JPS6326626A - Multicolor liquid crystal display device - Google Patents

Abstract

PURPOSE:To easily adjust a color shift by providing projection lens by colors and providing each projection lens with an enlargement magnification varying mechanism and a position adjusting mechanism which moves and adjust the position in a plane perpendicular to an optical axis. CONSTITUTION:Focus adjusting rings 101a-101c of the respective projection lenses 100a-100c are adjusted to form images on a screen sharply. Then, three images are made coincident to obtain one multicolor image. When the image formed in the respective colors are different in size, they are adjusted by using the enlargement rate adjusting rings 102a-102c of the respective projection lenses, thereby equalizing those images in size as the 1st stage. The projection lenses 100a-100c are moved in the planes perpendicular to the optical axes and micrometers 103a-103c and 104a-104c for fine movement are used as the 2nd stage. Consequently, the images of red, green, and blue are obtained and even if those images shift in position owing to vibrations, etc., they can be adjusted immediately.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multicolor liquid crystal display device that enlarges and projects a color image onto a screen by utilizing the thermo-electro-optic effect of a liquid crystal element.

[Conventional technology]

Conventionally, there has been known a device that uses the thermo-electro-optic effect of smectic liquid crystal to write a desired image on the liquid crystal using the thermal energy of a laser beam, and then enlarges and projects the image onto a screen using a projection optical system. (Japanese Unexamined Patent Publication No. 51-52233).

FIG. 15 is a schematic diagram showing the conventional configuration of a projection optical system in such an apparatus, in which red, green, and blue color lights g3o1,
The light emitted from 302 and 303 passes through lenses 304 and 305.
, 306 and parallel light beams 307, 308, 3, respectively.
After being converted to 09, reflection vt310, 311, 312
are reflected by liquid crystal elements 313, 314,
315. Then, when the incident light beam passes through each liquid crystal element, it captures a previously written image as light and shade of light. In this way, each liquid crystal element 313.3
The light beam transmitted through 14 and 315 is reflected by mirrors 316 and 31.
7, 318, the beam becomes one beam 319 and enters the projection lens 320.

The image is magnified by the projection lens 320 and projected onto the screen 321. As a result, a color image with a combination of red, green, and blue colors is displayed on the screen 321.

- By the way, in a configuration in which an image is obtained using such an optical system, color shift of the image occurs due to the first-order cause.

(a) Blurred image and difference in magnification due to chromatic aberration (b) Difference in magnification due to error in distance between the projection lens and liquid crystal element (c) Parallelism of image due to tilt or positional deviation of optical elements such as the projection lens and reflector For example, moving.

Chromatic aberration can be divided into longitudinal chromatic aberration and lateral chromatic aberration. Longitudinal chromatic aberration is a shift in the imaging position in the optical axis direction depending on the color. In other words, since the position where the image is formed by the projection lens differs depending on each color, for example, if you try to form a clear image of red on the screen, the image formation plane of blue will be misaligned with the screen, resulting in a blurred image. become. It is known that this longitudinal chromatic aberration can be eliminated to some extent by introducing a lens called an achromatic lens using a combination lens. However, the magnification for enlarging the finely written image on the screen using a laser on the liquid crystal element is 50 to 10.
Since a projection lens with 0x and high magnification is required, aberrations at the periphery of the screen cannot be ignored, and the red color
Under the conditions of imaging a dot, the blue dot is 3~4+am
I'm confused.

Another type of lateral chromatic aberration is that the focal length differs depending on the color, resulting in a difference in image magnification, and this cannot be eliminated with an achromatic lens. As mentioned above, a projection lens with a high magnification of 50 to 100 times must be used, and the influence of this lateral chromatic aberration is about several meters to 10 mm around the periphery of the screen. Therefore, due to chromatic aberration, a clear image can only be obtained at the center of the screen (see U.S. P. 4,368,963) [Problem to be solved by the invention] However, in the conventional configuration, the above color shift occurs. Because there is no consideration given to the color shift, if a color shift occurs in the image on the screen, all the optical systems placed before the projection lens must be adjusted, which is extremely troublesome. Furthermore, when replacing the liquid crystal element, etc., the work must be carried out so as not to apply vibration to each optical element, and there is a problem that maintenance and inspection are not easy.

