, and these color sensors 17a, 17b.

17c are color filters 18R and 18G formed on the surface of the light incident side substrate 2 facing the liquid crystal layer, respectively.

18B, and photodetecting elements 19a, 19b, and 19c formed on the surface of the light-emitting side substrate 3 facing the liquid crystal layer to face the color filters 18R, 18G, and 18B.

Among the color filters 18R, 18G, and 18B of the color sensors 17a, 17b, and 17c, the color filter 18R of the red color sensor 17a is the red display color filter 14R provided in the red pixel display section of the display area 1a. The color filter 18G of the green color sensor 17b has the same characteristics as the green display color filter (not shown) provided in the green pixel display section of the display area 1a. and the color filter 1 of the blue color sensor 17c
A color filter 8B has the same characteristics as a blue display color filter (not shown) provided in the blue pixel display section of the display area 1a. In addition, in this example,
The color filters 18R, 18G, and 18B are made of the same material as the red, green, and blue display color filters, respectively.

Also, each of the color sensors 17a and 17b.

17c photodetection elements 19 a, 19 b r 19
c are all thin film elements, and each of the photodetecting elements 19a, 19b, 19c is connected to the light emitting side substrate 3.
On the gate insulating film 9, which is formed over almost the entire surface of the surface, an I! 2 semiconductor layer 20 is formed, and this l
Input/output connections made of the same material as the source and drain electrodes 12 and 13 of the thin film transistor 7 are provided on both sides of the type semiconductor layer 20 via an n-type semiconductor layer 21 made of the same material as the n-type semiconductor layer 11 of the thin film transistor 7. It has a structure in which electrodes 22 and 23 are formed. Note that the input/output electrode 22.2
3, the input side electrode 22 is connected to an input line (not shown),
Further, the output side electrode 23 is connected to an output line (not shown). These input lines and output lines are wired on the gate insulating film 9, and their ends are connected to the light output side substrate 3.
It is led out to the side edge of.

Although not shown, an alignment film is formed on the electrode formation surfaces of the side substrates 2 and 3 from the display area 1a to the color sensor formation area, and aligns the liquid crystal 5 sealed between the side substrates 2 and 3. The molecules are arranged in a twisted manner between the side substrates 2.3. In the figure, 24 is a light shielding film formed on the outer surface of the light incident side substrate 2 to face the thin film transistor 7, and 25.26 is a polarized light film provided on the outer surface of the display area 1a of the side substrates 2 and 3. The direction of the polarization axis of the polarizing plate 26 on the light output side is such that when a display drive voltage is applied between the pixel electrode 6 and the counter electrode 15 (when the liquid crystal molecules are aligned in a rising direction), the polarization axis direction is set such that the polarization axis direction of the polarizing plate 26 on the light output side is such that when the display drive voltage is applied between the pixel electrode 6 and the counter electrode 15 (when the liquid crystal molecules are aligned in a rising direction) When no voltage is applied (when liquid crystal molecules are in a twisted arrangement)
is aligned in the h direction to block light transmitted through the liquid crystal layer.

On the other hand, in FIG. 1, reference numeral 30 denotes a display drive circuit for driving the liquid crystal display panel 1, and this display drive circuit 30 has gates that sequentially apply a scanning signal (gate voltage) to each gate line of the liquid crystal display panel 1. It consists of a drive circuit 31 and a drain drive circuit 32 that applies red, green, and blue display drive signals (drain voltages) R, G, and B to each data line of the liquid crystal display panel 1. Further, a voltage control section 33 is provided on the output side of the drain drive circuit 32,
Each color sensor 17a, 17 provided on the liquid crystal display panel 1
b, photodetection element 19a of 17c.

The output lines connected to the input/output electrodes 22 and 23 of 19b and 19c are connected to the voltage control section 33, respectively. This voltage control section 33 controls the photodetection elements 19a, 19b of each of the color sensors 17a, 17b, 17c.
, red detected by 19c.

Drain drive circuit 32 depending on the light intensity of each color of green and blue.
The red signal applied to each data line of the liquid crystal display panel 1 from
Each color sensor 17a adjusts the voltage of display drive signals R, G, and B for green and FT.

Photodetection elements 19a and 19b of 17b and 17c.

The light intensities of each color of red, green, and blue that are manually inputted from 19c are compared, and the voltages of the display drive signals R, G, and B for red, green, and blue are changed according to the difference in the light intensity of each color.

That is, for example, the spectral distribution characteristic of the light from the light source lamp is such that the light intensity of short wavelengths (blue component) is strong, and among the light intensities of each color detected by each color sensor 17a, 17b, and 17c, the intensity of blue light is If the voltage is strong, the voltage control section 33
is the display drive signal R for each color from the drain drive circuit 32
. To compensate for the display image on a panel 1 to be bluish. This also applies when the light intensity of other colors is strong.

