JPH1091075A - Color display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce power consumption and to enhance the efficiency of light utilization by enlarging extracted monochromatic light so as to visually recognize wide angle of visibility by a slit for selecting and extracting light which makes only light having nearly single wavelength pass through among spectra having respective wavelength. SOLUTION: The light which is transmitted through a prism 3 so as to be spectrally split and so as to have a specified wavelength goes toward the slit 4, and the light having a wavelength component reaching a slit gap part 4a is emitted outside the slit. When the width of the part 4a is set to width by which only light having nearly a single color component passes through, only certain light passing through the part 4a having the single color component can be transmitted through the part 4a. This monochromatic light is enlarged by the micro lens 5a of a convex lens 5. Thus, the monochromatic light is displayed with respect to the large visual field, so that a pixel can be displayed. That is, the dependency of the angle of visibility of the wavelength is compensated by utilizing the lens 5, so that the same picture can be obtained with respect to the wide angle of visibility.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color display device, and more particularly to a display device which improves light use efficiency and lowers power consumption as compared with a conventional color liquid crystal display device.

[0002]

2. Description of the Related Art A portable information device with a display device typified by a PDA, a handy video camera or the like mainly employs a power supply system using a power source as a battery in order to secure portability. is there. Since the capacity of the built-in battery is limited, it is necessary to reduce power consumption and use the battery for a long time. for that reason,
A liquid crystal display is used as a display device of a portable information device. However, in recent years, since a demand for displaying a color image is high, a color liquid crystal display is mounted so that a color image can be displayed. The color liquid crystal display often employs a transmissive liquid crystal display that incorporates a light source and is illuminated from the back from the point of viewability of the user, such as making the screen visible even in a dark place.

However, in the conventional transmission type liquid crystal display, a fluorescent lamp having a large power consumption is used as a backlight which is a light source for illuminating the liquid crystal display panel from the back thereof. It is impossible to drive a portable information device for a long time by a method of increasing the brightness by illuminating with a fluorescent lamp having a large size.

Therefore, it is conceivable to turn off the backlight so that the screen can be viewed. However, in a transmissive liquid crystal display, if the luminance is not improved by the backlight, it may play a role as a display device. Light utilization efficiency is so poor that it is impossible to save power by actually turning on and off the backlight according to the situation.

As described above, a liquid crystal display with low power consumption and high light use efficiency is expected to be used as a display device mounted on a portable information device. However, at present, it is technically impossible to realize a transmissive liquid crystal display. It is.

This is because the transmission type liquid crystal display has the following structure. That is, as shown in FIG. 11, a transmissive liquid crystal display generally includes an array substrate 21, a TFT (thin film transistor) 22, a liquid crystal 23, a backlight 24, a pixel electrode 25, a polarizing plate 26, a color filter 27, and a counter substrate 28. It is composed of

The array substrate 21 is formed by arranging pixel electrodes 25 and TFTs 22 in a matrix on a transparent glass substrate. The pixel electrodes 25 are arranged in units of one pixel, and the array substrate 21 is formed by arranging nxm pixels in a matrix to enable display of a two-dimensional screen.

The counter substrate 28 is in the form of a transparent plate.
A transparent counter electrode is formed on almost one side of the surface. Then, a color filter 27 of a color for obtaining a color component at the pixel is formed on the counter substrate 28 corresponding to the pixel, and a polarizing plate 26 is further formed thereon.

The liquid crystal 23 is composed of an array substrate 21 and a counter substrate 2.
8 are arranged opposite to each other with a predetermined gap therebetween, so that the obtained space is filled. The backlight 24 is a white fluorescent lamp arranged on the back side of the array substrate 21 and illuminating the array substrate 21 from the back side.

Between the counter electrode provided on the counter substrate 28 and the pixel electrode 25 of the array substrate 21, a T
By driving and controlling the FT 22, the applied voltage is controlled to control the electric field intensity, the orientation of the liquid crystal is controlled to adjust the light transmission amount corresponding to the image signal, and an image is displayed.

