JP2563774B2 - Projection display device - Google Patents

Description

The present invention relates to a projection display device using an active matrix liquid crystal panel.

[Conventional technology]

FIG. 4 shows a principle view of a projection type display device using a conventional active matrix type liquid crystal panel. In this figure, three liquid crystal panel substrates 30 (described later in the embodiment) are used, and dichroic mirrors 40 and 41 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 each of the three panel substrates has three colors of red, green, and blue which are the three primary colors of the additive color mixture. The image corresponding to is displayed.

The image of the panel substrate 30 illuminated by the red light 43 is reflected once by the red reflection mirror 40 and reaches the projection lens 42. Blue light 45
The image of the panel substrate 30 illuminated by is also reflected once by the blue reflection mirror 41 and reaches the projection lens 42. On the other hand, the image of the panel substrate 30 illuminated by the green light 44 passes through the red reflection mirror 40 and the blue reflection mirror 41 (that is, is not reflected even once) and reaches the projection lens 42. As a result, the images of the three panel substrates which are displayed in correspondence with the three primary colors are combined by reflecting or transmitting the dichroic mirrors 40 and 41, and projected by the projection lens 42.

Since red and blue are reflected once, when viewed from the light incident side of the panel substrate (liquid crystal light valve), the image scanning direction from left to right was reflected by the reflection mirror and projected. When it is guided by the lens, it flips right to left. Also, green is not reflected even once, so when viewed from the light incident side of the liquid crystal light valve, the scanning direction of the image is right → left, but even if guided by the projection lens, it is right → left. do not do.

[Problems to be Solved by the Invention]

The structure of an active matrix type liquid crystal panel as used in FIG. 4 is shown in FIG. 1, its equivalent circuit is shown in FIG.
The structure of the panel substrate is shown in FIG. 3 (details will be described later). In the active matrix type liquid crystal panel, as shown in FIGS. 1 and 2, a thin film transistor 17 serving as an active element is connected to each pixel electrode 18.

In the three liquid crystal panels 30 used in FIG. 4, when the X side selection direction 38 (see FIG. 3) is attempted to be optically aligned, the incident light is green from the glass substrate 12 side and red and blue from the glass substrate 12 side. Color synthesis cannot be performed unless from the quartz glass substrate 11 side.

As a result, the thin film transistor 17 of the liquid crystal panel for displaying red and blue is irradiated with light without passing through the light shielding layer,
There is a problem that the leak current increases and the image quality is degraded.

Therefore, in view of the above problems, the present invention provides a projection type display in which each liquid crystal light valve is arranged so as to provide a light shielding layer that shields a thin film transistor on a color light incident side of a liquid crystal panel, thereby improving image quality without increasing cost. To provide a device.

[Means for solving the problem]

In order to solve the above problems, the projection display device of the present invention has an illumination unit that generates a plurality of color lights, a plurality of liquid crystal panels that modulate each color light generated by the illumination unit based on an image signal, and A color synthesizing unit that color-synthesizes the respective color lights modulated by the liquid crystal panel, and a projection optical unit that projects the synthetic light that has been color-synthesized by the color synthesizing unit. A liquid crystal panel of a first type that modulates the color light guided to the projection optical means through an odd number of reflections, and the color light that is not reflected once after being modulated or is guided to the projection optical means after an even number of reflections. A liquid crystal panel of a second type for modulating light, wherein each liquid crystal panel has a liquid crystal sealed between a pair of substrates, and a matrix is formed on the inner surface of one of the substrates. A plurality of pixel electrodes arranged on the plurality of pixel electrodes, a plurality of signal lines to which the image signals are supplied, and a plurality of thin film transistors that supply the image signals supplied to the plurality of signal lines to the plurality of pixel electrodes. And a light-shielding layer that shields the plurality of thin film transistors from incident color lights, is formed on the inner surface of the other substrate, and each of the liquid crystal panels includes a plurality of signal lines for the plurality of signal lines. The image signals are sequentially allocated in the order of arrangement, and a driver configured to supply the allocated image signals is provided. In each of the liquid crystal panels, each color light is incident from the other substrate side, and from the one substrate side. The driver of the liquid crystal panel of the first type is configured to sequentially allocate the image signals to the plurality of signal lines arranged from one end side of the arrangement order, The driver of the second type liquid crystal panel is characterized in that the image signals are sequentially allocated to the plurality of signal lines arranged from the other end side in the arrangement order.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

