JPH0387722A - Back face projection type liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve contrast by providing an optical means for removing scattering light between a transmission-scattering type liquid crystal display element and a screen. CONSTITUTION:The light emitted from a light source 1 transmits the transmission-scattering type liquid crystal display element 2 straightly as it is while the picture elements of the liquid crystal display element 2 is in a transmission state. The light passes through the optical means for removing the scattering light and is projected onto the screen 11 so that the light is eventually visually recognized as a bright display. The light emitted from the light source 1 is scattered by the transmission-scattering type liquid crystal display element 2 while the picture elements of the liquid crystal display element 2 are in the scattering state; therefore, the light is removed by the optical means for removing the scattering light and is the arrival of this light at the screen is substantially prevented. Thus, the bright and high contrast ratio is easily obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rear projection type liquid crystal display device using a transmission-scattering type liquid crystal display element.

[Conventional technology] In recent years, liquid crystal displays have been used in high-density, high-performance applications such as watches, calculators, various home appliances, personal word processors, hand belt computers, pocket TVs, etc. by taking advantage of their low power consumption and low voltage drive characteristics. It is widely used in display devices.

The mainstream of such liquid crystal display elements is one using TN (twisted nematic) type liquid crystal.

Conventionally, TN type liquid crystal display elements have extremely small leakage current and low power consumption, so they are suitable for applications using batteries as a power source, and have been mainly used as reflective types.

However, when used indoors, the power is taken from the AC line, so this advantage of low power consumption is no longer important, and a good-looking display is required.

For this reason, this TN type liquid crystal display element is increasingly being used in combination with a light source as a transmission type liquid crystal display device.

[Problems to be Solved by the Invention] However, since the TN type liquid crystal display element requires two polarizing plates, it has a problem of low light transmittance. In particular, when color display is performed using a color filter, only a few percent of the incident light can be used, requiring a strong light source, which results in increased power consumption and the liquid crystal display element due to heat generation from the light source. This caused the problem of impact on the

On the other hand, a liquid crystal resin composite in which a liquid crystal material is dispersed and held in a resin matrix between the electrode-attached substrates, and the refractive index of the resin matrix is made to almost match the ordinary refractive index (n,) of the liquid crystal material used. A transmission-scattering type liquid crystal element formed by sandwiching a light source has been attracting attention mainly as a light control body for windows and the like. It has also been proposed to use this transmission-scattering liquid crystal element as a display device.

This transmission-scattering type liquid crystal element does not require the use of a polarizing plate, so basically it has the advantage that an extremely bright display can be easily obtained.

However, when viewing this transmissive-scattering liquid crystal element directly from the front with a light source placed on the back side, not only does light pass through the transmissive part, but light also scatters and leaks from the scattering part. It wasn't much of a problem as a light control body, but
As a display device, it has a problem in that it has a poor visual appearance. For this reason, it has been difficult to put it into practical use as a display device that also uses a light source.

It has also been proposed that this transmission-scattering liquid crystal element be used to project images onto a large screen like a normal projection television. However, in this case, the small transmissive-scattering liquid crystal element is magnified more than 10 times for display, which requires a large amount of space, so there is a problem that it can only be used for specific purposes such as televisions. There was a point.

[Means for Solving the Problems] The present invention has been made to solve the above-mentioned problems.A liquid crystal substance is dispersed and held in a resin matrix between electrode-attached substrates, and the refractive index of the resin matrix is A transmission-scattering liquid crystal display element sandwiching a liquid crystal resin composite whose index of refraction (n,) is almost the same as the ordinary refractive index (n) of the liquid crystal material used, a light source disposed on one side of the element, and a light source on the other side. A rear projection type liquid crystal display device comprising a screen disposed on the screen, and an optical means for removing scattered light disposed between the transmission-scattering type liquid crystal display element and the screen, and an optical means for removing the scattered light. The present invention provides a rear projection type liquid crystal display device characterized in that the means comprises a microlens array and a slit.

In the transmission-scattering type liquid crystal display element of the present invention, a liquid crystal resin composite that electrically controls the scattering state and the transmission state is used as the liquid crystal material sandwiched between the pair of electrode-attached substrates. No plate is required, and the transmittance of light during transmission can be greatly improved. Therefore, a bright display is possible, and a bright display with good contrast h can be obtained.

