JPH08163477A - Projection type liquid crystal display device - Google Patents

Abstract

PURPOSE: To realize a small sized projection type liquid crystal display device at a low cost by which an HDTV signal with a specific aspect ratio or a data signal of a square grating for a computer or the like is displayed selectively. CONSTITUTION: Liquid crystal light bulbs 50R, 50G, 50B with 1280 picture elements in the horizontal direction, 1024 picture elements in the vertical direction whose aspect ratio of picture element interval is a:1 are used to magnify an HDTV signal in the horizontal direction with an anamorphic lens 10 whose magnification is a:1 provided in front of a projection lens 20 and a pattern whose aspect ratio is 16:9 is displayed on a screen 60. A signal sampled from a data signal for a computer or the like coincident with picture elements of the signal is written coincident with the picture elements of the liquid crystal light bulbs 50R, 50G, 50B and magnified in the longitudinal direction by the anamorphic lens 10 and a square pattern is displayed on the screen 60.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection type liquid crystal display device for switching between an HDTV signal and a data signal for displaying on a CRT display such as a computer terminal and enlarging and projecting.

[0002]

2. Description of the Related Art Various projection type liquid crystal display devices using liquid crystal light valves have been put to practical use, and those called high definition display HDTV signals and data signals such as computer screens. There is something.

In HDTV signals, the aspect ratio of the screen is
As shown in FIG. 11, it is 16: 9.

On the other hand, in many cases, the data signal is generally assumed to be displayed in a so-called square lattice in which the interval between adjacent pixels is 1: 1 regardless of the aspect ratio of the screen. Also, many programs such as graphics are made on the premise of this condition.
FIG. 12 shows a display example of data signals of 1280 horizontal pixels and 1024 vertical pixels. The distance between the pixel 30 and the pixels in the vicinity thereof is an aspect ratio of 1: 1 as shown in FIG.
In the CRT type display device, such a condition can be satisfied by adjusting the amplitude with the deflection circuit. In the liquid crystal display device, it is possible to adjust the amplitude in the horizontal direction by changing the sampling frequency of the input signal. However, since it is a display device having a lattice structure, one pixel of the signal is on the display device. Depending on the position, it may be displayed with an inconstant number of pixels, such as 1 pixel or 2 pixels, or may be missing and not displayed at all, so that the visibility of characters may deteriorate and moire may occur. Was not.

Here, a projection type liquid crystal display device is used for decision making and presentation in a conference room or the like, and an HD
Assuming a case where a TV signal or a data signal is displayed in an enlarged manner, it is desirable that both can be switched and displayed on the same screen by one device in view of the utilization efficiency of the room.
When trying to realize such a projection type liquid crystal display device,
Since the aspect ratio of the screen is 16: 9 for HDTV signals and the square lattice is for data signals, the overall aspect ratio of the liquid crystal light valve used is 16: 9.
And the pixels need to be a square lattice. An example of such a liquid crystal light valve is shown in FIG. HDTV
Since there are 1035 effective scanning lines, the vertical direction of the liquid crystal light valve is 1035 pixels here. At this time, since it is a square lattice, the number of pixels in the horizontal direction is determined by the aspect ratio of the screen, which is 16: 9, and 1035 × 16 /
9 = 1840 pixels. When displaying an HDTV signal on such a liquid crystal light valve, all pixels are used for display, but the horizontal 1280 pixels shown in FIG.
To display a data signal of 1024 vertical pixels,
As indicated by reference numeral 31, the display is made by using only a part of the liquid crystal light valve.

[0006]

However, although the cost of the liquid crystal light valve generally increases as the number of pixels increases, the above-described data signal display method
Only about 70% of the liquid crystal light valve is used in the horizontal direction, which is extremely wasteful. Also, as HDTV uses all 1840 pixels,
A horizontal limit resolution of about 1000 TV lines can be obtained. However, for example, when displaying only MUSE signals or Unihigh output which is a standard of analog 1/2 inch VTR, 7
A resolution of about 00 TV lines is sufficient. Further, in a liquid crystal light valve, the writing speed is generally low, so parallel driving is performed. However, the number of parallel circuits for driving increases almost in proportion to the number of pixels in the horizontal direction, so it is necessary to keep the circuit scale small. It is better not to increase the number of pixels in the horizontal direction above. Further, the sampling clock of the input signal in the HDTV also increases almost in proportion to the number of pixels in the horizontal direction. Therefore, in order to reduce the operation speed of the circuit as much as possible, it is better not to increase the number of pixels in the horizontal direction more than necessary. Good.