Furthermore, since it is necessary to avoid applying vibration to each optical element, there is a problem that the optical element cannot be mounted on a moving vehicle or the like, and the installation position is limited.

The purpose of the present invention is to easily adjust color shift,
Moreover, it is an object of the present invention to provide a multicolor liquid crystal display device whose installation position can be freely selected.

[Means for solving problems]

The present invention provides projection lenses for different colors.

Each projection lens has a variable magnification mechanism and a position 5 for adjusting the position within a plane perpendicular to the optical axis! It is equipped with an adjustment mechanism.

[Effect]

By providing a projection lens for each color that has no longitudinal chromatic aberration at the center wavelength of each color, one color shift is eliminated.

Furthermore, by varying the magnification, deviations in image size caused by lateral chromatic aberration are eliminated. Furthermore, by adjusting the position of the projection lens in a plane parallel to the screen,
It is possible to match the image formation positions for all colors due to the inclination or positional shift of optical elements such as reflective mirrors.

(Example〕 Hereinafter, the present invention will be specified based on Examples.

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, in which semiconductor laser oscillators 1a and 1b are provided which oscillate and output a laser beam with a wavelength of about 82 Onm.

Further, the laser beams output from the semiconductor laser oscillators 1a, lb are elliptical, diffused beams, and collimating lenses 2a, 2b with large apertures and small difference in number are provided in order to introduce them into the optical system. There is. The laser beams 3a and 3b that have passed through the collimating lenses 2a and 2b have an elliptical cross section as shown in FIG. Since laser beams are suitable, laser beams 5a and 5b having circular cross sections are formed by beam shaping optical systems 4a and 4b using cylindrical lenses or prisms.
is converted to Here, semiconductor laser oscillators 1a, lb
The laser beam outputted from the laser beam is linearly polarized in the minor axis direction of the laser beam having an elliptical cross section as shown by the arrow in FIG. 2, and the degree of polarization is 100:1 or more. Further, this polarization direction is perpendicular to the current injection direction in the laser chip.

Utilizing this polarization characteristic, the light beams are combined into a single laser beam 7 using a polarization beam splitter 6.

In this case, the polarization direction of the transmitted laser beam 5a is parallel to the plane of the paper (arrow), and the direction of polarization of the reflected laser beam 5b is perpendicular to the plane of the paper (point). The laser beam 7 thus synthesized is expanded by a beam expander 8 to become a thick laser beam 9 of about 30 amφ. The laser beam 9 is two-dimensionally scanned by a galvanometer mirror 10 and 1°1, converted into a convergent laser beam 13 by an f-θ lens 12, and converted into three convergent laser beams 15a and 15b with equal power by a three-split optical system 14.

After being divided into 15c, a liquid crystal element 16a is filled with a cyanobiphenyl smectic mixed liquid crystal.

16b and 16c are irradiated. The f-θ lens 12 has a focal length f = 240 m+* and a brightness F/8, and the diameter of the condensed beam on the liquid crystal element is about 10 μm. The structure of the liquid crystal element will be described later. The above is a writing optical system for writing an image on a liquid crystal element using a laser beam. The image written on the liquid crystal element by this writing optical system is enlarged and projected onto a screen by a projection optical system, which will be described below. This projection optical system is provided independently for each of the three liquid crystal elements and has the same configuration. Therefore, only the optical system for projecting a red image will be described below as a representative example.

Light generated from a light source 17, which is a red light source or a white light source such as a xenon lamp, colored by a filter, is converted into a red light beam 19 by a lens 18, and then a half mirror.
20 and irradiates the liquid crystal element 16a. Liquid crystal element 1
The light beam reflected by the reflective film 6a captures the written image in light and dark shades, passes through the half mirror 20, and is enlarged and projected onto the screen 22 by the projection lens 21, thereby displaying a red image. . The green image is liquid crystal element 1
The image written on the screen 6b is similarly projected onto the screen 22 by the projection optical system 23, and the blue image is displayed on the liquid crystal element 16c.
The image written on the screen 22 is similarly projected onto the screen 22 by the projection optical system 24.

A control device 30 generates signals for writing images corresponding to red, green, and blue into the liquid crystal elements 16a, 16b, and 16c using laser beams.