That is, the liquid crystal display device has color sensors 17 for red, green, and blue outside the display area 1a of the liquid crystal display panel 1.
a, 17b, and 17c, and a voltage control section 33 that adjusts the voltages of the red, green, and blue display drive signals R, G, and B in the display drive circuit 30 that drives the liquid crystal display panel 1, The color sensor 17a measures the intensity of each color component of red and green W from the light source lamp.

17b and 17c, each color sensor 17a,
Display drive signals R, G of red, green, and ft are applied from the display drive circuit 30 to the liquid crystal display panel 1 according to the intensity of the light of each color detected by 17b and 17c, that is, the spectral distribution characteristics of the light from the light source lamp. .

The voltage of B is adjusted by 33. In this case, each of the color sensors 17a and 17b.

Since the color filters 18R, 18G, and 18B of 17c have the same characteristics as the display color filters (red filter 14R, green filter, and blue filter), each color sensor 17a, 17b.

The intensity of light detected by 17c corresponds to the intensity of light of each color colored by the display color filter in display area 1a of product display panel 1, respectively. Therefore, as mentioned above, each color sensor 17a.

Red and green are applied to the liquid crystal display panel 1 according to the intensities of red, green and blue light detected by 17b and 17C.

By adjusting the voltages of the blue display drive signals R, G, and B, a full-color image with good color balance can always be displayed even if the spectral distribution characteristics of the light source lamp change.

Further, in the above embodiment, the display area 1 of the liquid crystal display panel 1
The display color filter provided in a is formed on the light-incidence side substrate 2 of a pair of transparent substrates 2 and 3 facing each other with a liquid crystal layer in between, and the color filters 17a and 17b
, 17c color filters 18R, 18G, 18B are formed on the light incident side substrate 2, and the color sensors 17a,
17b.

Photodetection elements 19a, 19b*19 of 17c
Since C is formed on the light emitting side substrate 3, the photodetecting elements 19a of the color sensors 17a, 17b, and 17c.

19b and 19c are color filters 18R118G, 1
The light passing through 8B and the liquid crystal layer is detected. Therefore, the photodetecting element 19a.

19b and IQc, it is different from detecting the light transmitted through the color filter and liquid crystal layer of the display area 1a (the transmitted light before entering the light output side polarizing plate 26 in a state where no display drive voltage is applied). It is possible to detect the light intensity under different conditions. Moreover, as described above, the display color filter and color sensors 17a, 17b provided in the display area 1a,
If the color filters 18R, 18G, and 18B of 17c are formed on the same substrate (light incident side substrate) 2 and both color filters are made of the same material, when manufacturing the liquid crystal display panel 1, it is possible to Color filter and color sensor 17a, 17b.

Since the color filters 18R, 18G, and 18B of 17c can be formed at the same time, the liquid crystal display panel 1 can be manufactured in a compact manner.

Furthermore, as in the above embodiment, a display color filter and a color sensor 1 provided in the display area 1a of the liquid crystal display panel 1 are provided.
7a, 17b, 17c color filters 18R, 18G
, 18B are formed on the light incident side substrate 2, and the display area 1
A pixel electrode 6 provided at a, a thin film transistor 7 for selectively driving the pixel electrode 6, and color sensors 17a and 17b.
.

The photodetecting elements 19a, 19b, and 19c of 17c are formed on the light emitting side substrate 2, and the photodetecting elements 19a,
19b and 19c are an i-type soil conductor layer 20 and an n-type semiconductor layer 21 made of the same materials as the i-type conductor layer 10 and n-type semiconductor layer 11 of the thin film transistor 7, and the source of the thin film transistor 7.

Input/output electrode 22. made of the same material as drain electrode 12.13.
23, when manufacturing the liquid crystal display panel 1, the display color filter and the color filters 18R, 18R of the color sensors 17a, 17b, 17c,
18G and 18B at the same time, the thin film transistor 7 and the color sensors 17a, 17b, 1
The photodetecting elements 19a, 19b, and 19c of 7c can also be formed at the same time, so that the liquid crystal display panel 1 can be manufactured more easily.

In the above embodiment, the counter electrode 15 formed on the incident side substrate 2 of the liquid crystal display panel 1 is formed on the display color filter (the red filter 14R, the green filter, and the blue filter). 15 may be formed under the display color filter (and the light shielding film 24 may be provided on the surface of the incident side substrate 2 facing the liquid crystal layer or on the thin film transistor 7. In addition, in the above embodiment, the TFT active Although a liquid crystal display device using a matrix type liquid crystal display panel has been described, the present invention can of course be applied to a liquid crystal display device using a simple matrix type liquid crystal display panel.