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

In the figure, 10 is a polarizing plate, 11 is attached to a quartz glass substrate, and 13 polarizing plates are attached to 12 glass substrates. A liquid crystal 14 is sealed between the quartz glass substrate 11 and the glass substrate 12. Has been done.

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

The gate electrode wirings 15 are sequentially selected in the order shown by 15-1, 15-2, ... 15-N, and the thin film transistors 17 connected to the selected gate electrode wirings 15 are 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 is connected to the pixel electrode through the thin film transistor 17 to which the analog electric quantity corresponding to the image signal is applied in the order indicated by 16-1, 16-2, ...
Applied to 18. The pixel electrode 18 forms a capacitance by the common electrode 20 and the liquid crystal, and the liquid crystal is formed by the amount of electricity stored in this capacitance.
Controls 14 to display an image.

The light shielding layer 19 formed on the glass substrate 12 is the glass substrate 12
It is formed for the purpose of blocking the irradiation light 21 entering from the 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.
In the present embodiment, in addition to the above purpose, the thin film transistor is formed for the purpose of preventing an increase in leak current due to light irradiation. 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 to eliminate the influence of light incident on the liquid crystal panel in an oblique direction.

FIG. 3 is a view showing the configuration of the panel substrate. The panel substrate 30 fixes the liquid crystal panel and the driver IC for driving the liquid crystal panel, facilitates the interface with an external circuit, and facilitates the handling of the liquid crystal panel. It is a thing.

The panel board 30 has a connection terminal 31 for inputting a control signal from an external circuit, and the signal input to the connection terminal 31 is connected to the X driver board 32 and the Y driver board 34 by a connection formed by wiring formed on the panel board 30. And each X driver
It drives IC33 and Y driver IC35. X driver IC33
Is connected to the source electrode wiring 16 of the liquid crystal panel, outputs a signal corresponding to the image signal, and the Y driver IC selects and drives a row for displaying.

38 is an X side selection direction, and the X driver IC 33 sequentially selects the source electrode wiring 16 of the display pixel section 37 from left to right, allocates and supplies an image signal, and supplies the image signal for display on the display pixel section. 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 section 37 from top to bottom.

FIG. 4 is a diagram showing the principle of the color projection display device described above. 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. Is.

In the figure, the three panel substrates 30 are arranged so that the optical distances from the projection lens 42 are equal, and each of the three panel substrates 30 has a red / red color which is the three primary colors of the additive color mixture.
Images corresponding to each color of green and blue are 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 image of the panel substrate 30 illuminated by the blue light 45 is reflected by the blue reflection mirror 41 and projected. To the lens 42. The panel substrate 30 illuminated by the green light 44 passes through the 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 performing display corresponding to the three primary colors are: Synthesized by reflecting or transmitting a dichroic mirror,
The image is projected by the projection lens 42.

However, in FIG. 4, since the three panel substrates 30 described in FIG. 3 are used, if the X-side selection direction 38 is optically aligned, the surface on which the light enters is green on the glass substrate 12. From the side, red and blue come from the quartz glass substrate 11 side, and the thin film transistor 17 of the liquid crystal panel for displaying red and blue is irradiated with light, which causes a problem that leakage current increases.

Therefore, FIG. 5 is a diagram showing an embodiment 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 from the glass substrate 12 side on which the light shielding layer 19 is formed. It is arranged to do.

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. To do so, X driver IC33
Is achieved by using one that can reverse the selection direction or by mounting the X driver board 32 in the opposite direction. Therefore, in FIG. 5, in order to form a composite image guided to the lens 42, the red and blue liquid crystal panels form a reverse image with respect to the composite image, and the green liquid phase panel does not. To form.