The control device 30 includes laser control signals 31a and 31b for controlling the semiconductor laser oscillators 1a and 1b, and a galvanometer mirror 1.
0 and 11, and these signals control the generation and scanning of the laser beam, and scan the liquid crystal elements 16a to 16c in an arbitrary pattern, as well as the color desired to be displayed on the screen. A color signal voltage is applied to the liquid crystal element corresponding to the color signal. That is, when it is desired to draw a red image on the screen, a color signal 34a connected to the liquid crystal element 16a is output. If it's green, it's 34b.

When a 0 color signal is applied that outputs 34c in the case of blue, even if the laser beam scans the liquid crystal element, it returns to its original transparent state, and the desired color light is reflected and displayed. FIG. 3 shows the cross-sectional structure of the liquid crystal element.

A glass substrate 50 with a thickness of 2 mm has an anti-reflection film 51 for the oscillation wavelength of the semiconductor laser oscillator deposited on one side, and chromium oxide, chromium, and phthalocyanine for absorbing the semiconductor laser beam and converting it into heat on the other side. A reflective film 53 made of aluminum or the like which serves as a visible light reflective film and an electrode, and an alignment film 54 made of an organic film such as fluorosilane or silicon oxide obliquely deposited to orient the liquid crystal. It is provided. The other opposing glass substrate 55 is provided with an anti-reflection film 56 against visible light, and the opposite surface is provided with a transparent electrode 57 made of indium oxide or the like and an 11% 5B orientation.

These two glass substrates 5o and 55 face each other via a seal 59 that controls the thickness of the liquid crystal layer, and a smectic liquid crystal 60 mainly composed of cyanobiphenyl organic matter is sealed therein. More than 90% of the laser beam 61 is absorbed by the laser absorption film 52 and becomes heat. This heat is transferred to the smectic liquid crystal 60, and
Raise the temperature of 0 to cause a phase transition and create an isotropic liquid state.

When the irradiation of the laser beam 61 is stopped and the color signal generated by the signal source 62 is applied between the reflective film 53 and the transparent electrode 57 when cooling from the isotropic liquid state, the color signal returns to the original transparent state 63 and is not applied. In this case, it shows a scattering state 64.The range showing this scattering state 1rIA64 is limited to the range heated by the laser beam 61 and turned into an isotropic liquid state, so the beam spot diameter of the laser beam 61 is set to 10μ.
It is possible to write an image with a dot size of about 10 μm. The written image is read out by a visible light beam 65. In the present invention, this light beam 65 is reflected by a reflective film 53, and the reflected light is captured by a projection lens (FIG. 1, 21) and magnified onto a screen 22. Project.

In the present invention, three liquid crystal elements are used, one for red and one for green.

One laser beam scanning mechanism scans images corresponding to blue.
Write to two liquid crystal elements at the same time.

Next, referring to FIG. 4, a three-division optical system that divides one laser beam into three and writes on three liquid crystal elements will be described. The two-dimensionally scanned laser beam 80 is f-θ
The lens 70 forms a convergent laser beam 81. This convergent laser beam 81 is split by a beam splitter 71 into a transmitted laser beam 82 and a reflected laser beam 83. The beam splitter 71 has a prism shape, and is a combination of two rectangular prisms made of BK7, with a semi-transparent film 72 of a dielectric multilayer film attached to the joint surface. The characteristics of the semi-transparent film 72 are as follows: wavelength SOO~830 nm, transmittance ratio = 2:
The zero reflected laser beam 83 set to 1 is reflected by the prism-shaped reflecting mirror 73 and made parallel to the transmitted laser beam 82 . The transmitted laser beam 82 is split again by the beam splitter 74 into a transmitted laser beam 84 and a reflected laser beam 85. The beam splitter 74 has the same structure as the beam splitter 71, and the characteristics of the semi-transparent film 75 are transmittance:reflectance=1:1 in the wavelength band.The zero reflected laser beam 85 is reflected by the prism-shaped reflecting mirror 76. Transmitted laser beam 84 and barbaric treatment. The transmitted laser beam 84 is reflected in a zigzag manner by two prism-shaped reflecting mirrors 77 and 78, and is made to have the same optical path length as the two reflected laser beams. From the above, three parallel convergent laser beams with equal power are obtained, and the focal points of these three convergent laser beams are Δ-shaped and on the same plane. Three liquid crystal elements 79a, 79b, and 79c are arranged at this focal point. Therefore, the three liquid crystal elements are simultaneously scanned with a laser beam of the same power in the same pattern. Whether or not a laser beam scan locus is left as a scattering state on the liquid crystal element depends on the presence or absence of a voltage applied to the liquid crystal element from the outside as described above.