Further, as an inherent property of the liquid crystal display device,
If the AC drive is not performed, the DC voltage is continuously applied and the life of the liquid crystal is shortened. Therefore, when the data signal is displayed as shown in FIG. 14, the region 32 where the signal is not displayed is displayed.
As for the above, all pixels must be AC-driven by writing a signal such as a black signal which is inconspicuous on the screen. If the blanking period of the data signal is long enough,
Since a black signal can be written by processing the blanking period in the same manner as the display period, there is no problem, but in the example of FIG. 14, there is 30% of the area 32 that is not displayed in the horizontal direction, and with a normal data signal, blanking is performed. Since the time for writing the black signal is insufficient only by the period, it is necessary to perform processing such as lengthening the equivalent blanking period due to time axis processing or the like, which is a factor that increases the circuit scale. .

Further, Japanese Patent Laid-Open No. 6-253242 describes that 16: 9 and 4: 3 video signals having different aspect ratios are switched and displayed by rotating an anamorphic lens, but only the aspect ratio of the screen is displayed. Focusing on, the magnification of the anamorphic lens is set,
No disclosure has been made on the method of dealing with the square lattice, which is the most important in displaying the data signal.

Further, Japanese Patent Laid-Open No. 4-170178 describes switching and displaying 16: 9 and 4: 3 video signals having different aspect ratios depending on whether or not the anamorphic lens is positioned on the optical axis. However, the method of displaying the data signal of the square lattice is not disclosed at all.

Therefore, according to the present invention, in a projection display device for selectively enlarging and projecting an HDTV signal and a data signal,
It is an object of the present invention to realize a projection type liquid crystal display device capable of displaying both the aspect ratio of an HDTV signal of 16: 9 and the data signal of a square lattice in a low cost and a small size.

[0011]

In order to solve the above problems, the invention according to claim 1 has an aspect ratio of pixel intervals of 1: 1.
The data aspect ratio is 1 and the aspect ratio of the screen is 1.
In a projection display device for selectively enlarging and projecting a 6: 9 HDTV signal, a PLL circuit that generates a clock that is a natural multiple of a dot clock that generates pixels of the data signal, and the data signal using the clock The liquid crystal light valve includes a sampling circuit for sampling, a liquid crystal light valve having a pixel arrangement in a lattice structure and a horizontal and vertical pixel interval ratio of a: 1, and an anamorphic lens rotatable about an optical axis. It is characterized in that it comprises a projection optical system for projecting the image displayed on, and the maximum value of the enlargement ratio in the orthogonal direction of the anamorphic lens is equal to a: 1.

The invention according to claim 2 is characterized in that, in the above-mentioned projection type liquid crystal display device, a = 1.1 to 1.2.

Further, according to the invention of claim 3, a data signal having an aspect ratio of pixel intervals of 1: 1 and an HDTV signal having a screen aspect ratio of 16: 9 are selectively enlarged and projected. In a projection display device, a PLL circuit that generates a clock that is a natural multiple of a dot clock that generates pixels of the data signal, a sampling circuit that samples the data signal at the clock, and a pixel array form a lattice structure. And a projection optical system for projecting an image displayed on the liquid crystal light valve, the liquid crystal light valve having a horizontal-to-vertical pixel interval ratio of 1: 1 and a removable anamorphic lens. It is characterized in that the maximum value of the enlargement ratio in the orthogonal direction is 1.4 to 1.5.

According to a fourth aspect of the present invention, the number of pixels of the liquid crystal light valve is 1280 pixels or more horizontally and 1 pixel vertically.
It is characterized by having 024 pixels or more.

[0015]

According to the first and second aspects of the present invention, an image of a liquid crystal light valve having a pixel interval of a: 1 and an enlargement ratio of a: 1.
Since the projection optical system including the anamorphic lens is used for projection, when displaying an HDTV signal, the aspect ratio of the screen can be set to 16: 9 by enlarging and projecting horizontally with the anamorphic lens. When displaying a signal, the image of the pixel of the liquid crystal light valve, which is sampled and written with a clock that is a natural multiple of the dot clock that generates the pixel of the input signal, is enlarged in the vertical direction and projected. Can display a 1: 1 square grid screen.