The light from the backlight 24 passes through the array substrate 21, passes through each pixel electrode 25, and the amount of transmitted light is controlled by the liquid crystal between the counter electrode and each pixel electrode 25 on the array substrate 21. The light is polarized by the polarizing plate 26 and further passes through the color filter 27 and is caught by the user.

As described above, the light from the backlight 24 passes through the polarizing plate 26 and is further used through the color filter 27. By passing through these, the transmission amount is greatly reduced, and the light use efficiency is reduced. Deteriorate. For example, considering the polarizing plate 26, the polarizing plate 26 has a transmittance of about 40%. Therefore, only by transmitting the light through the polarizing plate 26, the light use efficiency is reduced by about 60%. Further, since the color filter 27 is an absorption type, the amount of transmitted light can be reduced to １ ／ only by passing through the color filter 27.

That is, in a color liquid crystal display, a color filter is used for a color display.
The pixels correspond to any of R (red), G (green), and B (blue), and each of the R, G, and B pixels absorbs light other than the transmission wavelength in each pixel. For this reason, the absorption type color filter 2 corresponding to its own color component
7 is arranged. The color filter 27 transmits only 1/3 of the light incident on the filter. That is, among the three primary color components of R, G, and B contained in the white light,
Only the display color component is transmitted corresponding to the display color of the own pixel, and the light of the other two primary color components is absorbed, so that the light use efficiency is reduced to ３. Further, in this conventional display device, as shown in a top view in FIG. 12, a TFT used for driving is formed in a pixel, so that the aperture ratio is limited to about 70%.

[0014]

As described above, in a transmissive color liquid crystal display, it is necessary to illuminate with a backlight from the back, and when it is used as a display of a portable device, the consumption of battery power is a problem. Becomes

To solve this problem, it is conceivable to turn off the backlight so that the screen can be viewed. However, in the case of a transmissive liquid crystal display, if the luminance is not improved by the backlight, it can function as a display device. Light utilization efficiency is so poor that it is impossible to save power by actually turning on and off the backlight according to the situation.

The efficiency of light utilization depends on the aperture ratio of the liquid crystal cell. Therefore, if the aperture ratio of the liquid crystal cell portion is improved, a backlight with low luminance and low power consumption is sufficient, and if the surroundings are bright, the screen can be sufficiently observed even when the backlight is turned off. There is a high possibility that a liquid crystal display that can withstand practical use can be obtained. But,
It is difficult to improve the aperture ratio.

This is because of the structural limitations of the conventional transmission type color liquid crystal display. That is, in the case of the conventional structure, light from the backlight is used through the color filter and the polarizing plate. However, the polarizing plate has a light transmittance of about 40%, which significantly reduces the light use efficiency. The color filters used in the color liquid crystal display are of the absorption type, R (red),
Each pixel of G (green) and B (blue) absorbs light other than the transmission wavelength in each pixel, that is, R
For a component pixel, absorb the wavelengths of the G and B components, for a G component pixel, absorb the wavelengths of the R and B components, and for a B component pixel, absorb the wavelengths of the R and G components. Therefore, only one third of the incident light is used.

In the conventional type, since a TFT used for driving a liquid crystal cell as a pixel display element is formed in a pixel, an aperture ratio is limited to about 70%. Therefore, the only way to increase the luminance and ensure visibility is to use a high-luminance backlight, and there is no way to save power, and this has been a technical limit of the transmissive color liquid crystal display device. Therefore, development of a color display with low power consumption and high light use efficiency is expected.

Therefore, an object of the present invention is as follows.
It is an object of the present invention to provide a color display device having low power consumption and high light use efficiency as a display device mounted on a portable information device.

[0020]

To achieve the above object, the present invention is configured as follows. That is, the present invention firstly provides a light source, a parallel light converting means for converting the output light of the light source into parallel light, a spectral means for splitting the converted parallel light, and the light source from the light source. An incident angle varying means for changing an incident angle to the spectroscopic means, and provided for each pixel,
Of the light of each wavelength separated by the spectroscopic means, a slit for selectively extracting light that passes only light of substantially a single wavelength, and a single wavelength light provided by the pixel and extracted by the slit And a means for enlarging a wide viewing angle.