The image written on the liquid crystal element is enlarged and projected onto a screen by a projection optical system. There are three sets of projection optical systems with the same configuration, and each set is three-dimensionally arranged so as not to interfere with each other. In Figure 4, the light g 90 a , 9
0 b, 90 c and half mirrors 91a, 91b,
91c, and a projection lens 92a.

92b and 92c are shown. The light beam 93a output from the light source 90a is reflected by the half mirror 91a and irradiated onto the liquid crystal element 84a.As described above, the light beam 93a is reflected by the aluminum film in the liquid crystal element.
91a, and an image on a liquid crystal element is formed on a screen by a projection lens 92a.

Next, how to match images on the screen will be explained below. FIG. 5 is a side view of a unit of the projection optical system, and FIG. 6 is a front view. The projection lenses 100a to 100c are arranged in a Δ shape when viewed from the front. Each projection lens 100
Focus adjustment rings 101a to 101c are included in a to 100c.
and magnification adjustment rings 102a to 102c, horizontal fine movement micrometers 103a to 103c, and vertical fine movement micrometers 104a to 104c, respectively.

In order to match the image forming points on the screen, first adjust the focus adjustment ring 101a of each projection lens 100a to 100c.
~101c is adjusted to form a clear image on the screen.The three images are made to coincide with each other to obtain one multicolor image. In the first stage of image matching, if there is a difference in the size of images formed by each color, the sizes of the images are made to match. For this purpose, the magnification adjustment rings 102a to 102c of each projection lens are used for adjustment. The standard for the size of the image is to write a preset pattern on the liquid crystal element and make the size on the screen match the design value. 7th
In the figure, a square is set as a reference pattern, and the designed size is shown by a solid line.

If the actually formed images are small as shown by the broken line, they are enlarged in the direction of the arrow in the figure to make them coincide. The second stage of adjustment is to match the three images.

This is done by moving the projection lenses 100a to 100c within a plane perpendicular to the optical axis. This movement is performed by micrometers 103a to 103c and 104a to 104c for fine movement attached to the projection lenses 100a to 100c. In Fig. 8, the designed position is shown by a solid line, and the actual image is shown by a broken line.
03a~103ct-Adjust and move/move the image in the horizontal direction Micrometers for vertical fine movement 104a~104
Red, green, and blue images are obtained by one or more adjustments that adjust c to g and move the image vertically to match the reference position.

With such adjustment, even if a shift occurs in the image due to vibration or the like, it can be immediately adjusted.

The optical system explained above consists of a writing optical system and a projection optical system.
It is installed in two units and separated from the screen. The state will be explained below. FIG. 9 shows an example of the arrangement applied to a front projection screen.

The distance between the screen 150 and the optical unit 151 is changed depending on the desired screen size on the screen, and is approximately 6 m when the screen size on the screen is 2 m square. Since the front projection screen is a reflective screen, the adjuster can make adjustments while standing on the optical unit side.

FIG. 10 shows an example of application to a rear projection screen. The optical unit 151 is installed in front of the rear projection screen 152, and projects an image from the rear of the screen 152 using two large mirrors 153 and 154. With this arrangement, the adjuster can easily make adjustments while viewing the image on the screen. Further, by installing the optical unit 151 under the floor or in a suitable stand, the installation area can be reduced, and the space behind the rear projection screen can also be reduced.

FIG. 11 shows an example of an apparatus in which everything from an optical unit to a rear projection screen is integrated. There is no drawer in front of the screen, and the optical unit 151 is installed behind the rear projection screen 152, and projects onto the folded screen 154 using two mirrors 153 and 154. In this case, it is difficult for the adjuster to see the image on the screen. Therefore, a finely movable motor (not shown) is provided in the adjustment portion of the projection lens, and this motor is remotely controlled by a remote control device 155, thereby making it possible to adjust the magnification of the projection lens, etc. The remote control bag W155 includes levers 160a and 160b for moving the image horizontally and vertically in order to independently adjust the projection lens for each color.