According to the third aspect of the invention, the pixel interval is 1:
Since the image of the liquid crystal light valve 1 is projected by the projection optical system in which the anamorphic lens can be attached / detached, when displaying an HDTV signal, the anamorphic lens is attached and the image is enlarged in the horizontal direction and projected. When the aspect ratio can be set to 16: 9 and the data signal is displayed, the image of the pixel of the liquid crystal light valve that is sampled and written with a clock that is a natural multiple of the dot clock that generates the pixel of the input signal, By removing the anamorphic lens and projecting, the pixel spacing is 1: 1.
You can display a square grid screen.

[0017]

【Example】

(Embodiment 1) An embodiment of a projection type liquid crystal display device according to the present invention will be described below with reference to the drawings.

A block diagram of a circuit of the projection type liquid crystal display device is shown in FIG.

HDTV signal 111 and data signal 112
Is selected by the input switching circuit 214 in response to a selection signal from the system control circuit 240 and input to the LPF 201 and the sync separation circuit 204. Sync separation circuit 204
Is a signal that separates the sync signal from the video signal 101. Generally, the HDTV signal 111 is separated from the luminance signal (Y) and the data signal 112 is separated from the G signal. Although not shown, the sync separation circuit 204 is not necessary and a circuit for switching the sync signal is needed. Separated horizontal sync signal 102
Is input to one input terminal of the phase comparator 205 that constitutes the PLL circuit 230.

The PLL circuit 230 includes a phase comparator 205,
It is composed of an LPF 206, a VCO 207, and a frequency dividing circuit 208. The phase comparator 205 has two input terminals,
The frequencies and phases of two input signals are compared, and a voltage corresponding to the difference is output. The output is input to the VCO 207 that controls the oscillation frequency by the voltage through the LPF 206, and the VCO 207 outputs the clock 104. The clock 104 is divided by the natural number N set by the system control circuit 240 in the frequency dividing circuit 208 and fed back to the phase comparator 205.

Since the horizontal synchronizing signal 102 is input to one input terminal of the phase comparator 205, the VCO 207
The clock 104, which is the output of, has a frequency N times that of the horizontal synchronization signal 102. Here, since the data signal 112 is generated based on the pixel clock in the computer that generates the data signal 112, the total value of the number of display pixels in the horizontal direction and the number of pixels corresponding to the horizontal blanking is divided as N. By setting the division ratio of the frequency divider circuit 208, the VCO 207 can generate the clock 104 that is equal to the pixel clock.

On the other hand, the output of the LPF 201 is output from the sampling circuit 202 and the A / D converter 203 by the clock 1
Sampling and quantization are performed by 04. It should be noted that in a normal LSI, the sampling circuit 202 and the A / D converter 203 are integrated, and both of them are combined into an A / D.
Often referred to as a converter. A / D converter 2
The output of 03 is input to the scan conversion circuit 209, and when the input signal is the HDTV signal 111, double speed conversion is performed from interlace to sequential scanning, and when the input signal is the data signal 112,
When the number of effective scanning lines is 1/2 or less of the number of pixels in the vertical direction of the liquid crystal light valve 50, double speed conversion for converting the same scanning line into two is performed, and in other cases, the same scanning line is directly output without conversion. Since the output of the scan conversion circuit 209 is driven in parallel to reduce the clock frequency, the phase expansion circuit 210
Is divided into a plurality of phases by the D / A converter 211, the analog signal is returned to the analog signal, and the analog processing circuit 212 performs inversion processing and level matching for AC driving.
15, and the horizontal driver 215 samples and holds the video signal for one line and writes it in the source line of the liquid crystal light valve 50.

Further, the timing circuit 213 has a horizontal / vertical synchronization signal 103 output from the synchronization separation circuit 204,
The clock 104 is input, and the horizontal driver 21 is set according to the setting from the system control circuit 240.
5. The vertical driver 216 has a clock (not shown)
Outputs start pulse of shift register. The output of the vertical driver 216 selects the gate line of the liquid crystal light valve 50, and writes the signal written in the source line to the pixel. Although FIG. 2 shows only one liquid crystal light valve, in the case of color, circuits for three colors and liquid crystal light valves may be provided.