Furthermore, problems such as alignment treatment essential for TN-type liquid crystal display elements, poor alignment due to generated static electricity, and destruction of electrodes and active elements can be avoided, so the manufacturing yield of liquid crystal display elements can be significantly improved.

Furthermore, since this liquid crystal resin composite is in the form of a film after curing, problems such as short circuits between substrates due to pressurization of the substrates and destruction of electrodes, alignment, and active elements due to movement of spacers are less likely to occur.

Furthermore, in the case of an active matrix liquid crystal display element in which each pixel is provided with an active element, the resistivity of this liquid crystal resin composite is equivalent to that of the conventional TN mode, and it is similar to that of the DS (dynamic scattering) mode. It is not necessary to provide a large storage capacitor for each pixel electrode, the active element can be easily designed, and the power consumption of the liquid crystal display element can be kept low. Therefore, production is easy because the alignment film forming process can be removed from the manufacturing process of conventional TN mode liquid crystal display elements.

If necessary, active elements provided in the pixel electrodes include transistors, diodes, nonlinear resistance elements, etc., and two or more active elements may be arranged in one pixel if necessary.

The liquid crystal resin composite is sandwiched between an active matrix substrate provided with such an active element and a pixel electrode connected thereto, and a counter electrode substrate provided with a counter electrode to form a liquid crystal display element.

As the light source, a conventionally known light source can be used. In particular, a surface emitting light source that can uniformly supply light to the surface of the liquid crystal display element is preferable. Furthermore, when using a point light source or a line light source, a diffuser plate, a light guide plate, etc. may be used to ensure that the light is supplied uniformly.

Since the present invention does not project over a long distance, it does not require a large-scale projection light source like that used in ordinary projection televisions, and can be used with the same light source used in conventional ordinary liquid crystal display elements. It is.

The optical means for removing scattered light disposed between the transmissive-scattering liquid crystal display element and the screen includes a screen disposed close to the transmissive-scattering liquid crystal display element on the opposite side from the light source. Any optical means can be used as long as it allows only the light that has passed through the transmission-scattering type liquid crystal display element to reach the device and cuts off the light that has been scattered by the transmission-scattering type liquid crystal display element.

Specifically, there is an optical system consisting of a microlens array and a slit. In this case, only the straight light that has passed through the transmission-scattering type liquid crystal display element is focused by the microlens, and transmitted through a slit placed at the focal point of the microlens.
Light reaches the screen. On the other hand, the light scattered by the scattering part of the transmissive-scattering liquid crystal display element does not travel straight, so even if it is focused by the microlens, it does not pass through the focal point and is blocked by the slit, so it does not reach the screen. do not.

As a result, scattered light is removed and only transmitted light that has traveled straight reaches the screen, resulting in a bright display with good contrast.

This slit may be a plate-shaped one with a small hole at the focal point of the microlens array.

In addition, instead of an optical system consisting of a microlens array and slits, a perforated plate with many fine holes whose length is more than twice the diameter of the hole can be used, but the transmitted light can be fully utilized. Since this is not possible, the display will be dark.

The screen may be placed away from the slit by the same distance as the distance between the microlens array and the slit. Thereby, the image is displayed on the screen in the same size (same size) as the transmission-scattering type liquid crystal display element.

In the present invention, as a liquid crystal display element, a liquid crystal substance is dispersed and held in a resin matrix between substrates with electrodes, and the refractive index of the resin matrix is made to almost match the ordinary refractive index (no) of the liquid crystal used. Since it uses a liquid crystal display element sandwiching a transmission-scattering type liquid crystal resin composite, it is bright and
It has the advantage that a high contrast ratio can be easily obtained.

Specifically, in the present invention, as a liquid crystal display element, a liquid crystal resin composite consisting of a resin matrix in which many fine holes are formed and a liquid crystal material filled in the hole portions is sandwiched between substrates with electrodes, Depending on the voltage applied between the electrodes, the refractive index of the liquid crystal material changes, and the relationship between the refractive index of the resin matrix and the refractive index of the liquid crystal material changes, and when the refractive indexes of the two match, it becomes a transparent state. , a liquid crystal display element can be used that is in a scattering state when the refractive index is different.

A liquid crystal resin composite consisting of a resin matrix with many fine pores and a liquid crystal substance filled in the pores has a structure in which the liquid crystal substance is sealed in liquid bubbles like microcapsules. However, the individual microcapsules do not have to be completely independent, and the individual liquid crystal bubbles may be connected through slits as in a porous body.

