JPH07287246A - Projection type display device - Google Patents

Abstract

PURPOSE:To reduce a light leak in an active element and obtain an excellent image by shielding the active element from light by a light shield layer provided to an active matrix type liquid crystal panel. CONSTITUTION:Liquid crystal 14 is charged between a quartz glass substrate 11 on which a polarization plate 10 is stuck and a glass substrate 12 on which a polarization plate 13 is stuck. On the quartz glass substrate 11, a pixel electrode 18, a thin film transistor 17, a gate electrode wiring part 15, and a source electrode wiring part 16 are formed and on the glass substrate 12, the light shield layer 19 which is printed or dyed and a common electrode 20 are formed. The light shield layer 19 is formed overlapping with the pixel electrode 18 as much as or more than the thickness of the liquid crystal 14 to eliminate the influence of light which is made incident obliquely on the liquid crystal panel, cut off irradiation light 21 which is made incident from the side of the glass substrate 12, and prevent a leak current from increasing owing to the irradiation of the thin film transistor 17 with light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type display device using a liquid crystal panel.

[0002]

2. Description of the Related Art In a conventional projection display device, a cathode ray tube is enlarged and projected by a projection lens.

A projection type display device using a liquid crystal panel has also been tried, but it has not yet been put to practical use.

[0004]

However, the above-mentioned conventional technique has a problem that it is difficult to reduce the size and weight of the apparatus in the case of projecting a cathode ray tube. Of course, the cathode ray tube may be made small, but the small cathode ray tube has a problem that the display capacity is reduced.

A projection type display device using a liquid crystal panel has also been tried, but since it is an optical writing system and a thermal writing system, it takes time to form one screen, and moving images cannot be displayed. Have.

Therefore, the present invention provides a projection type display device using an active matrix type liquid crystal panel in which thin film transistors are integrated in order to solve such a problem. It is intended to provide a projection display device using a liquid crystal panel with a good image quality by reducing the leak current because it has a problem that it increases and deteriorates the surface quality.

[0007]

According to the present invention, a planar electrode and a thin film transistor are formed on a glass substrate on which a common electrode is formed in a projection type display device for color display using an active matrix type liquid crystal panel in which a thin film transistor is integrated. A light-shielding layer is formed in the gap between the planar electrodes of the glass substrate and a portion of the thin film transistor, and light for illuminating the liquid crystal panel is incident from the glass substrate side on which the common electrode and the light-shielding layer are formed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the structure of a liquid crystal panel.
FIG. 2 is a diagram showing an equivalent circuit of the liquid crystal panel.

In the figure, reference numeral 10 is a polarizing plate, which is attached to a quartz glass substrate 11 and 13 is attached to a glass substrate 12. Quartz glass substrate l1
A liquid crystal 14 is sealed between the glass substrate 12 and the glass substrate 12.

The quartz glass substrate 11 has a pixel electrode 18 made of an ITO film, a thin film transistor 17 and a gate line 1.
5, the source line 16 is formed. On the glass substrate 12, a light shielding layer 19 formed by printing or dyeing and a common electronic mark 20 made of an ITO film are formed.

The gate electrode wiring 15 is 15-1, 15-2.
... 15-N are sequentially selected in order and the thin film transistor 17 connected to the selected gate electrode 15 is made conductive.

Two thin film transistors 17 in FIG. 2 are used in series to reduce the leak current, but one may be used.

The source electrode wiring 16 includes 1611 and 1612.
.. .. 16N in the order shown, and is applied to the pixel electrode 18 through the thin film transistor 17 which is in the conductive state by being applied with the analog electric quantity corresponding to the image signal. Pixel electrode 1
Reference numeral 8 forms a capacitance with the common electrode 20 and liquid crystal, and the liquid crystal 14 is controlled by the amount of electricity stored in this capacitance to display an image.

Light-shielding layer 19 formed on glass substrate 12
Is configured to block the irradiation light 21 entering from the glass substrate 12 side. The light-shielding layer 19 is usually formed for the purpose of shielding light leaking from portions other than the pixels and improving the display contrast. However, in the present embodiment, in addition to the above-mentioned purpose, the thin film transistor is irradiated with light, so that the leakage current is reduced. Is formed for the purpose of preventing the increase of The light shielding layer 19 is formed so as to overlap the pixel electrode 18 with a thickness equal to or greater than the thickness of the liquid crystal 14. This is also to eliminate the influence of light obliquely incident on the liquid crystal panel.

FIG. 3 is a diagram showing the structure of the panel substrate. The panel substrate 30 is fixed with a liquid crystal panel and a driver IC for driving the liquid crystal panel to facilitate the interface with an external circuit and facilitate the handling of the liquid crystal panel. To do.

The panel board 30 has a connection terminal 31 for inputting a control signal from an external circuit, and a signal input to the connection terminal 31 is transmitted to an X driver board 32 and a Y driver board 34 by wiring formed on the panel board 30. The X driver IC 33 and the Y driver IC are connected by the connecting portion.
35 is driven. The X driver IC 33 is connected to the source electrode wiring 16 of the liquid crystal panel, outputs a signal corresponding to an image signal, and the Y driver IC selects and drives a row for displaying.