The color display device having such a configuration is a light-dispersion type color display device. After the output light of the light source is converted into parallel light by the parallel light conversion means, the converted parallel light is transmitted to the light separation means. Inject and split. Then, when the parallel light is made incident on the spectroscopic unit to be split, the deflection angle of the light with respect to the spectroscopic unit is changed by the incident angle changing unit, thereby changing the emission position of the light of a specific wavelength entering the slit, and thereby obtaining the required monochromatic light. The light is extracted and used for color display of pixels.

In the present invention, light of a required wavelength is obtained by spectral separation and slits for color display and used for pixel display. Therefore, in principle, the color display does not require pixels for the three primary colors of RGB that are originally required, and one pixel of a color image can be displayed by a single pixel.

Therefore, a display device with high definition and high light use efficiency can be realized. Also, when forming a full-color display device, a polarizing plate,
By not using a color filter, a display device with higher light use efficiency can be realized. In addition, since the light use efficiency is high, a light-spectral color display device with high luminance can be obtained with a light source having lower power consumption than power consumed by the backlight.

In the present invention, light of a single color (or substantially single color) component passing through the slit is enlarged and displayed for each pixel by an enlargement means provided for each pixel. This allows
Monochromatic light (or substantially single color) is displayed in a wide field of view, and pixel display can be performed. That is,
The same image can be obtained for a wide viewing angle by compensating for the viewing angle dependence of the wavelength.

Secondly, the present invention provides a flat plate which is formed by laminating thin films having different refractive indices in multiple layers, and which causes incident light to be reflected by causing optical interference, and which is reflected and interfered by the flat plate. A slit for selectively extracting light that transmits only light having substantially a single wavelength, and a unit for changing an incident angle of the light reflected by the interference to the slit. I do.

The color display device having such a configuration is a light interference type color display device, in which light is caused to interfere with a flat plate and reflected by wavelength, and among the reflected light,
Only a single wavelength of light is selectively obtained by the slit. Then, by changing the incident angle of the light reflected by the interference to the slit, light having a desired wavelength is extracted and used for color display of pixels.

In the present invention, light of a required wavelength is obtained by light interference and slits for color display, and is used for pixel display. Therefore, in principle, the color display does not require pixels for the three primary colors of RGB that are originally required, and one pixel of a color image can be displayed by a single pixel.

Therefore, a display device with high definition and high light use efficiency can be realized. Also, when forming a full-color display device, a polarizing plate,
By not using a color filter, a display device with higher light use efficiency can be realized. In addition, since the light use efficiency is high, a light interference type color display device having high luminance with a light source having lower power consumption than power consumed by the backlight can be obtained.

The third aspect of the present invention is that a thin plate having a plurality of thin films having different refractive indices is laminated, and a flat plate that reflects the incident light by causing optical interference, and an angle of the light incident on the flat plate. And means for changing.

According to such a configuration, an image is displayed by causing the incident light to be reflected by the flat plate to cause light interference. Then, when displaying an image, the angle of light incident on the flat plate is changed to correspond to the display color.

The color display device having such a configuration is a color display device of the light interference reflection type, and does not include a light source. Therefore, it is possible to greatly reduce power consumption and to increase the aperture ratio. It is possible to obtain a color display device with extremely high use efficiency.

As described above, according to each of the present inventions described above,
It is possible to provide a color display device having higher light use efficiency, higher definition, higher aperture ratio, and lower power consumption as compared with a display device such as a conventional transmissive liquid crystal display.

[0033]

Embodiments of the present invention will be described below with reference to the drawings. In the present invention, three types of color display devices, a light spectral type color display device, a light interference type color display device, and a light interference reflection type color display device will be described. The light spectral type color display device and the light interference type color display device have a built-in light source, and the light interference reflection type color display device does not have a light source, and performs color display by light interference using external light.

[Light Spectral Color Display Device] (First Specific Example) FIG. 1 is a sectional view showing an outline of a light spectral color display device according to a first specific example of the present invention. FIG. 2 is a schematic diagram of one pixel according to the first embodiment of the present invention.