FIG. 1 shows the internal structure of the projection type liquid crystal display device. The light source 51 is a high-luminance light source such as a metal halide lamp, and the emitted light is separated into three primary colors of R, G, and B by dichroic mirrors 52 and 53. The directions of the R light and the B light are changed by the mirrors 54, 55, and the mirror 56, and the R light, the G light, and the B light are respectively in the liquid crystal light valve 50.
It is incident on R, 50G, and 50B. Although omitted in the figure,
Polarizing plates are provided on both surfaces of the liquid crystal light valves 50R, 50G, and 50B, and brightness modulation is applied for each color by writing a video signal in the circuit of FIG. The R light, the G light, and the B light, which have been subjected to the brightness modulation, are combined by the dichroic prism 57 to form the projection lens 2 that constitutes the projection optical system.
0, the anamorphic lens 10 enlarges and projects a color image on the screen 60.

FIG. 3 shows an example of the anamorphic lens. The anamorphic lens is a lens formed by two cylindrical curved surfaces whose front and rear surfaces are parallel to each other, and has a convex shape and a concave shape, and FIG. 3 shows a concave shape. In each case,
The direction perpendicular to the cylindrical axis and the optical axis of the lens, FIG.
In, the thickness gradually changes along the horizontal direction. The concave type has a function of spreading the projection light in a single direction, and the convex type has a function of narrowing the projection light in a single direction. By providing these lenses on a part of the optical axis of the projection optical system, the aspect ratio and the conversion ratio of the pixel aspect ratio can be arbitrarily set. Further, although a single lens is shown in FIG. 3, there are many cases in which a plurality of lenses are attached to each other for achromatism, but the basic principle is the same.

The liquid crystal light valves 50R and 50G shown in FIG.
An example of 50B is shown in FIG. The number of pixels is 1280 pixels horizontally and 1024 pixels vertically, and the interval between the arbitrary pixel 40 and the pixels in the vicinity thereof is horizontal interval: vertical interval = 1.193: 1 as shown in FIG.

Here, with respect to the anamorphic lens 10, the enlargement ratio when the direction in which the thickness changes is set horizontally as shown in FIG. 3 is the horizontal enlargement ratio: vertical enlargement ratio = 1.193:
Set to 1.

When displaying an HDTV signal, the liquid crystal light valve is 1 for every 1035 effective scanning lines in the vertical direction.
Because of 024 pixels, about 1% is overscanned. Even in the horizontal direction, about 1% overscan is performed to balance with the vertical direction. That is, since the liquid crystal light valve has 1280 pixels, the effective scanning period is set to 1280 / 0.99 = about 1294 pixels, and the number of pixels corresponding to horizontal blanking, for example, 190.
The frequency dividing circuit 20 sets the total value 1484 of the pixels as the frequency dividing ratio N.
Set to 8.

The HDTV signal is mainly a natural image, and the signal is not generated by a specific pixel clock like a computer signal. Therefore, the band is limited by the LPF 201 to prevent aliasing distortion before sampling. Therefore, the frequency of the sampling clock 104 can be arbitrarily set in consideration of the number of horizontal pixels of the liquid crystal light valve, the overscan rate, the aspect ratio, and the like.

Here, when the anamorphic lens 10 is mounted coaxially on the front surface of the projection lens 20 and the direction in which the thickness changes is mounted horizontally, the screen on the screen 60 is compared with the case where the projection lens 20 alone projects. Since only the horizontal direction is multiplied by 1.193, the aspect ratio of the screen projected on the screen is 1.193 times in the horizontal direction.
Doubled,

[0031]

[Equation 1]

Thus, a screen matching the aspect ratio of HDTV as shown in FIG. 11 can be obtained.

Next, when displaying a data signal of 1280 horizontal pixels and 1024 vertical pixels as shown in FIG. 12 of the conventional example, the frequency dividing circuit 208 of FIG.
If the frequency division ratio N is set to 80 and the number of pixels corresponding to blanking, for example, 1600 which is the total value of 320 pixels, a clock having a frequency equal to the pixel clock generating the pixel of the data signal in the PLL circuit 230. Since it is possible to reproduce, it is possible to write one pixel of the input signal corresponding to one pixel of the liquid crystal light valve 50.

Here, when the anamorphic lens 10 is rotated by 90 degrees so that the direction in which the thickness of the anamorphic lens 10 changes is the vertical direction, projection is performed by 1.193 times in the vertical direction as compared with the case where only the projection lens 20 is used. Therefore, the distance between the adjacent pixels was 1.193: 1 on the liquid crystal light valve, but on the screen 60,

[0035]

[Equation 2]

Thus, a so-called square lattice is formed, and a screen display suitable for a data signal can be obtained.