Reference numeral 38 indicates an X-side selection direction, and the X driver I
In C33, the source electrode wiring 16 of the display pixel portion 37 is sequentially selected from left to right for display. Reference numeral 39 denotes a Y-side selection direction, and the Y driver IC 33 selects and drives the gate electrode wiring 15 of the display pixel portion 37 from top to bottom.

FIG. 4 is a diagram showing the principle of color display,
This is an example in which three panel substrates 30 described in FIG. 3 are used and dichroic mirrors are arranged in a cross for color combination.

In the figure, the three panel substrates 30 are arranged so that the optical distances from the projection lens 42 are equal, and the busyness of the three panel substrates is red, green and blue which are the three primary colors of the additive color mixture. An image corresponding to each color of is displayed.

The image of the panel substrate 30 illuminated by the red light 43 is reflected by the red reflection mirror 40 and reaches the projection lens 42, and the surface image of the panel substrate 30 illuminated by the blue light 45 is reflected by the blue reflection mirror 41. It is reflected and reaches the projection lens 42. The panel substrate 30 illuminated by the green light 44 is a red reflection mirror 40.
And the blue reflection mirror 41 to reach the projection lens 42, and as a result, the images of the three panel substrates displaying the three primary colors are combined by reflecting or transmitting the dichroic mirror, and the projection lens 42 Is projected by.

However, in FIG. 4, since the three panel substrates 30 described in FIG. 3 are used, the X side selection direction 3
8 are optically aligned, the light incident surface is green from the RSU substrate 12 side, and red and blue are from the Sekisui glass substrate 11 side, and the thin film transistor 17 of the liquid crystal panel for displaying red and blue is provided. There is a problem that the light is irradiated on the film and the leak current increases.

Therefore, FIG. 5 is a view in which the directions of light incident on the liquid crystal panel are the same, and the light incident on the three panel substrates is always incident on the glass substrate 12 side on which the light shielding layer 19 is formed. It is arranged.

In order to achieve this object, the X-side selection direction 38 described in FIG. 3 may be reversed like the X-side selection direction (38) shown by the dotted line. This is accomplished by using an X driver IC 33 that can reverse the selection direction or by mounting the X driver board 32 in the left-right direction.

FIG. 6 is a top view showing the internal structure of the embodiment, and FIG. 7 is a side view showing the internal structure.

In the present embodiment, as shown in FIGS. 4 and 5, the method of arranging the dichroic mirrors in order is shown instead of the method of forming the dichroic mirrors in a cross shape.

In the figure, reference numeral 60 is a light source composed of a halogen lamp, a metal halide rasop, and a foul plate, and the light emitted from the light source 60 is composed of a lens 61, a heat ray cut filter 162, a reflection plate 63 and a lens 64. It is condensed by the illumination optical system to obtain almost parallel light. In the light emitted from the illumination optical system, blue light illuminates the blue display panel 71 by the blue reflection mirrors 65 and 68, and red light illuminates the red display panel 72 by the red reflection mirror 66. The marginal color light transmitted through the blue reflection mirror 65 and the red reflection mirror 66 illuminates the green display panel 73.

The composition of the images displayed on each display panel is as follows.
The image of the blue display panel 71 is transmitted through the red reflection mirror 69 and the green reflection mirror 70, the image of the red display panel 72 is reflected by the red reflection mirror 69, is transmitted through the green reflection mirror 70, and the display of the green display panel 73 is edged. The reflection mirrors 67 and 70 are reflected to reach the projection lens 42 and are projected.

Reference numeral 74 is a heat radiation fan that sucks out heat generated from the light source to the outside. Reference numeral 75 denotes a leg, which adjusts the height and angle of the layers. Reference numeral 76 denotes a circuit unit, which houses a power supply circuit and a control circuit. 77 is a cabinet.

6 and 7, if the panel substrate shown in FIG. 3 is used, the red display panel 72 is
Since the incident light is incident from the quartz substrate 11 side,
A glass substrate 1 having a light-shielding film formed by the method described in FIG.
The method of incidence is from the 2 side.

FIG. 8 is an external view of the projection display device.
7 is a cabinet, and 81 is a handle, which is used when moving. Reference numeral 82 is an operation unit including a control knob and an input terminal.

[0032]

As described above, according to the invention, by irradiating light from the side of the glass substrate on which the light shielding layer is formed,
Since light leakage of the thin film transistor can be reduced, the operation of the thin film transistor is stable and a good image can be obtained.

Further, by forming the light-shielding layer at the same time in the gap between the pixel electrodes other than the thin-film rumor transistor,
It is possible to improve the image contrast by blocking excess light.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a liquid crystal panel.

FIG. 2 is an equivalent circuit diagram of a liquid crystal panel.

FIG. 3 is a configuration diagram of a panel substrate.

FIG. 4 is a principle diagram of color display.

FIG. 5 is a principle diagram in which the directions of light entering the liquid crystal panel are the same.