〔Effect of the invention〕

In the liquid crystal display device of the present invention, color sensors for red, green, and V private use are provided outside the display area of the liquid crystal display panel, and red, green, and
By providing a voltage control section that adjusts the voltage of the blue display drive signal, the intensity of each of the red, green, and blue color components of the light from the light source lamp is detected by the color sensor; Red and green are applied from the display drive circuit to the liquid crystal display panel according to the intensity of each color of light, that is, the spectral distribution characteristics of the light from the light source lamp.

Since the voltage of the blue display drive signal is adjusted, a full-color image with good color balance can always be displayed even if the spectral distribution characteristics of the light source lamp change.

Further, in the liquid crystal display device of the present invention, the display color filter provided in the display area of the liquid crystal display panel may be
The color filter of the color sensor is formed on the light incidence side substrate of a pair of transparent substrates facing each other with a liquid crystal layer in between, and the light detection element of the color sensor is formed on the light incidence side substrate. If it is formed on the output side substrate, the light intensity can be detected under the same conditions as when detecting light transmitted through the color filter and liquid crystal layer in the display area. If the color filter for display and the color filter for the color sensor are formed on the same substrate (light incident side substrate), the color filter for display and the color filter for the color sensor can be formed at the same time when manufacturing the above-mentioned liquid crystal display panel. It is possible to manufacture liquid crystal display panels in small quantities.

Furthermore, when the present invention is applied to a liquid crystal display device using a TFT active matrix type product display panel,
A display color filter provided in a display area of a liquid crystal display panel and a color filter of a color sensor are formed on a light incident side substrate, a pixel electrode provided in the display area, a thin film transistor for selectively driving the pixel electrode, and light detection of the color sensor. A thin film element in which a semiconductor layer made of the same material as the semiconductor layer of the thin film transistor and input/output electrodes made of the same material as the source and drain electrodes of the thin film transistor are laminated. Then, when manufacturing the liquid crystal display panel, not only the display color filter and the color filter of the color sensor can be formed at the same time, but also the thin film transistor and the photodetection element of the color sensor can be formed at the same time.
Therefore, the liquid crystal display panel described above can be manufactured more compactly.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the present invention, in which FIG. 1 is a configuration diagram of a liquid crystal display device, and FIG. 2 is a sectional view of a color sensor forming portion of a liquid crystal display panel. 1...Liquid crystal display panel, 1a...Display area, 2...
・Incidence side substrate, 3... Output side substrate, 5... Liquid crystal, 6
... Pixel electrode, 7... Thin film transistor, 8...
Gate electrode, 9... Gate insulating film, 10... I-type semiconductor layer, 11... N-type semiconductor layer, 12... Source electrode, 13... Drain electrode, 14R... Color for display Filter (red filter) 15-... counter electrode,
17a, 17b. 17c...Color sensor, 18R, 18G, 18B.
... Color filter, 19a, 19b, 19c... Photodetection element, 20... I-type semiconductor layer, 21... N-type semiconductor layer, 22.23... Input/output electrode, 24... Light shielding Film, 25.26... Polarizing plate, 30... Display drive circuit, 31... Gate drive circuit, 32... Drain drive circuit, 33... Voltage control section.

Claims (3)

[Claims] (1) In a liquid crystal display device comprising a liquid crystal display panel that is equipped with red, green, and blue color filters to display a full-color image, and a display drive circuit that drives this liquid crystal display panel, the liquid crystal display panel a color filter having the same characteristics as the display color filter outside the display area;
A color sensor for red, green, and blue consisting of a light detection element that detects the intensity of light that has passed through each color filter is provided, and the display drive circuit is provided with a color sensor that detects the intensity of light that has passed through each color filter. A liquid crystal display element comprising a voltage control section that adjusts voltages of red, green, and blue display drive signals applied to the liquid crystal display panel. (2) The display color filter provided in the display area of the liquid crystal display panel is formed on the light-incidence side substrate of a pair of transparent substrates facing each other with the liquid crystal layer in between, and the color filter of the color sensor is formed on the light incident side substrate. 2. The liquid crystal display device according to claim 1, wherein the light detecting element of the color sensor is formed on the light-incidence side substrate, and the light-detecting element of the color sensor is formed on the light-emission side substrate. (3) The liquid crystal display panel is a TFT active matrix type liquid crystal display panel, and a pixel electrode provided in the display area and a thin film transistor for selectively driving this pixel electrode are formed on a light-emitting side substrate. The photodetecting element of the color sensor formed in 1 is made of a thin film element in which a semiconductor layer made of the same material as the semiconductor layer of the thin film transistor and input/output electrodes made of the same material as the source and drain electrodes of the thin film transistor are laminated. The liquid crystal display device according to claim 2, characterized in that: