JP2537911B2 - Projection type liquid crystal display panel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A projection type color liquid crystal display panel for a large screen display using a phase transition type liquid crystal as a light valve, and more particularly to a panel structure for preventing deterioration of color display quality due to pixel shift. Type color liquid crystal display panels are stacked. The display pixels (dots) corresponding to each other in each liquid crystal panel are configured to surely overlap with each other in projection display to prevent pixel shifts. A liquid crystal display panel in which at least two different liquid crystal panels are laminated, and the transmittance of the liquid crystal layer of each of the laminated liquid crystal panels is controlled to project a multicolor dot display by irradiation light from the panel back surface of the first layer. For the dot shape of the first liquid crystal panel and its arrangement interval,
The dot shapes and the arrangement intervals of the liquid crystal panels of the second layer and above are sequentially reduced.

[Industrial applications]

The present invention relates to a projection type color liquid crystal display panel for a large-screen display using a phase transition type liquid crystal as a light valve, and more particularly to a panel structure for preventing deterioration of color display quality due to pixel shift.

As a large-screen display, a projection display method using a high-brightness CRT, a laser, or a light valve, etc., has already been put into practical use instead of a blackboard or an overhead projector (OHP), but these are all highly accurate optical systems. Since it is used, there is a problem that it is not popular because it is expensive.

Under such circumstances, recently, a projection type liquid crystal display panel for a large screen display using a phase transition type liquid crystal (mixed liquid crystal of nematic liquid crystal and cholesteric liquid crystal) as a light valve has been proposed.

Originally, the mainstream of this projection type liquid crystal display panel was black and white display, but since then, color information has been developed due to the diversification of information, and a panel structure that enables color display without picture element displacement is required. ing.

[Conventional technology]

The projection type monochrome display panel using the phase transition type liquid crystal is
As shown in FIGS. 1A to 1C, a pair of transparent substrates 1a and 1b each having a transparent electrode (not shown) coated with an alignment film on the inner surface thereof are arranged to face each other at a predetermined interval. The phase transition type liquid crystal 2 is filled between 1b, and information is displayed by utilizing the hysteresis phenomenon of light transmittance based on the phase transition phenomenon of the nematic / cholesteric phase transition type liquid crystal 2.

The principle of operation is that when a high voltage is applied to the electrodes of the pair of transparent substrates 1a and 1b, the liquid crystal molecules in the phase transition type liquid crystal layer 2 follow the electric field as shown in FIG. 7 (b). And is oriented perpendicular to the opposing substrates 1a and 1b to be in a transparent state of a nematic phase, and the incident light is collected and projected by the projection lens 3 to be in a bright state on the opposing screen (not shown). 2a represents liquid crystal molecules aligned vertically.

Further, when the applied voltage is lowered, as shown in FIG. 7 (c), the liquid crystal molecules are helically aligned by their own force and undergo a phase transition to a cholesteric phase, which causes a light scattering state and the incident light is scattered. The projection lens 3 does not collect light, and the screen (not shown) facing the display lens 3 is in a dark state. 2b is a liquid crystal molecule oriented in a spiral winding.

Therefore, the phase transition type liquid crystal display panel 11 is mounted on the OHP 12 as shown in FIG. 8, the irradiation light from the light emitting source 13 is irradiated through the condensing lens 14 such as a Fresnel lens, and After the display information is written using the phase transition state, the information is enlarged on the screen 16 in two black and white states of the nematic phase H ′ and the cholesteric phase F by the projection unit 15 by applying the bistable sustaining voltage Vd. And projection display.

On the other hand, a method has also been proposed in which the helical pitch of the liquid crystal is controlled by the material composition so that the transmitted light with respect to the liquid crystal has wavelength dependence and color display is performed.

A color liquid crystal display panel according to this method includes, for example, a first liquid crystal panel having a display color that makes a phase transition from a white transparent state to a red scattering state and a first liquid crystal panel having a display color that makes a phase transition from a white transparent state to a green scattering state. It has a structure capable of multi-color display by superimposing two liquid crystal panels, and by mounting this on the OHP12 in the same manner as described with reference to FIG. 8, enlarged display of color information is possible.

[Problems to be solved by the invention]

By the way, as shown in FIG. 9 (a), the first liquid crystal panel 22 having a display color that makes a phase transition from the white transparent state to the red scattering state and the display color that makes a phase transition from the white transparent state to the green scattering state When the display picture elements of the two-layer structure color liquid crystal display panel 21 in which the second liquid crystal panel 23 is laminated have a dot matrix configuration, the transmittance of the liquid crystal layers of those panels is controlled, and the irradiation light from the light emitting source 13 is controlled. When the light emitted from the display panel 21 is projected on the opposing screen 16 via the projection lens 15a and dot display is performed by making the light incident from the back surface of the panel through the condensing lens 14 formed of a Fresnel lens. In addition, since the projection magnification in the panel peripheral portion is different due to the thickness of the substrate of each liquid crystal panel 22, 23 and the difference in the distance between the projection lens 15a and each liquid crystal panel 22, 23, etc. Projected first Dot pattern B of the second liquid crystal panel 23 is superimposed in a state where the pattern shift occurs as indicated by a broken line corresponding relative dot pattern A of the liquid crystal panel 22.

That is, further explaining this phenomenon with reference to FIG. 9 (b), the picture elements of the first liquid crystal panel 22 which are arranged at a predetermined interval d and each height is X ₁ Y ₁ = X ₂ Y _2. When the (dot) a and the picture element b (dot) of the second liquid crystal panel 23 are superimposed and projected on the screen 16 facing each other through the projection lens 15a, the distance between the picture element a and the projection lens 15a and the picture element b From the difference (a0> b0) between the projection lenses 15a, the relationship between the projection pattern A of the picture element a and the projection pattern B of the picture element b on the screen 16 is X ₁ ′ Y ₁ ′ <X ₂ There is a problem that so-called “Y _2” , which causes deviations in these picture element patterns, that is, picture element displacement occurs and display quality deteriorates.

In view of the above-mentioned conventional problems, the present invention is configured such that display picture elements (dots) corresponding to each other in each liquid crystal panel that is a laminate of projection type color liquid crystal display panels are configured so as to surely overlap each other in projection display. It is an object of the present invention to provide a novel projection type color liquid crystal display panel which prevents misalignment.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention is shown in FIG.
At least two liquid crystal panels 32 and 33 having different display colors are laminated as shown in the principle diagram of FIG. 1, and the transmittance of each of the liquid crystal layers is controlled respectively, and at the same time, the light source 34 on the back side of the first panel collects light. In the liquid crystal display panel 31 for projecting multicolor dot display through the projection lens 36 by the light emitted through the lens 35, the second layer is different from the dot shape 32f and the arrangement interval of the liquid crystal panel 32 of the first layer. LCD panel 3
The dot shape 33f of 3 and its arrangement interval are set to the liquid crystal panel 33
And the projection lens 36 according to the distance.

[Work]

In the projection type color liquid crystal display panel having the two-layer panel structure of the present invention, the bit shape 33f of the second layer liquid crystal panel 33 and the arrangement interval thereof are different from the dot shape 32f of the first layer liquid crystal panel 32 and the arrangement interval thereof. Is reduced in accordance with the distance between the liquid crystal panel 33 and the projection lens 36, so that the dots (picture elements) 32f, 33f corresponding to each other in the liquid crystal panels 32, 33 of the first and second layers are It will surely overlap in projection display. That is, as shown in FIG. 1B, the relationship between the dot shape X ₁ Y ₁ of the first liquid crystal panel 32 and the dot shape X ₂ Y ₂ of the second liquid crystal panel 33, which are arranged at a predetermined interval d, is expressed as X ₁ Y 2. ₁ > X ₂ Y ₂ and the dot shape X ₁ Y ₁ and projection lens
The distance between 36 and the relationship between the distance between the dot-shaped X ₂ Y ₂ and the projection lens 36 is a _{X 1 Y 1 · 0> X} 2 Y 2 · 0, dot shape X of the first liquid crystal panel 32 ₁ Y ₁ and the dot shape X ₂ Y ₂ of the second liquid crystal panel 33 are opposed to each other via the projection lens 36 Screen 37
By superimposing and projecting on the screen 37, the relationship between the projection pattern A of the dot shape X ₁ Y _{1 and} the projection pattern B of the dot shape X ₂ Y ₂ on the screen 37 is X ₁ ′ Y ₁ ′ = X ₂ ′. It becomes Y ₂ , and the pixel shift is prevented.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a cross-sectional view of essential parts showing an embodiment of the projection type color liquid crystal display panel according to the present invention.

In the figure, reference numeral 32 denotes a phase transition between a pair of transparent glass substrates 32a and 32b provided with stripe-shaped transparent electrodes 32c covered with an alignment film 32d on the inner surface, for example, a white transparent state to a red scattering state. A first liquid crystal panel filled with a phase transition type liquid crystal 32e having a display color.
A pair of transparent glass substrates 33 on which stripe-shaped transparent electrodes 33c covered with an alignment film 33d on the inner surface thereof are provided on the same 32
Between the a and 33b, for example, a second liquid crystal panel 33 filled with a phase change type liquid crystal 33e having a display color that changes from a white transparent state to a red scattering state is laminated, and has a two-layer structure. .

Further, the dot arrangement interval determined by the shape of the dots defined by the width of the opposing electrodes and the electrode arrangement pitch of the first liquid crystal panel 32 of the first layer and the second liquid crystal panel 33 of the second layer is the first liquid crystal panel. With respect to the dot shape of 32 and the arrangement interval thereof, the dot shape of the second liquid crystal panel 33 and the arrangement interval thereof are reduced in accordance with the distance to the projection lens 36 of the projection optical system (not shown) combined with the liquid crystal panel 33. It is configured.

That is, the relationship between the dot shapes of the first and second liquid crystal panels 32 and 33 will be described in more detail. For example, as shown in FIG. 3, a dot shape group having a plurality of dot shapes in the first liquid crystal panel 32 of the first layer. A dot shape group having a plurality of dot shapes in the second liquid crystal panel 33 with a length of 32 g being l ₁ .
If the length of 33 g is l ₂ , the distance between the first liquid crystal panel 32 and the projection lens 36 is d, and the distance between the first liquid crystal panel 32 of the first layer and the second liquid crystal panel 33 of the second layer is Δd, The length l ₂ of the dot shape group 33g of the second liquid crystal panel 33 of the second layer is l ₂ = (d−
The structure is reduced to Δd) · l ₁ / d.

Further, assuming that the lateral length of each dot shape 32f of the first liquid crystal panel 32 is S ₁ , each dot shape 33f of the second liquid crystal panel 33 is shown.
The lateral length S _{2 of} is reduced to S ₂ = (d−Δd) · S ₁ / d,
Assuming that the vertical length of each dot shape 32f of the first liquid crystal panel 32 is T ₁ , the vertical length T ₂ of each dot shape 33f of the second liquid crystal panel 33 is T ₂ = (d−Δd) · T since it is reduced to ₁ / d, when the size of each dot shape 32f of the first liquid crystal panel 32 and V _1, the size of each dot shape 33f of the second liquid crystal panel 33 V
₂ is reduced to V ₂ = S ₂ · T ₂ = [(d−Δd) / d] ² · V ₁ .

Furthermore, each dot array pit of the first liquid crystal panel 32 is
When P ₁ is set, the dot arrangement pitch P _{2 of} the second liquid crystal panel 33 is set to P ₂
Is reduced to P ₂ = (d−Δd) · P ₁ / d.

Therefore, since the dot arrangement pitch P ₂ of the second liquid crystal panel 33 is the same pitch over the entire panel surface, the same dot shape and arrangement interval are provided over the second liquid crystal panel 33 of the second layer.

FIG. 4 is a conceptual diagram three-dimensionally showing the dot shapes and arrangement configurations of the first and second liquid crystal panels 32, 33.

This ensures that the dots (picture elements) 32f and 33f corresponding to each other on the first and second liquid crystal panels 32, 33 will overlap in the projection display without fail, resulting in a two-layer panel structure with no picture element displacement. The projection type color liquid crystal display panel 31 can be obtained.

Therefore, such a projection type color liquid crystal display panel 31 of the present invention is attached to the OHP 41 as shown in FIG. 5, and the irradiation light from the light emission source 42 of the OHP 41 is passed through the condenser lens 43 such as a Fresnel lens. The display data is irradiated to the rear surface of the panel, and the display data stored in advance is edited into necessary display data by the personal computer (personal computer) 44 or the disk driver 45 and read out to the control unit 46. This display data signal is converted into a drive voltage necessary for display drive in the panel drive circuit 47 via the control unit 46 and is supplied to the liquid crystal display panel 31, so that a desired voltage formed on the surface of the liquid crystal display panel 31 can be obtained. It is possible to display the color liquid crystal display image clearly and enlarged on the screen 49 through the projection unit 48 composed of a projection lens, a reflecting mirror and the like without any pixel shift.