The present invention provides a color display having a new structure that does not require such a color filter and a polarizing plate at all, unlike a liquid crystal display that requires a color filter and a polarizing plate as essential components that significantly reduce light use efficiency. As shown in FIG. 1, the optical spectral color display device of the present embodiment includes a light source 1, a collimator lens 2, a prism 3, a slit 4, and a convex lens 5.

The prism 3 is a micro-prism array in which a plurality of micro-prisms 3a, which are fine prisms, are arranged two-dimensionally, and the micro-prism 3a portion is arranged for each pixel.

The light sources 1 are arranged corresponding to the respective microprisms 3a, and are respectively white light sources. For example, as the light source 1, a cold cathode fluorescent tube, a lamp such as a white light bulb, a surface light source, or the like, which is widely used as a light source of a liquid crystal display panel, can be used.
If three primary colors of (red), G (green) and B (blue) are obtained, LE
A semiconductor light-emitting element such as D (light-emitting diode) or a laser diode may be used and used as a white light source by mixing these three primary colors. When the light source 1 is a point light source, the light source 1 is provided for each pixel. In the case of a surface light source or a line light source, the light source 1 is provided to extend over a plurality of pixels.

The collimator lens 2 is disposed in correspondence with each microprism 3a of the prism 3, and collimates white light from the light source 1 disposed corresponding to the microprism 3a to form a micro-beam. The light is guided to the prism 3a. The side of the prism 3 where the collimator lens 2 is disposed is the incident surface side of the light from the light source 1, and the upper side where the lens is not disposed is the light exit surface.

In this specific example, each collimator lens 2 has a support and drive structure capable of varying the angle with respect to its optical axis by electrical and mechanical control. The angle (deflection angle) of light incident on the prism 3 from the light source 1 can be arbitrarily changed.

The slit 4 is a plate disposed on the light emitting surface side of the prism 3, and a slit gap 4a is formed corresponding to each microprism 3a. The convex lens 5 is an array of lenses in which micro lens groups are densely arranged, and is provided so that the micro lens 5a is arranged for each pixel. Each micro lens 5a of the convex lens 5
Is for enlarging the monochromatic light transmitted through the slit gap portion 4a of the corresponding pixel, and for enlarging and displaying the pixel.

In such a configuration, the white light emitted from each light source 1 corresponding to each pixel is transmitted through the collimator lens 2 corresponding to each pixel and converted into parallel light. The angle of the collimator lens 2 can be changed by electrical and mechanical control. By performing this rotation operation, the angle (deflection angle) of light incident on the prism 3 from the light source 1 can be arbitrarily changed. Is possible. The prism 3 used here has a characteristic that the light is dispersed and the wavelength λ changes as the deflection angle θ changes as shown in the following equation.

Dθ / dλ = (dθ / dn) · (dn / dλ) Here, dn / dλ indicates a dispersion ratio, and n indicates a refractive index of the prism 3. By controlling the incident angle, that is, the declination θ, a specific wavelength of the light transmitted through the prism 3 and dispersed is transmitted through a specific position on the prism 3.
Further, the light of the wavelength transmitted through the specific position is directed to the slit 4, and the light of the wavelength component reaching the slit gap 4a is emitted to the outside of the slit. If the width of the slit gap 4a is set to a width that allows substantially only a single color component to pass, only light of a certain single color component passing therethrough is transmitted from the slit gap 4a. Will be done.

The monochromatic light is enlarged by the micro lens 5a of the convex lens 5. This makes it possible to display monochromatic light in a wide field of view and perform pixel display. That is, the use of the convex lens 5 makes it possible to supplement the viewing angle dependency of the wavelength, and to obtain the same image for a wide viewing angle.

In the case of forming a display device for a display image based on seven colors by the configuration shown in this specific example,
By controlling the declination θ of the collimator lens 2 so that seven colors can be displayed, the number of pixels can be reduced to one-third of that of the conventional method in which a color screen is composed of pixels of three colors of RGB. The display screen can be configured. That is, in the present invention, in order to obtain light of a required wavelength by spectral separation and slits for color display and to provide the light for pixel display, in color display, pixels for the three primary colors of RGB that are originally required are required in principle. Therefore, one pixel of a color image can be displayed by a single pixel.

Therefore, a display device having high definition and high light use efficiency can be realized. Also, when forming a full-color display device, a polarizing plate,
By not using a color filter, a display device with higher light use efficiency can be realized. In addition, since the light use efficiency is high, a light-spectral color display device with high luminance can be obtained with a light source having lower power consumption than power consumed by the backlight.

As described above, according to this example, a power-saving and high-luminance color display device can be obtained. In the above, the deflection angle of the light with respect to the prism is changed by changing the angle of the collimator lens, thereby changing the emission position of the light of the specific wavelength with respect to the slit, extracting the required monochromatic light and providing the color display of the pixel. . Such extraction of light of a specific wavelength can be realized even if the angle of the collimator lens is not variable. An example will be described below.

(Second Specific Example) The second specific example is a light-spectral-type color display device in which the deflection angle of light with respect to the prism is controlled by changing the angle of the prism itself. The cross-sectional view of the light spectral color display device according to the second embodiment is the same as that of the first embodiment shown in FIG.

FIG. 3 is a sectional view showing an outline of an optical spectral type color display device according to a second embodiment of the present invention. As shown in FIG. 3, the light-spectral color display device of this example includes a light source 1, a collimator lens 2, a prism 3, a slit 4, and a convex lens 5. In this specific example, the prism 3 is configured to be supported by a supporting / driving structure capable of changing its angle. That is, in the first specific example, the collimator lens 2 is supported by the supporting / driving structure capable of adjusting the angle, and the angle can be adjusted.
Is fixed at a fixed position, and instead, each microprism 3a of the prism 3 is configured to be adjustable in angle.
Therefore, the prism 3 is a microprism array in the first specific example, whereas each microprism 3
a is independent of each other.

In such a configuration, light emitted from the light source 1 passes through the collimator lens 2 and is converted into parallel light. This parallel light is incident on the prism 3 having a support structure whose angle can be changed by electric and mechanical control. Since each microprism 3a of the prism 3 is configured to be adjustable to an arbitrary angle, the micro prism 3a is transmitted through the prism 3 similarly to the relationship between the declination θ and the wavelength λ described in the first specific example. Each of the split light has a specific wavelength component,
The light passes through a specific position on each microprism 3a in the prism 3.

The light of each wavelength transmitted through each microprism 3a of the prism 3 is transmitted to the slit gap portion 4a of the slit 4 because the slit 4 is provided on the emission side of the light. Only the constituents can pass here.

Therefore, when only a specific monochromatic light is transmitted by using the slit gap portion 4a and the monochromatic light is enlarged by the convex lens 5, the monochromatic light can be displayed in a wide field of view and the pixels can be displayed. become able to.

In the case of forming a display device for a display image based on seven colors by the configuration shown in this specific example,
If the angle of the prism with respect to the light source is varied and the deflection angle θ of the light from the light source with respect to the prism is controlled so that seven colors can be displayed, a conventional method of forming a color screen with pixels of three colors of RGB. , A seven-color display screen can be configured with one third of the number of pixels. That is, in the present invention, in order to obtain light of a required wavelength by spectral separation and slits for color display and to provide the light for pixel display, in color display, pixels for the three primary colors of RGB that are originally required are required in principle. Therefore, one pixel of a color image can be displayed by a single pixel.

Therefore, a display device with high definition and high light use efficiency can be realized. Also, when forming a full-color display device, a polarizing plate,
By not using a color filter, a display device with higher light use efficiency can be realized. In addition, since the light use efficiency is high, a light-spectral color display device with high luminance can be obtained with a light source having lower power consumption than power consumed by the backlight.

As described above, according to this example, a power-saving and high-luminance color display device can be obtained. In the above description, the deflection angle of light with respect to the prism is changed by changing the angle of the prism itself, thereby changing the emission position of light of a specific wavelength with respect to the slit, extracting required monochromatic light, and providing the color display of pixels. . Such extraction of light of a specific wavelength can be realized even if the angle of the prism is not variable.
An example will be described below.