Further, although not shown, a horizontal 6
In the case of a signal having 40 pixels and 480 pixels vertically, the number of pixels is doubled both horizontally and vertically. That is, in the vertical direction, if the scanning conversion circuit 209 performs double speed conversion so that the same scanning line becomes two lines, it can be displayed as a signal of vertical 960 pixels. In the horizontal direction, the number of display pixels is 640 pixels and the number of pixels corresponding to blanking, for example, a value 1 obtained by doubling the total value 800 of 160 pixels.
By setting 600 in the frequency dividing circuit 208 as the frequency dividing ratio N, one pixel of the input signal can be displayed as two pixels in the horizontal direction, that is, 1280 horizontal pixels.

In this way, one pixel of the input signal has twice the number of pixels in the horizontal and vertical directions, that is, 1280 pixels in the horizontal direction.
Since it can be displayed on the liquid crystal light valve 50 as vertical 960 pixels, when projection is performed with the direction in which the thickness of the anamorphic lens 10 changes is the vertical direction,
Compared with the case where only the projection lens 20 is used, only the vertical direction is multiplied by 1.193, so that it is possible to perform display satisfying the conditions of the square lattice as in the case described above. It should be noted that although omitted in FIG. 2 and the present description because it becomes complicated, if the scanning conversion circuit 209 performs double speed conversion, a clock having a double frequency is also required. The ratio is set to twice the above, and the scan conversion circuit 209
It is only necessary to divide the output of the VCO 207 into two and to give it to the earlier circuit, and the essential part of this embodiment does not change. Although not described in the present embodiment, changing the mounting direction of the anamorphic lens can be easily realized by a conventional technique such as a method of rotating with a motor. In the simplest case, the mechanism may be manually rotated by the user.

(Embodiment 2) FIG. 6 shows a liquid crystal light valve according to a second embodiment. Since the block diagram and internal structure of the circuit of the projection type liquid crystal display device are the same as those in the first embodiment, the description thereof will be omitted.

The liquid crystal light valve of FIG. 6 is a horizontal 1280
Pixels, vertical 1035 pixels, and the interval between an arbitrary pixel 41 and an adjacent pixel has an aspect ratio of 1.199:
It is 1.

Here, with respect to the anamorphic lens 10, the enlargement ratio when the direction in which the thickness changes is set horizontally as shown in FIG. 3 is the horizontal enlargement ratio: vertical enlargement ratio = 1.199:
Set to 1.

When displaying the HDTV signal, since there are 1035 effective scanning lines, it is possible to display in the vertical direction without overscanning the liquid crystal light valve. Therefore, even in the horizontal direction, the effective scanning period is 1
The number of pixels corresponding to 280 pixels, which is equivalent to horizontal blanking, for example, a total value 1466 of 186 pixels is set in the frequency dividing circuit 208 as the frequency dividing ratio N.

Here, when the anamorphic lens 10 is coaxially mounted on the front surface of the projection lens 20 and the direction in which the thickness is changed is horizontally attached and the image is projected, the screen on the screen 60 is compared with the case where only the projection lens 20 is projected. Then, since the horizontal direction is multiplied by 1.199, the aspect ratio of the screen projected on the screen is 1.199 in the horizontal direction.
Doubled,

[0044]

(Equation 3)

Thus, a screen matching the aspect ratio of HDTV as shown in FIG. 11 can be obtained.

Next, when displaying a data signal of 1280 horizontal pixels and 1024 vertical pixels as shown in FIG. 12 of the conventional example, the frequency dividing circuit 208 of FIG.
If the frequency division ratio N is set to 80 and the number of pixels corresponding to blanking, for example, 1600 which is the total value of 320 pixels, a clock having a frequency equal to the pixel clock generating the pixel of the data signal in the PLL circuit 230. Since it is possible to reproduce, it is possible to write one pixel of the input signal corresponding to one pixel of the liquid crystal light valve 50.

When the projection is performed by rotating the anamorphic lens 10 by 90 degrees so that the direction in which the thickness of the anamorphic lens 10 changes becomes the vertical direction, the vertical direction is 1.199 times larger than the case where only the projection lens 20 is used. Therefore, the distance between the adjacent pixels was 1.199: 1 on the liquid crystal light valve, but on the screen 60,

[0048]

[Equation 4]

Thus, a so-called square lattice is obtained, and a screen display suitable for a data signal can be obtained.