In the above embodiments, the projection type color liquid crystal display panel has an example of a structure in which two liquid crystal panels having different display colors are laminated, but the present invention is not limited to this example. For example, it can be applied to a structure in which three liquid crystal panels or three or more liquid crystal panels with different color displays are stacked, and the same effect can be obtained.

Also, as a two-layer liquid crystal panel with different display colors,
As shown in FIG. 6, liquid crystal layers 56 and 57 having different display colors are interposed between a rear transparent substrate 51 and a transparent front substrate 52 each having a transparent electrode 54 covered with an alignment film 55 on the inner surface thereof. Then, a structure may be used in which the intermediate substrate 53 having the transparent electrodes 54 covered with the alignment film 5 on both sides is provided.

〔The invention's effect〕

As is apparent from the above description, according to the projection type color liquid crystal display panel of the present invention, when the color liquid crystal display information is projected on the screen and enlarged and displayed in combination with the OHP, it is clear without any pixel shift. You can achieve various color display images,
The display quality can be improved.

[Brief description of drawings]

1 (a) and 1 (b) are principle diagrams for explaining the resolution of picture elements in a projection type color liquid crystal display panel according to the present invention, and FIG. 2 is an embodiment of a projection type color liquid crystal display panel according to the present invention. FIG. 3 is a sectional view for explaining the relationship between the dot shape groups of the first liquid crystal panel and the second liquid crystal panel in the projection type color liquid crystal display panel according to the present invention, and FIG. 4 is the present invention. Of the projection type color liquid crystal display panel according to the present invention, showing three-dimensionally the dot shape and arrangement of the first liquid crystal panel and the second liquid crystal panel, and FIG. 5 is a projection using the projection type color liquid crystal display panel according to the present invention. FIG. 6 is an explanatory view showing an example of an optical system, FIG. 6 is a cross-sectional view of an essential part showing another embodiment of the projection type color liquid crystal display panel according to the present invention, and FIGS. 7 (a) to 7 (c) are phase transition type liquid crystals. Fig. 8 is an explanatory view of the operating principle of the panel, and Fig. 8 is a conventional projection type liquid. 9 is an explanatory view showing an example of a projection optical system using a crystal display panel, and FIGS. 9 (a) and 9 (b) are views for explaining problems of the conventional projection type color liquid crystal display panel. 1 to 6, 31 is a color liquid crystal display panel, 32 is a first liquid crystal panel, 32a,
32b, 33a, 33b are transparent glass substrates, 32c, 33c, 54 are transparent electrodes, 32d, 33d, 55 are alignment films, 32e, 33e, 56, 57 are liquid crystals, 32f, 3
3f, X ₁ Y ₁ , X ₂ Y ₂ is dot shape, 32g, 33g is dot shape group, 3
3 is the second liquid crystal panel, 34 and 42 are light emitting sources, 35 and 43 are condenser lenses, 36 is a projection lens, 41 is OHP, 44 is a personal computer, 45 is a disk driver, 44 is a personal computer, 45 is a disk driver, 46 Is a control circuit, 47 is a drive circuit, 48 is a projection unit, 49 is a screen, 51 is a rear transparent substrate, 52 is a front transparent substrate,
Reference numerals 53 denote intermediate transparent substrates, respectively.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-19924 (JP, A) JP-A-61-198270 (JP, A)

Claims (1)

(57) [Claims] 1. At least two liquid crystal panels (32, 33) having different display colors are laminated, and the transmittance of the liquid crystal layers of each laminated liquid crystal panel (32, In a liquid crystal display panel (31) for projecting multicolor dot display by irradiation light, a liquid crystal panel (33) having a second layer or more with respect to the dot shape (32f) of the first layer liquid crystal panel (32) and the arrangement interval thereof.
A projection type liquid crystal display panel characterized in that the dot shape (33f) and the arrangement interval thereof are sequentially reduced.