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 this embodiment, as shown in FIG. 4 and FIG. 5, the dichroic mirror is not constructed by a cross,
The structure which arranges a dichroic mirror in order is shown.

In the figure, 60 is a light source composed of a halogen lamp or a metal halide lamp and a reflector, and a lens 61 emitted from the light source 60, a heat ray cut filter 62, a reflector 63 and
It is condensed by an illumination optical system composed of 64 to obtain almost parallel light. The light emitted from the illumination optical system is blue light illuminating the blue display panel 71 by the blue reflecting mirrors 65 and 68, and 66
The red reflection mirror illuminates the red display panel 72 with red light. The green light transmitted through the blue reflection mirror 65 and the red reflection mirror 66 illuminates the green display panel 73.

The images displayed on the respective display panels are synthesized such that the image on the blue display panel 71 passes through the red reflection mirror 69 and the green reflection mirror 70, and the image on the red display panel 72 reflects the red reflection mirror 69, and the green reflection mirror 69. 70 through the green display panel 73 and the green reflection mirrors 67 and 70 on the display to reflect the respective projection lenses.
It reaches 42 and is projected. Therefore, in FIG. 6, in order to form a composite image guided to the lens 42, the red panel 72 is formed.
Forms a reverse image with respect to the composite image, and the blue and green panels 71 and 73 form a non-reverse image.

74 is a heat dissipation fan, which handles the heat generated by the light source to the outside. 75 is a leg that adjusts the height and angle of the device. Reference numeral 76 denotes a circuit unit, which houses a power supply circuit and a control circuit. 77 is a cabinet.

Even in the configuration shown in FIGS. 6 and 7, if the panel substrate shown in FIG. 3 is used, the incident light will enter the red display panel 72 from the quartz substrate 11 side. By the method described above, the light is incident from the glass substrate 12 side on which the light shielding film is formed.

FIG. 8 is an external view of the projection type display device. Reference numeral 77 is a cabinet and 81 is a handle, which is used when moving. Reference numeral 82 is an operation unit having a control block or an input terminal.

〔The invention's effect〕

As described above, the present invention relates to a first type liquid crystal panel in which a plurality of liquid crystal panels that modulate a plurality of color lights are modulated and then the color lights that are guided to the projection optical unit after being reflected an odd number of times, A projection type display device comprising a second type liquid crystal panel which is not reflected once after being modulated, or which modulates color light guided to the projection optical means after being reflected an even number of times. The panel has, on the inner surface of one substrate, pixel electrodes arranged in a matrix, a plurality of signal lines to which image signals are supplied, and a plurality of thin film transistors for supplying image signals from the signal lines to the pixel electrodes. The inner surface of the other substrate is formed with a light-shielding layer that shields the thin film transistors from the incident light, and each liquid crystal panel is arranged so that color light is incident from one substrate side and emitted from the other substrate side. And it will be further first and second
By allocating the image signals to the signal lines of the signal line driver of the liquid crystal panel of the type in the reverse order, the following remarkable effects can be obtained.

a) By allocating the image signals by the driver of the liquid crystal panel of one type of the first and second type liquid crystal panels in the reverse direction to that of the driver of the liquid crystal panel of the other type, one panel Image is inverted with respect to the other panel, eliminating the need to flip one type of liquid crystal panel. Accordingly, any of the liquid crystal panels can be arranged so that the color light is incident from the other substrate on which the light shielding layer is formed and the color light is emitted from the one substrate. Therefore, the thin film transistor formed on the inner surface of the other substrate can reliably and accurately shield the thin film transistor on the inner surface of the one substrate, and the light leakage of the thin film transistor can be reliably reduced. As a result, the operation of the thin film transistor is stabilized, and the image quality of the image modulated by the liquid crystal panel, and thus the composite image, can be improved.