(Third Specific Example) A third specific example is an optical spectrometer having a configuration in which a slit is movable and light of a desired wavelength component is selectively extracted from light split by a prism. It is a type color display device.

The sectional view of the color display device according to the third embodiment is basically the same as that of the first embodiment shown in FIG. FIG. 4 is a cross-sectional view showing an outline of an optical spectral color display device according to a third specific example of the present invention. As shown in FIG. 4, the color display device of this specific example includes a light source 1, a collimator lens 2, a prism 3, a slit 4, and a convex lens 5. In the light spectral color display device of this example, the position of the slit 4 is adjustable. That is, in the first and second embodiments, the collimator lens 2 or the prism 3 is configured to be rotatable, whereas in this embodiment, the collimator lens 2 or the prism 3 has a fixed position fixed structure. The configuration is such that the position 4 can be moved so that it can slide on the prism 3 arrangement surface.

In such a configuration, the light emitted from each light source 1 in each pixel passes through the collimator lens 2 corresponding to each pixel and is converted into parallel light. The parallel light is a micro prism 3 corresponding to each pixel of the prism 3.
The light enters the part a and is separated. With respect to the wavelength of the split light, light of a specific wavelength is transmitted at a specific position on each microprism 3 a in the prism 3.

In order to extract light of an arbitrary wavelength from the light of the wavelength transmitted through the specific position, in the present embodiment, the slit 4 is configured so that the position is moved electrically and mechanically. Therefore, by moving and adjusting the slit 4 and changing the position of the slit gap 4a with respect to the prism 3, light of an arbitrary wavelength can be transmitted from the slit gap 4a. This monochromatic light is enlarged by the convex lens 5. This makes it possible to display monochromatic light in a wide field of view and perform pixel display.

Also in this embodiment, as in the first and second embodiments, a power-saving and high-brightness color display device can be obtained. The above are all examples of the optical spectral color display device. However, color display can be performed not only by a method of dispersing light but also by light interference. Therefore, an example of an optical interference type color display device will be described next.

[Light Interference Color Display Device] (Fourth Specific Example) FIG. 5 is a sectional view showing an outline of a light interference color display device according to fourth to sixth specific examples of the present invention.

A light interference type color display device according to a fourth embodiment of the present invention uses a thin film laminated interference plate which is a multilayer thin film plate to reflect light and extract light of a specific wavelength to be used for display. It is characterized by. As described above, in the fourth specific example, the light source 1 and the collimator lens 2 are used as shown in FIG.
, Thin film laminated interference plate 6, slit 4 and convex lens 5
It is composed of

The color display device of this embodiment using the thin-film laminated interference plate 6 utilizes the following optical properties of a multilayer thin film. That is, the wavelength λ of the light reflected from the thin film
Represents the incident angle of light on the thin film as φ, the refractive index of the thin film as n, the thickness as d, and the phase difference between the incident angle and the reflected angle of light with respect to the thin film as δ.
Then, there is a relationship of λ = 2πn _{j dj} cos φ _j / δ _j (where j is the value of the j-th film). This means that the wavelength of the reflected light changes as the incident angle of the light on the thin film laminated interference plate 6 changes. The color display device of this embodiment utilizes the optical properties of such a multilayer thin film.

In the color display device according to the fourth embodiment, the prism 3 used in the first to third embodiments is abolished, and as shown in FIG. The configuration is such that the thin-film laminated interference plates 6 are arranged at the positions where they were arranged. The thin-film laminated interference plate 6 is fixed at a fixed position, and the collimator lens 2 has a variable angle configuration. By changing the angle of the collimator lens 2, the angle of light incident on the thin-film laminated interference plate 6 can be varied. It has a configuration.