Although not shown in the figure, the horizontal 6
In the case of a signal having 40 pixels and 480 pixels vertically, the number of pixels is doubled both horizontally and vertically. That is, in the vertical direction, if the scanning conversion circuit 209 performs double speed conversion so that the same scanning line becomes two lines, it can be displayed as a signal of vertical 960 pixels. In the horizontal direction, the number of display pixels is 640 pixels and the number of pixels corresponding to blanking, for example, a value 1 obtained by doubling the total value 800 of 160 pixels.
By setting 600 in the frequency dividing circuit 208 as the frequency dividing ratio N, one pixel of the input signal can be displayed as two pixels in the horizontal direction, that is, 1280 horizontal pixels.

In this manner, one pixel of the input signal has twice the number of pixels in the horizontal and vertical directions, that is, 1280 pixels in the horizontal direction.
Since it can be displayed on the liquid crystal light valve 50 as vertical 960 pixels, when projection is performed with the direction in which the thickness of the anamorphic lens 10 changes is the vertical direction,
Compared with the case where only the projection lens 20 is used, only the vertical direction is multiplied by 1.193, so that it is possible to perform display satisfying the conditions of the square lattice as in the case described above. It should be noted that although omitted in FIG. 2 and the present description because it becomes complicated, if the scanning conversion circuit 209 performs double speed conversion, a clock having a double frequency is also required. The ratio is set to twice the above, and the scan conversion circuit 209
It is only necessary to divide the output of the VCO 207 into two and to give it to the earlier circuit, and the essential part of this embodiment does not change.

Although not described in the present embodiment, it is possible to easily change the mounting direction of the anamorphic lens by a conventional technique such as a method of rotating it with a motor. In the simplest case, the mechanism may be manually rotated by the user.

(Embodiment 3) FIG. 8 shows a liquid crystal light valve according to a third embodiment. Since the block diagram and internal structure of the circuit of the projection type liquid crystal display device are the same as those in the first embodiment, the description thereof will be omitted.

The liquid crystal light valve shown in FIG.
As shown in FIG. 9, the interval between an arbitrary pixel 42 and an adjacent pixel is a square lattice with an aspect ratio of 1: 1.

Here, the enlargement ratio of the anamorphic lens 10 when the direction in which the thickness changes as shown in FIG. 3 is set horizontally is as follows: horizontal enlargement ratio: vertical enlargement ratio = 1.422:
Set to 1.

When displaying an HDTV signal, the liquid crystal light valve is 1 for every 1035 effective scanning lines in the vertical direction.
Because of 024 pixels, about 1% is overscanned. Even in the horizontal direction, about 1% overscan is performed to balance with the vertical direction. That is, since the liquid crystal light valve has 1280 pixels, the effective scanning period is set to 1280 / 0.99 = about 1294 pixels, and the number of pixels corresponding to horizontal blanking, for example, 190.
The frequency dividing circuit 20 sets the total value 1484 of the pixels as the frequency dividing ratio N.
Set to 8.

Here, when the anamorphic lens 10 is mounted coaxially on the front surface of the projection lens 20 and the direction in which the thickness changes is mounted horizontally, the screen on the screen 60 is compared with the case where only the projection lens 20 is projected. Then, only the horizontal direction is multiplied by 1.422, so the screen 60
Above,

[0058]

(Equation 5)

Thus, a screen matching the aspect ratio of HDTV as shown in FIG. 11 can be obtained.

Next, when displaying a data signal of 1280 horizontal pixels and 1024 vertical pixels as shown in FIG. 12 of the conventional example, the frequency dividing circuit 208 of FIG.
If the frequency division ratio N is set to 80 and the number of pixels corresponding to blanking, for example, 1600 which is the total value of 320 pixels, a clock having a frequency equal to the pixel clock generating the pixel of the data signal in the PLL circuit 230. Since it is possible to reproduce, it is possible to write one pixel of the input signal corresponding to one pixel of the liquid crystal light valve 50.

If the anamorphic lens 10 is removed and the projection lens 20 alone is used for projection, the screen 6
Since the aspect ratio of the screen on 0 is the same as that of the liquid crystal light valve 50, the pixel spacing is also a square lattice, and a screen display suitable for the data signal can be obtained.