160c, magnification adjustment switch 161a *16
1b, 161c, focusing switch 162a.

162b and 162c are provided. The position of the image can be moved for each color in both the X direction and the Y direction by levers 160a to 160c. Further, each of the enlargement magnification adjustment switches 161a to 161c is provided with a button switch for adjusting the enlargement direction and the reduction direction, and the focusing switches 1628 to 16
Each of the lenses 2c is provided with two button switches for moving the projection lens back and forth on the optical axis.

By using such a remote control device, it is possible to easily adjust the image shift etc. at any position away from the display bag's installation position. Such remote control is shown in Figures 9 and 1.
It can also be easily applied to the configuration shown in FIG. Note that in the configurations shown in FIGS. 10 and 11, two reflecting mirrors are used.

It goes without saying that the optical path can be changed freely by using any number of reflecting mirrors, taking into account the size and shape of the installation location.Also, although a laser beam with a wavelength of 800 to 830 nm is used, it is possible to use other wavelength bands. Even if there is one, it can be used freely by matching it with the characteristics of the writing optical system. In addition, colored light sources are used for projection, but
A configuration in which a color filter is provided in the optical path leading to the projection lens using a white light source, or a configuration in which a color filter is attached to the projection lens may be used.Furthermore, one color can be freely selected, not limited to red, green, and blue. , and the color combination can be two or four or more colors.

Furthermore, although color shift adjustment is performed by displaying a reference pattern on the screen, as shown in FIG.
Adjustment dots or circular patterns 202a to 202d are projected onto the four corners of this area 201, and the circular pattern 20 is projected as shown in the enlarged view of FIG.
A color sensor 203 larger than 2 is attached, and a circular pattern 300r of red, green, and blue is attached as shown in FIG.

If these patterns are misaligned when 300g and 300b are projected, it is possible to adjust the color shift by adjusting the pattern so that it becomes one circular pattern 301 as shown in FIG. 14(b). good.

[Effects of the Invention] As explained above, according to the present invention, color misregistration can be easily adjusted, so alignment work when assembling the optical system can be performed easily and in a short time. ,
Even when vibrations occur, clear images can be displayed by simple color shift adjustment. Furthermore, even if the sizes of the images of each color written on the liquid crystal element are different, the sizes can be matched and displayed.

[Brief explanation of drawings]

No. 1 is an overall configuration diagram showing an embodiment of the present invention. Figure 2 is a perspective view for explaining the cross-sectional shape of the laser beam after passing through the collimating lens, Figure 3 is a cross-sectional view of the liquid crystal element, Figure 4 is an overall configuration diagram of the writing optical system, Figures 5 and 6. The figures are a sectional view and a front view of the projection optical system, Figures 7 and 8 are explanatory diagrams when performing image alignment, and Figures 9 to 1.
FIG. 1 is an arrangement diagram showing an example of a combination arrangement of an optical unit and a screen. FIGS. 12 to 14 are explanatory diagrams for explaining another example of a method for adjusting image shift, and FIG. 15 is a schematic diagram of a conventional projection optical system. 1... Semiconductor laser, 2... Collimator lens, 4
. . . Beam shaping optical system, 6 . . Polarizing beam splitter, 8 . ...Liquid crystal element, 17...Light source, 18...
- Lens, 20... Half mirror 121... Projection lens, 22... Screen, 30... Control device.

Claims (1)

[Claims] 1. Color-specific liquid crystal elements on which desired images are written using the thermal energy of the laser beam, and visible light beams are projected onto these color-specific liquid crystal elements to create a pre-written image. A multi-color liquid crystal display device comprising a color-specific projection optical system that extracts light and light of gradation corresponding to a loaded image and forms an image on the same screen through a projection lens common to each color. A multicolor liquid crystal display device, characterized in that lenses are provided for each color, and each projection lens is provided with a variable magnification mechanism and a position adjustment mechanism for moving and adjusting the position within a plane perpendicular to the optical axis.