The liquid crystal resin composite used in the liquid crystal display element of the present invention is prepared by mixing a liquid crystal substance and a material constituting the resin matrix to form a solution or latex, and then curing this by photocuring, heat curing, or solvent removal. The resin matrix may be separated by curing, reaction curing, etc., and the liquid crystal material may be dispersed in the resin matrix.

It is preferable to use a photocuring or thermosetting resin as the resin used, since it can be cured in a closed system.

In particular, it is preferable to use a photocurable resin because it can be cured in a short time without being affected by heat.

The specific manufacturing method is similar to the conventional manufacturing method for liquid crystal display elements, in which a cell is formed using a sealing material, a mixture of an uncured resin matrix and a liquid crystal substance is injected through an injection port, and a After the entrance is sealed, it can be cured by irradiation with light or by heating.

In addition, in the case of the liquid crystal display element of the present invention, a sealing material is not used (for example, a mixture of an uncured resin matrix and a liquid crystal substance is supplied onto one substrate with electrodes, and then the other substrate with electrodes is attached). The substrates can also be stacked and cured by light irradiation or the like.

Of course, after that, a sealing material may be applied to the periphery to seal the periphery. According to this manufacturing method, the mixture of uncured resin matrix and liquid crystal substance is simply roll-coated and supplied by spin cord, printing, application with a dispenser, etc., so the injection process is simple and productivity is high. Extremely good.

In addition, the mixture of these uncured resin matrices and liquid crystal substances contains spacers such as ceramic particles, plastic particles, and glass fibers for controlling the gap between the substrates, pigments, dyes,
Viscosity modifiers, additives that do not adversely affect the performance of the invention may be added.

During the curing process, this element is cured by applying a sufficiently high voltage only to a specific part, so that part can always be in a light-transmitting state, so if there is something you want to display in a fixed manner, may form such a normally transparent portion.

The response time of a liquid crystal display element using such a liquid crystal resin composite of the present invention is that the rise of voltage application is 3N50ms.
ec, and the fall of voltage removal is about 10 to 80 m5 ec, which is faster than the conventional TN mode liquid crystal display element.

In addition, its voltage-transmittance electro-optical characteristics are different from that of conventional TN.
The mode is relatively gentler than that of a liquid crystal display element, and it is easier to drive for gradation display.

Note that the higher the transmittance of a liquid crystal display element using this liquid crystal resin composite in a transmission state, the better, and the haze value in a scattering state is preferably 80% or more.

In the present invention, under applied voltage, the refractive index of the resin matrix (after curing) is made to match the ordinary refractive index (no) of the liquid crystal material used.

As a result, when the refractive index of the resin matrix and the refractive index of the liquid crystal substance match, light is transmitted, and when they do not match, the light is scattered (cloudy). The scattering properties of this element are higher than those of conventional DS mode liquid crystal display elements, and a display with a high contrast ratio can be obtained.

Refractive index anisotropy Δn of the liquid crystal material used (20.

-n, ) contributes to scattering properties in the absence of an electric field, and in order to obtain high scattering properties, it is preferable that it is larger than a certain level,
Specifically, a preferable condition is Δn>0.18. Further, it is preferable that the ordinary light refractive index n0 of the liquid crystal used is approximately equal to the refractive index n of the resin matrix, and in this case, high transparency can be obtained when an electric field is applied. Specifically, no O-
03<np<n.

It is preferable to satisfy the relationship of +0.05.

In addition, in order to improve the scattering property in the absence of an electric field, it is effective to increase the volume fraction Φ of the operable liquid crystal in the liquid crystal resin composite, and it is preferable that Φ>20%, which has higher scattering property. It is preferable that Φ>35%. On the other hand, if Φ becomes too large, the structural stability of the liquid crystal resin composite deteriorates, so Φ<70% is preferable.

When no electric field is applied, the liquid crystal display element of the present invention exhibits a scattering state (that is, a cloudy state) due to the difference in refractive index between the unaligned liquid crystal material and the resin matrix.

Therefore, when used as a projection display device as in the present invention, light is scattered in the areas without electrodes, and the pixel areas (
Even if there is no light-shielding film on parts other than segment parts),
It appears black because no light reaches the projection screen. This eliminates the need to shield parts other than the pixels with a light-shielding film or the like in order to prevent light leakage from the parts other than the pixels, and there is also the advantage that the step of forming a light-shielding film is not necessary.

An electric field is then applied to the desired pixel. In the pixel area to which this electric field is applied, the liquid crystal is aligned, and the ordinary refractive index of the liquid crystal (
When the refractive index (np) and the refractive index (np) of the resin matrix match, a transmission state is indicated, and light is transmitted through the desired pixel, resulting in a bright display on the projection screen.

By curing this element while applying a sufficiently high voltage only to a specific part during the curing process, that part can always be in a light transmitting state.
If there is something that you want to display in a fixed manner, you may form such a normally transparent part.

Further, the rear projection type liquid crystal display device of the present invention can perform color display by providing a color filter. This color filter may be of a single color or of multiple colors, and in order to achieve high contrast, it is preferable to provide it on the substrate side on the light source side. This color filter may be provided on the inner surface of the substrate, that is, above or below the electrode surface, or may be provided on the outside.

Furthermore, color display may be performed by mixing dyes, pigments, etc. into the liquid crystal resin composite.

Further, the color of the light source may be partially changed, or the color of the light source may be changed depending on the display content.

FIG. 1 is a sectional view of a rear projection type liquid crystal display device of the present invention.

In Figure 1, 1 is a light source, 2 is a liquid crystal display element, 3
．． 4 is a substrate made of glass, plastic, etc.; 5 is an active element such as a transistor, diode, nonlinear resistance element, etc. 6.
7 is ITO (InaOs-SnOi).

5n02 electrode, 8 a liquid crystal resin composite, 9 a microlens array, IO a slit placed at its focal point,
Reference numeral 11 indicates a screen on which an image is projected, and 12 indicates an observer below the screen.

In this liquid crystal display element 2, a liquid crystal substance is dispersed and held in a resin matrix between a substrate 3.4 provided with a pair of electrodes 6.7, and the refractive index of the resin matrix is the ordinary light refraction of the liquid crystal substance used. This is a transmission-scattering type liquid crystal display element in which a liquid crystal resin composite 8 whose ratio (no) is almost the same as that of the liquid crystal resin composite 8 is sandwiched therebetween.

As a result, when the pixels of the transmission-scattering type liquid crystal display element are in the transmission state, the light emitted from the light source 1 passes straight through the liquid crystal display element 2, is focused by the microlens array 9, and is placed at its focal point. It passes through the slit 10 and is projected onto the screen 11 for the viewer 12 at the bottom of the figure.
This will be visually recognized as a bright display. Furthermore, when the pixels of this transmissive-scattering type liquid crystal display element are in a scattering state, the light emitted from the light source 1 is scattered by the liquid crystal display element 2, and is focused by the microlens array 9, but at its focal point. The light is projected onto the screen 11 with almost no light passing through the arranged slits 1O, and is visually recognized by the viewer 12 at the bottom of the figure as a dark display.

It is preferable that the light incident on the liquid crystal display element from this light source be parallel rays. However, since the present invention does not provide enlarged display on a large screen like a normal projection display device,
Since the light is projected with a short optical path, display is possible even if the light beams are not completely parallel.

A slit 10 is placed at each focal point of the microlens array 9. The microlenses of the microlens array 9 are
In the case of dot-shaped pixels as in the above example, one microlens may correspond to one pixel. When a pixel is a long and narrow segment such as a 7-segment mortar-shaped display or a bar graph display, it is preferable that one pixel corresponds to a plurality of microlenses. Furthermore, when the pixels are dot-shaped, a plurality of pixels may correspond to one microlens. For example, when actually expressing one pixel in full color using three pixels of RGBa color, there is virtually no effect even if the image is displayed horizontally or vertically inverted using a microlens. Furthermore, when 16 pixels correspond to one microlens, each 16 pixel group is driven horizontally and vertically inverted so that the observer can see normally during driving. Although it is troublesome, it can be handled.

Although it depends on the size of the display device, the size of pixels, etc., the pitch of the microlenses is approximately 0.1 to 20 mm, and the focal length is approximately 0.1 to 20 mm.

However, if this focal length is too short, it becomes difficult to remove scattered light, so it is preferable to set the focal length to 1 mm or more.

In addition, the diameter of the slit hole should be approximately one-tenth of the size of one microlens, that is, one-tenth of the pitch of the microlens, and the contrast ratio, brightness, and individual It may be determined in consideration of the degree of deviation of the focal length of the microlens, etc.