The light sources 1 are arranged corresponding to the respective thin-film laminated interference plates 6 and are white light sources, respectively. For example, this light source 1
For example, a cold cathode fluorescent tube, a lamp such as a white light bulb, a surface light source, and the like, which are widely used as a light source of a liquid crystal display panel, can be used.
If three primary colors (green) and B (blue) are obtained, a semiconductor light emitting element such as an LED (light emitting diode) or a laser diode can be used. When the light source 1 is a point light source, the light source 1 is provided for each pixel. In the case of a surface light source or a line light source, the light source 1 is provided to extend over a plurality of pixels.

The collimator lens 2 includes a thin film laminated interference plate 6
And collimates white light from the light source 1 disposed corresponding to the thin-film laminated interference plate 6 and guides the collimated white light to the thin-film laminated interference plate 6.
The light source 1 is located on the side of the thin film laminated interference plate 6 where the collimator lens 2 is disposed.
From the light incident surface side.

In this embodiment, each collimator lens 2 has a supporting / driving structure whose angle can be varied by electric and mechanical control. Light thin film laminated interference plate 6
Is made variable.

The slit 4 is a plate disposed on the light emission side of the thin film laminated interference plate 6, and a slit gap 4 a is formed corresponding to each thin film laminated interference plate 6. The convex lens 5 is an array of lenses in which micro lens groups are densely arranged, and is provided so that the micro lens 5a is arranged for each pixel. Each micro lens 5a of the convex lens 5
Is for enlarging the monochromatic light transmitted through the slit gap portion 4a of the corresponding pixel, and for enlarging and displaying the pixel.

In such a configuration, the light emitted from the light source 1 passes through the collimator lens 2 whose angle can be varied by electric and mechanical control, and is converted into parallel light. By changing the angle of the collimator lens 2, parallel light can be made incident on the thin-film laminated interference plate 6 at an arbitrary incident angle. The thin-film laminated interference plate 6 on which the parallel light is incident reflects the incident parallel light according to the incident angle. At this time, the thin film laminated interference plate 6 reflects light of a specific wavelength in a specific reflection direction. The light of the wavelength reflected in this specific direction goes to the slit 4 and the slit gap 4a
Is emitted to the outside of the slit. Then, light of a certain single color component that has passed through the slit gap 4a is incident on the microlens 5a of the convex lens 5.

The micro lens 5a enlarges the incident light. This makes it possible to display monochromatic light in a wide field of view and perform pixel display. That is, the use of the convex lens 5 makes it possible to supplement the viewing angle dependency of the wavelength, and to obtain the same image for a wide viewing angle.

In the case of forming a display device for a display image based on seven colors by the configuration shown in this specific example,
By controlling the declination θ of the collimator lens 2 so that seven colors can be displayed, the number of pixels can be reduced to one-third of that of the conventional method in which a color screen is composed of pixels of three colors of RGB. The display screen can be configured. That is, in the present invention, light of a required wavelength is obtained by light interference and a slit during color display and is used for pixel display. Therefore, in color display, each pixel for the three primary colors of RGB which is originally required is required in principle. And one pixel of a color image can be displayed by a single pixel.

Therefore, a display device with high definition and high light use efficiency can be realized. Also, when forming a full-color display device, a polarizing plate,
By not using a color filter, a display device with higher light use efficiency can be realized. In addition, since the light use efficiency is high, a light interference type color display device having high luminance with a light source having lower power consumption than power consumed by the backlight can be obtained.

As described above, according to this example, a power-saving and high-brightness color display device can be obtained. In the above, light of a specific wavelength is emitted in a specific direction by reflecting light with a thin-film laminated interference plate, and this is observed through a slit so that color display is performed. The angle of light incident on the laminated interference plate is changed by changing the angle of a collimator lens. However, in order to change the angle of light incident on the thin-film laminated interference plate, the angle can be changed by changing the angle of the collimator lens, or by changing the angle of the thin-film laminated interference plate itself. The method will be described below.

(Fifth Specific Example) FIG. 7 is a sectional view showing an outline of an optical interference type color display device according to a fifth specific example of the present invention. The light interference type color display device of the present embodiment is shown in FIG.
As shown in the figure, the light source 1, the collimator lens 2, the thin-film laminated interference plate 6, the slit 4, and the convex lens 5 are provided, and the collimator lens 2 is made variable in angle in the fourth specific example. In this specific example, the angle of the thin film laminated interference plate 6 is made variable so that the angle with respect to the incident light can be adjusted. Therefore, the collimator lens 2 is fixed at a fixed position.