Although not described in this embodiment, the attachment and detachment of the anamorphic lens can be easily realized by the conventional technique such as providing a simple drive mechanism. In the simplest case, the user may manually attach and detach.

(Embodiment 4) FIG. 10 shows a liquid crystal light valve according to a fourth embodiment. Since the internal structure of the projection type liquid crystal display device is the same as that of the first embodiment, the description thereof will be omitted.

The liquid crystal light valve shown in FIG.
With 0 pixels and 1035 pixels in the vertical direction, the interval between the arbitrary pixel 43 and the adjacent pixel is a square lattice with an aspect ratio of 1: 1 as shown in FIG.

Here, the enlargement ratio of the anamorphic lens 10 when the direction in which the thickness changes as shown in FIG. 3 is set horizontally is as follows: horizontal enlargement ratio: vertical enlargement ratio = 1.438:
Set to 1.

When displaying an HDTV signal, since there are 1035 effective scanning lines, it is possible to display in the vertical direction without overscanning the liquid crystal light valve. Therefore, even in the horizontal direction, the effective scanning period is 1
The number of pixels corresponding to 280 pixels, which is equivalent to horizontal blanking, for example, a total value 1466 of 186 pixels is set in the frequency dividing circuit 208 as the frequency dividing ratio N.

Here, when the anamorphic lens 10 is coaxially mounted on the front surface of the projection lens 20 and the direction in which the thickness is changed is horizontally attached and the image is projected, the screen on the screen 60 is compared with the case where only the projection lens 20 is projected. Then, since only the horizontal direction is multiplied by 1.438, the screen 60
Above,

[0068]

(Equation 6)

As a result, a screen matching the aspect ratio of HDTV as shown in FIG. 11 is obtained.

Next, when displaying a data signal of 1280 horizontal pixels and 1024 vertical pixels as shown in FIG. 12 of the conventional example, the frequency dividing circuit 208 of FIG.
If the frequency division ratio N is set to 80 and the number of pixels corresponding to blanking, for example, 1600 which is the total value of 320, P
Since the LL circuit 230 can regenerate a clock having the same frequency as the pixel clock that is generating the pixel of the data signal, one pixel of the input signal is regenerated by the liquid crystal light valve 5.
It is possible to write in correspondence with one pixel of 0.

If the anamorphic lens 10 is removed and the projection lens 20 alone is used for projection, the screen 6
Since the aspect ratio of the screen on 0 is the same as that of the liquid crystal light valve 50, the pixel spacing is also a square lattice, and a screen display suitable for the data signal can be obtained.

Although not described in this embodiment, the attachment and detachment of the anamorphic lens can be easily realized by the conventional technique such as providing a simple drive mechanism. In the simplest case, the user may manually attach and detach.

[0073]

As described above, according to the first and second embodiments of the present invention, it is only necessary to change the mounting angle of the anamorphic lens by 90 degrees depending on the HDTV and the data signal.
It is possible to display a screen which satisfies both conditions of a screen aspect ratio of 16: 9 in a DTV and a square lattice in a data signal.

At this time, if the number of pixels in the horizontal direction of the liquid crystal light valve is 1280 pixels or more in the horizontal direction, the resolution in the horizontal direction in HDTV becomes about 720 TV lines or more, and the MUS
Sufficient resolution can be obtained to display the E signal and the Uni-high VTR signal.

Further, in the third to fourth embodiments, the liquid crystal light valve of the square lattice is used, and the anamorphic lens is used to horizontally expand only for the HDTV signal. The signal can display a screen that satisfies both conditions of the square lattice.

Further, in any of the above-described embodiments, even in the case of a data signal having an aspect ratio longer than that of HDTV, a large area for not displaying the signal is not required on the liquid crystal light valve. Since it is possible to effectively use the liquid crystal light valve, it is not necessary to use a liquid crystal light valve having more pixels than necessary, and the light valve itself can be reduced in cost.

Further, a phase expansion circuit 21 for parallel driving is provided.
The number of circuits after 0 is 12 for one circuit of the horizontal driver 215.
When driving 8 pixel output, the aspect ratio is 16: 9
And the horizontal direction corresponding to the case where the pixel is a square lattice is 1840
The number of circuits required for 15 pixels is reduced to 10 circuits for 1280 pixels. Further, since the sampling frequency in the case of HDTV can be reduced to about 0.7 times in proportion to the number of pixels in the horizontal direction, it is possible to reduce the cost of the device used. Further, the time axis processing for extending the blanking period becomes unnecessary.