Moreover, the shape of the microlens may be a spherical lens or an aspherical lens. When detailed display is required, it is preferable to use an aspherical lens because aberrations can be corrected.

The electrodes of the present invention may be patterned so that both electrodes face each other in a pixel. For simple patterns,
Ordinary electrodes may be used, but when displaying a complicated pattern, it is preferable to provide an active element in each pixel since a liquid crystal display element using this liquid crystal resin composite has poor dynamic drive characteristics. When providing an active element, T
When using a 3-terminal element such as a PT (thin film transistor), it is sufficient to provide a solid electrode common to all pixels on the electrode substrate on the opposite side, but when using a 2-terminal element such as an MIM element or PIN diode, multiple It is patterned into a pattern.

Further, when providing an active element and using TPT, silicon is suitable as the semiconductor material, and amorphous silicon, polycrystalline silicon, etc. can be used. In particular, polycrystalline silicon is not as photosensitive as amorphous silicon, so
It is preferable that the light from the light source is not blocked by the light shielding film because malfunction does not occur. When this polycrystalline silicon is used as a projection type liquid crystal display device as in the present invention, a strong projection light source can be used and a bright display can be obtained.

Furthermore, in the case of conventional TN-type liquid crystal display elements, a light-shielding film is often formed between the pixels in order to prevent light leakage from between the pixels, and at the same time, a light-shielding film is also formed on the active element part at the same time. Forming a light shielding film on the active element portion does not significantly affect the overall process. That is, even if polycrystalline silicon is used as the active element and no light shielding film is formed in the active element portion, if it is necessary to form a light shielding film between pixels, the number of steps cannot be reduced.

In contrast, in the present invention, as described above, a liquid crystal resin composite is used in which the refractive index of the resin matrix almost matches the ordinary refractive index (n, H: n, H) of the liquid crystal used. Therefore, in areas where no electric field is applied, light is scattered and becomes black on the projected screen, so there is no need to form a light-shielding film between pixels.For this reason, when polycrystalline silicon is used as an active element, Since it is not necessary to form a light shielding film on the element portion, the step of forming a light shielding film can be eliminated, the number of steps can be reduced, and productivity can be improved.

In addition, the rear projection type liquid crystal display device of the present invention may have an infrared cut filter, an ultraviolet cut filter, etc. laminated thereon, or may have characters, figures, etc. printed thereon, or may use a plurality of liquid crystal display elements. You can do it like this.

In the present invention, when a photocurable resin is used as the uncured resin constituting the liquid crystal resin composite, it is preferable to use a photocurable vinyl resin.

Specifically, photocurable acrylic resins are exemplified, and those containing acrylic oligomers that are polymerized and cured by light irradiation are particularly preferred.

The liquid crystal substance used in the present invention is a liquid crystal substance in which the refractive index of the resin matrix matches the ordinary refractive index (no) of the liquid crystal substance, and may be used alone or in a composition. It can be said that it is more advantageous to use a composition in order to satisfy various required performances such as operating temperature range and operating voltage. Specifically, nematic liquid crystal having positive dielectric anisotropy is used.

In addition, when a photocurable resin is used as the liquid crystal substance used in the liquid crystal resin composite, it is preferable that the photocurable resin is dissolved uniformly, and the cured product after light exposure is not dissolved or dissolved. When using a composition that is considered difficult,
It is desirable that the solubility of each liquid crystal substance be as close as possible.

In the present invention, by using a liquid crystal resin composite, there is a low risk of short-circuiting between the upper and lower transparent electrodes, and there is no need to strictly control the orientation and substrate gap as in a normal TN type display element. A liquid crystal display element whose transmission state and scattering state can be controlled can be manufactured with extremely high productivity.

[Function] In the rear projection type liquid crystal display device of the present invention, when the pixels of the transmission-scattering type liquid crystal display element are in the transmission state, the light emitted from the light source passes straight through the liquid crystal display element as it is, and scattered light is removed. The light passes through an optical means and is projected onto a screen, where it is visually recognized as a bright display. Also, this transmission -
When the pixels of the scattering type liquid crystal display element are in a scattering state, the light emitted from the light source is scattered by the liquid crystal display element, so it is removed by an optical means for removing the scattered light, and almost no light reaches the screen. Therefore, the display will be visually perceived as dark by the observer.