b) It is possible to prevent an increase in cost without preparing a light shielding layer as a separate component. In addition, all liquid crystal panels,
Since the color light can be incident from the other substrate on which the light-shielding layer is formed and the color light can be emitted from the one substrate, the structure of the inner surface of the substrate can be the same as that of each liquid crystal panel, and the inner structure of the different substrates can be different. There is no need to prepare two types of liquid crystal panels having the above, and it is possible to prevent an increase in cost.

c) Further, the structure of the inner surface of the substrate can be made the same as that of each liquid crystal panel, and the incident color light is not modulated by the two types of liquid crystal panels having different inner surface structures of the substrate, so that the optical characteristics of each liquid crystal panel are made uniform. This makes it possible to balance the light of each color in the composite image.

d) Since the driver has a simple configuration in which the image signal allocation in the driver for supplying the image signal to the signal line is reversed, a memory for storing the image signal for one screen is not necessary. That is, if the driver assignment is made the same for each liquid crystal panel, the image signal to be supplied to one type of liquid crystal panel is stored in advance in the memory as an image signal for one screen, and the image signal is converted into an inverted image. Must be read and supplied to the driver. However, according to the present invention, the image signal is directly supplied to the driver,
The memory and its control circuit are not needed because the signals are only assigned in reverse order in the driver. As a result, the structure is extremely simple, the number of parts is reduced, and the size and cost of the device can be reduced.

[Brief description of drawings]

FIG. 1 is a block diagram of a liquid crystal panel. FIG. 2 is an equivalent circuit diagram of the liquid crystal panel. FIG. 3 is a block diagram of a panel substrate. Fig. 4 is the principle of color display. FIG. 5 is a principle view in which the directions of light entering the liquid crystal panel are the same. FIG. 6 is a top view showing the internal structure. FIG. 7 is a side view showing the internal structure. FIG. 8 is an external view of the projection display device.

Front page continuation (72) Inventor Junichi Nakamura 3-5 Yamato, Suwa-shi Seiko Epson Corporation (72) Inventor Tomio Sonehara 3-3-5 Yamato Suwa-shi Seiko Epson Corporation (72) Inventor Shuji Ariga 3-3-5 Yamato, Suwa-shi, Seiko Epson Corporation (72) Inventor Akitaka Yajima 3-3-5 Yamato, Suwa-shi, Seiko Epson Corporation (56) References JP Sho-60- 41086 (JP, A) JP 58-172626 (JP, A) JP 60-179723 (JP, A) JP 60-120321 (JP, A)

Claims (1)

(57) [Claims] 1. A lighting means for generating a plurality of color lights, a plurality of liquid crystal panels for respectively modulating the respective color lights generated by the lighting means based on an image signal, and a color for each color light modulated by each of the liquid crystal panels. The color synthesizing unit for synthesizing and the projection optical unit for projecting the synthesized light color-synthesized by the color synthesizing unit are provided, and the plurality of liquid crystal panels undergo an odd number of reflections after being modulated, and then the projection optical unit. To modulate the color light guided to the first
A projection type display device comprising a liquid crystal panel of a type and a liquid crystal panel of a second type that modulates color light that is guided to the projection optical means after being modulated or not even reflected once, In each liquid crystal panel, liquid crystal is sealed between a pair of substrates, and on the inner surface of one of the substrates, a plurality of pixel electrodes arranged in a matrix and a plurality of signal lines to which the image signals are supplied are provided. A plurality of thin film transistors that supply the image signals supplied to the plurality of signal lines to the plurality of pixel electrodes are formed, and the inner surface of the other substrate shields the plurality of thin film transistors from incident color lights. A light-shielding layer is formed, and each of the liquid crystal panels sequentially assigns the image signals to the plurality of signal lines in the arrangement order of the signal lines, and assigns the assigned image signals. A liquid crystal panel of the first type, wherein each of the liquid crystal panels is arranged so that each color light enters from the other substrate side and is emitted from the one substrate side. Driver sequentially allocates the image signals to the plurality of signal lines to be arranged from one end side in the arrangement order, and the driver of the second type liquid crystal panel is arranged to the plurality of signal lines to be arranged. On the other hand, the projection display device is characterized in that the image signals are sequentially allocated from the other end side in the arrangement order.