Since there are many effects as described above, according to the present invention, a projection type liquid crystal display device capable of switching display between HDTV and a data signal can be realized at low cost and in a small size.

[Brief description of drawings]

FIG. 1 is a diagram showing an internal structure of a projection type liquid crystal display device of the present invention.

FIG. 2 is a diagram showing a block diagram of a circuit of the projection type liquid crystal display device of the present invention.

FIG. 3 is a diagram showing an anamorphic lens of the present invention.

FIG. 4 is a diagram showing a liquid crystal light valve of a first embodiment of the present invention.

FIG. 5 is a diagram showing a pixel of the liquid crystal light valve according to the first embodiment of the present invention.

FIG. 6 is a diagram showing a liquid crystal light valve according to a second embodiment of the present invention.

FIG. 7 is a diagram showing pixels of a liquid crystal light valve according to a second embodiment of the present invention.

FIG. 8 is a diagram showing a liquid crystal light valve of a third embodiment of the present invention.

FIG. 9 is a diagram showing pixels of a liquid crystal light valve according to third and fourth embodiments of the present invention.

FIG. 10 is a diagram showing a liquid crystal light valve according to a fourth embodiment of the present invention.

FIG. 11 is a diagram showing an aspect ratio of an HDTV screen.

FIG. 12 is a diagram showing a display example of a conventional data signal.

FIG. 13 is a diagram showing a pixel of a conventional data signal.

FIG. 14 is a diagram showing an example of a conventional liquid crystal light valve.

[Explanation of symbols]

 10 Anamorphic Lens 20 Projection Lens 30 Pixel 31 Data Signal Display Area 32 Data Signal Not Displayed Area 40, 41, 42, 43 Pixel 50, 50R, 50G, 50B Liquid Crystal Light Valve 51 Light Source 52, 53 Dichroic Mirror 54, 55, 56 Mirror 57 Dichroic prism 60 Screen 101 Video signal 102 Horizontal sync signal 103 Horizontal / vertical sync signal 104 Clock 111 HDTV signal 112 Data signal 201 LPF 202 Sampling circuit 203 A / D converter 204 Sync separation circuit 205 Phase comparison circuit 206 LPF 207 VCO 208 Frequency divider circuit 209 Scan conversion circuit 210 Phase expansion circuit 211 D / A converter 212 Analog processing circuit 213 Timing circuit 214 Input switching circuit 2 15 horizontal driver 216 vertical driver 230 PLL circuit 240 system control circuit

Claims (4)

[Claims] 1. A data signal having an aspect ratio of pixel intervals of 1: 1 and an HDT having a screen aspect ratio of 16: 9.
In a projection display device for selectively enlarging and projecting a V signal, a PLL circuit that generates a clock that is a natural multiple of a dot clock that generates pixels of the data signal, and a sampling circuit that samples the data signal at the clock And a liquid crystal light valve in which the pixel arrangement has a lattice structure and a horizontal and vertical pixel interval ratio is a: 1, and an anamorphic lens rotatable about the optical axis is displayed on the liquid crystal light valve. A projection type liquid crystal display device, comprising a projection optical system for projecting an image, wherein the maximum value of the magnification ratio of the anamorphic lens in the orthogonal direction is equal to a: 1. 2. The projection type liquid crystal display device according to claim 1, wherein a = 1.1 to 1.2. 3. A data signal having an aspect ratio of pixel intervals of 1: 1 and an HDT having a screen aspect ratio of 16: 9.
In a projection display device for selectively enlarging and projecting a V signal, a PLL circuit that generates a clock that is a natural multiple of a dot clock that generates pixels of the data signal, and a sampling circuit that samples the data signal at the clock And a projection for projecting an image displayed on the liquid crystal light valve, which includes a liquid crystal light valve having a pixel arrangement in a lattice structure and a horizontal and vertical pixel interval ratio of 1: 1 and a removable anamorphic lens. The anamorphic lens is composed of an optical system, and the maximum value of the magnifying power ratio in the direction perpendicular to the anamorphic lens is 1.4.
A projection type liquid crystal display device, characterized in that 4. The projection type liquid crystal display device according to claim 1, wherein the number of pixels of the liquid crystal light valve is 1280 pixels or more in the horizontal direction and 1024 pixels or more in the vertical direction.