According to the present invention, by using a transmissive-scattering type liquid crystal display element, which was originally capable of displaying only white (scattering part) and transmissive part (transmissive part) with poor visibility, black ( It becomes possible to display the scattered part) and white or color (transparent part).

[Example] Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 Chromium was deposited to a thickness of 60 nm on a glass substrate (Corning Corporation 1147059 substrate) and patterned to form a gate electrode. Subsequently, a silicon oxynitride film and an amorphous silicon film were deposited using a plasma CVD apparatus. This was annealed using a laser and then buttered to form polycrystalline silicon. Phosphorus-doped amorphous silicon and chromium were deposited on this using plasma CVD and a vapor deposition apparatus, respectively, and buttered to cover the polycrystalline silicon to form the first layer of source and drain electrodes.゛Furthermore,
After ITO was deposited, patterning was performed to form a pixel electrode. Subsequently, chromium and aluminum were successively deposited and patterned to connect the pixel electrode and the first layer source electrode and drain electrode to form the second layer source electrode and train electrode. Thereafter, a silicon oxynitride film was again deposited using a plasma CVD apparatus to serve as a protective film, and an active matrix substrate serving as one electrode-attached substrate was created.

The other electrode-attached substrate made of the same glass substrate with solid ITO electrodes formed on its entire surface and the previously manufactured active matrix substrate were arranged so that the electrode surfaces faced each other, and a spacer with a diameter of 11.0 μm was placed inside. After spraying, the surrounding area was sealed with an epoxy sealing material except for the injection port part, and an empty cell with a substrate gap of 11.0 LLm was manufactured.

6 parts of 2-ethylhexyl acrylate and 18 parts of hydroxyethyl acrylate, 14 parts of acrylic oligomer (rM-1200J manufactured by Toagosei Kagaku Co., Ltd.), and 0°4 of Darocure-1,116J manufactured by Merck & Co. as a photocuring initiator. As part and liquid crystal, BD I-1 r E-8J
and 62 parts of were uniformly dissolved.

This mixture was injected from the injection port into the empty cell manufactured by the above method, and the injection port was sealed.

This was irradiated with ultraviolet rays for 30 seconds to cure the liquid crystal resin composite, thereby producing a transmission-scattering type liquid crystal display element.

The produced liquid crystal display element was in a scattering state when no voltage was applied, and was in a transparent state when a voltage was applied.

As shown in FIG. 1, this liquid crystal display element was provided with an EL as a light source on the back side, and a microlens array and slits as optical means for removing scattered light on the front side. The pitch of the microlenses in the microlens array is 3+nm.
The radius of curvature of the lens was 3 mm, the focal length was 3 mm, and the diameter of the slit hole was 0.1 mm. Note that the pitch of pixels on the active matrix substrate was also set to 3non.

As a result, almost only the light traveling straight from the liquid crystal display element could be transmitted, and almost all the scattered light could be eliminated. The screen was fixed at a position 3 mm apart from this slit.

When the displayed image was viewed from the opposite side of the screen, a displayed image with a contrast ratio of white against a black background of 70 or more was obtained. The drive voltage was AC5V.

Example 2 A rear projection type liquid crystal display device was produced in the same manner as in Example 1 except that the pitch of the pixels of the active matrix substrate in Example 1 was changed to 1 mm.

In this case, since one microlens corresponds to nine pixels, there is no need to drive the nine pixels as one pixel group and drive each pixel group upside down and horizontally inverted. However, the same display as in Example 1 was possible.

Example 3 The pitch of the microlens array of Example 1 was set to 1 mm, and the slits corresponding to this were also used.
A rear projection type liquid crystal display device was produced in the same manner as in Example 1.

In this case, nine microphone 0 lenses correspond to one pixel, and since the diameter of the slit hole was 0.1 mm, the total area of the hole is 9 times that of Example 1. The same display as in Example 1 was possible, except that the display contrast was slightly lower than in Example 1 due to the increased amount of scattered light passing through. In order to prevent this decrease in contrast ratio, the diameter of the slit may be made smaller. However, if it is made too small, the slit will not correspond well to the focal point of the microlens due to the precision of the microlens and the precision of the slit, which tends to cause problems such as the display becoming dark and the contrast ratio decreasing. Preferably, it is determined experimentally.

Example 4 Instead of the active matrix substrate of Example 1, a substrate with electrodes was prepared by patterning a 7-segment Japanese character pattern with ITO.

In addition, another substrate with electrodes was prepared by patterning ITO in the same manner so as to correspond to this pattern.