FIG. 6 is a top view showing an internal configuration.

FIG. 7 is a side view showing an internal configuration.

FIG. 8 is an external view of a projection display device.

[Explanation of symbols]

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[Procedure amendment]

[Submission date] January 19, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

In the [0006] However the prior art described above, in which the projection cathode-ray tubes have between problem point that it is difficult size and weight of the device. Of course, the cathode ray tube may be made small, but the small cathode ray tube has a problem that the display capacity is reduced.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0005

[Correction method] Change

[Correction content]

A projection type display device using a liquid crystal panel has also been tried, but since it is an optical writing system and a thermal writing system, it takes time to form one screen, and moving images cannot be displayed. Have.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006] Therefore although the present invention is to provide a projection display device using an active matrix type liquid crystal panel in order to solve or these problems, the image quality leakage current increases when morphism irradiation light to the active element It is intended to provide a projection type display device using a liquid crystal panel having a good image quality by reducing the leak current because it has a problem of lowering.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

A projection display device of the present invention
Is an illuminating means for generating colored light of three colors, and
Each of the generated color lights is modulated according to the image signal.
Liquid crystal panel and each color modulated by each liquid crystal panel
Color combining means for color combining light and
Projection optical means for projecting the combined light thus combined,
Note: Multiple liquid crystal panels undergo an odd number of reflections after being modulated.
First tie for modulating color light guided to the projection optical means
LCD panel and if it is not reflected once after being modulated
Is a color light that is guided to the projection optical means after being reflected an even number of times.
Projection type table consisting of a second type liquid crystal panel for modulating light
In the device shown, the liquid crystal panel is
Active matrix having connected pixel electrodes in pixels
A liquid crystal panel, comprising the active element and the
Light-shielding layer that shields the color light entering through the gap between the pixel electrodes
To the pixel electrode through the active element.
A driver for selectively supplying the image signal is provided.
The liquid crystal panel of the first type is the same as the liquid crystal panel of the second type.
The liquid crystal panel is selectively supplied from the driver
It is characterized in that the supply order of the image signals is reversed .

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

A pixel electrode 18 made of an ITO film, a thin film transistor 17, and a gate electrode are arranged on the quartz glass substrate 11.
The line 15 and the source electrode wiring 16 are formed. A light shielding layer 19 formed by printing or dyeing and a common electrode 20 formed of an ITO film are formed on the glass substrate 12.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

The source electrode wiring 16 includes 1611 and 1612.
.. .. 16N in the order shown, and is applied to the pixel electrode 18 through the thin film transistor 17 which is in the conductive state by being applied with the analog electric quantity corresponding to the image signal. Pixel electrode 1
Reference numeral 8 forms a capacitance with the common electrode 20 and the liquid crystal, and the liquid crystal 14 is controlled by the amount of electricity stored in this capacitance to display an image.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

Light-shielding layer 19 formed on glass substrate 12
Are for the purpose of blocking the irradiation light 21 entering from the glass substrate 12 side. The light-shielding layer 19 is usually formed for the purpose of shielding light leaking from portions other than the pixels and improving the display contrast. However, in the present embodiment, in addition to the above-mentioned purpose, the thin film transistor is irradiated with light, so that the leakage current is reduced. Is formed for the purpose of preventing the increase of The light shielding layer 19 is formed so as to overlap the pixel electrode 18 with a thickness equal to or greater than the thickness of the liquid crystal 14. This is also for eliminating the influence of light incident on the liquid crystal panel obliquely.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

However, in FIG. 4, since the three panel substrates 30 described in FIG. 3 are used, the X side selection direction 3
When 8 are optically aligned, the light incident surface is green from the glass substrate 12 side, and red and blue are from the quartz glass substrate 11 side, and the thin film transistor 17 of the liquid crystal panel for displaying red and blue is There is a problem that light is irradiated and leak current increases.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Name of item to be corrected] 0032

[Correction method] Change

[Correction content]

[0032]

According to the invention as described above, according to the present invention, Akti
By the light-shielding layer provided on the live matrix type liquid crystal panel
Shields the active element to prevent light leakage from the active element
Therefore, the operation of the active element is stable and a good image can be obtained.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0033

[Correction method] Change

[Correction content]

At the same time, the light-shielding layer is also provided in the gap between the pixel electrodes.
By forming it, it is possible to improve the contrast of an image by shielding excess light.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomio Sonehara 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation (72) Inventor Shuji Ariga 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson Incorporated (72) Inventor Akitaka Yajima 3-3-5 Yamato, Suwa-shi, Nagano Seiko Epson Corporation

Claims (1)

[Claims] 1. A projection display device for performing color display using an active matrix type liquid crystal panel in which thin film transistors are integrated, wherein a pixel electrode is formed on a glass substrate on which a common electrode is formed and a pixel electrode on a glass substrate on which a thin film transistor is formed. By forming a light-shielding layer in the gap and the thin film transistor portion, the light illuminating the liquid crystal panel is
A projection display device, characterized in that light enters from a glass substrate side on which a common electrode and a light shielding layer are formed.