By combining these, a liquid crystal display element was produced in the same manner as in Example 1.

A rear projection type liquid crystal display device was produced in the same manner as in Example 1 except that a cold cathode discharge tube was used as a light source and a green color filter was attached to the light source side of the back substrate.

This rear projection type liquid crystal display device was able to display bright green numbers on a black background.

[Effects of the Invention] In the rear projection type liquid crystal display device of the present invention, a liquid crystal display sandwiching a liquid crystal resin composite whose scattering state and transmission state are electrically controlled is used as a liquid crystal feed sandwiched between substrates with electrodes. Since the device uses a polarizer, there is no need for a polarizing plate, and the transmittance of light during transmission can be greatly improved, resulting in a bright display with a high contrast ratio.

A transmissive-scattering type liquid crystal display element in which a liquid crystal resin composite is sandwiched is unsuitable for transmissive display because the scattering part is white and light passes through the transmissive part. By adopting this configuration, the scattering portion is displayed in black and the transmitting portion is displayed in white or a specific color, thereby providing an easy-to-read transmissive display device similar to a conventional liquid crystal display device. That is, by using a transmission-scattering type liquid crystal display element, it is possible to display black with a backlight display.

Since the rear projection type liquid crystal display device of the present invention uses only a thin optical system, it does not require a long optical path unlike a general projection type liquid crystal display device, and the rear projection type liquid crystal display device is compact and usually only a few centimeters thick. A display device can be obtained.

Furthermore, problems such as alignment treatment such as rubbing, which is essential for TN-type liquid crystal display elements, and destruction of active elements due to generation of static electricity associated therewith can be avoided, so that the manufacturing yield of liquid crystal display elements can be significantly improved.

Furthermore, since this liquid crystal resin composite is in the form of a film after curing, problems such as short circuits between substrates due to pressurization of the substrates and destruction of active elements due to movement of spacers are less likely to occur.

In addition, the specific resistance of this liquid crystal resin composite is the same as that of the conventional TN mode, and there is no need to provide a large storage capacitance for each pixel electrode as in the conventional DS mode, making it easy to design active elements. Therefore, it is possible to easily increase the ratio of the effective pixel electrode area and to keep the power consumption of the liquid crystal display element low.

Furthermore, production is easy because it can be manufactured by simply removing the alignment film forming process from the manufacturing process of conventional TN mode liquid crystal display elements.

Furthermore, a liquid crystal display element using this liquid crystal resin composite has a short response time, and can easily display moving images. Furthermore, since the electro-optical characteristics (voltage-transmittance) of this liquid crystal display element are relatively smooth compared to those of a TN mode liquid crystal display element, it can be easily applied to gradation display.

In addition, in the liquid crystal display element of the present invention, since light is scattered in parts where no electric field is applied, there is no leakage of light during projection even if parts other than pixels are not shielded by a light shielding film, and the gap between adjacent pixels can be reduced. No need to block light. For this reason, in particular, by using an active element made of polycrystalline silicon as an active element, a high-brightness projection light source can be used without a light-shielding film on the active element part, and a high-brightness projection-type liquid crystal display device can be easily manufactured. Obtainable. Furthermore, in this case, there is no need to provide a light shielding film at all, which further simplifies the production process.

In addition to this, the present invention can be applied in various other ways as long as the effects of the present invention are not impaired.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a basic example of a rear projection type liquid crystal display device of the present invention. Light source Liquid crystal display element substrate Active element Electrode Liquid crystal resin composite Microlens array Slit screen Observer = 1 = 2 = 3, : 5 : 6, : 8 : 9 =lO :ll :12 Figure 1 V~12: Time boar Procedural amendment July 3, 1990

Claims (2)

[Claims] (1) A liquid crystal resin composite in which a liquid crystal substance is dispersed and held in a resin matrix between electrode-attached substrates, and the refractive index of the resin matrix is made to almost match the ordinary refractive index (n_o) of the liquid crystal substance used. A transmission-scattering type liquid crystal display element sandwiching a light source, a light source placed on one side of the light source, a screen placed on the opposite side, and a light source placed between the transmission-scattering type liquid crystal display element and the screen. A rear projection type liquid crystal display device comprising an optical means for removing scattered light. (2) A rear projection type liquid crystal display device, wherein the optical means for removing scattered light according to claim 1 comprises a microlens array and a slit.