In the present apparatus, as shown in FIG. 7, the collimator lens 2 is arranged corresponding to the thin-film laminated interference plate 6, and the light source 1 arranged corresponding to the thin-film laminated interference plate 6. Is collimated and guided to the thin film laminated interference plate 6. The side of the thin-film laminated interference plate 6 on which the collimator lens 2 is disposed is the incident side of light from the light source 1.

In this example, each thin-film laminated interference plate 6
Has a supporting / driving structure capable of varying the angle of the parallel light from the light source 1 by electromechanical control. Can be arbitrarily changed in the angle of the light to be incident.

The slit 4 is a plate disposed on the light reflection side of the thin-film laminated interference plate 6, and is a light shielding plate, and has a slit gap 4 a corresponding to each thin-film laminated interference plate 6. .

The convex lens 5 is an array of lenses in which micro lens groups are densely arranged, and is provided so that the micro lens 5a is arranged for each pixel. Each micro lens 5a of the convex lens 5 is for magnifying the monochromatic light transmitted through the slit gap 4a of the corresponding pixel, and is for magnifying and displaying the pixel.

In such a configuration, light emitted from the light source 1 passes through the collimator lens 2 and is converted into parallel light. The parallel light is incident on the thin film laminated interference plate 6 rotatable in the direction shown in the figure by electromechanical control, and reflects light of a specific wavelength in a specific reflection direction. The reflected light goes to the slit 4, and the light of the wavelength component that reaches the slit gap 4a is emitted to the outside of the slit. Then, light of a certain single color component that has passed through the slit gap 4a is incident on the microlens 5a of the convex lens 5.

The micro lens 5a enlarges the incident light. This makes it possible to display monochromatic light in a wide field of view and perform pixel display. That is, the use of the convex lens 5 makes it possible to supplement the viewing angle dependency of the wavelength, and to obtain the same image for a wide viewing angle.

In the case of forming a display device for a display image based on seven colors by the configuration shown in this specific example,
By controlling the declination θ of the collimator lens 2 so that seven colors can be displayed, the number of pixels can be reduced to one-third of that of the conventional method in which a color screen is composed of pixels of three colors of RGB. The display screen can be configured. That is, in the present invention, light of a required wavelength is obtained by light interference and a slit during color display and is used for pixel display. Therefore, in color display, each pixel for the three primary colors of RGB which is originally required is required in principle. And one pixel of a color image can be displayed by a single pixel.

Therefore, a display device having high definition and high light use efficiency can be realized. Also, when forming a full-color display device, a polarizing plate,
By not using a color filter, a display device with higher light use efficiency can be realized. In addition, since the light use efficiency is high, a light interference type color display device having high luminance with a light source having lower power consumption than power consumed by the backlight can be obtained.

As described above, according to this example, a power-saving and high-luminance color display device can be obtained. In the above, light of a specific wavelength is emitted in a specific direction by reflecting light with a thin-film laminated interference plate, and this is observed through a slit so that color display is performed. The wavelength of light to be extracted is selected by changing the angle of light incident on the laminated interference plate by changing the angle of the thin-film laminated interference plate itself. But,
The wavelength of the light to be extracted can be selected not only by changing the angle of the light incident on the thin film laminated interference plate, but also by variably controlling the slit position. Next, a specific example of the method will be described.

(Sixth Embodiment) FIG. 8 is a sectional view showing an outline of a light interference type color display device according to a sixth embodiment of the present invention. In the light interference type color display device of this example, FIG.
As shown in FIG. 1, the light source 1 includes a light source 1, a collimator lens 2, a thin film laminated interference plate 6, a slit 4, and a convex lens 5. In this specific example, the light extracted from the thin-film laminated interference plate 6 is selectively extracted by variably controlling the slit position. For this reason, the slit 4 is configured to be supported so as to be movable in the plane direction, and is configured to be able to control the position to be electrically and mechanically movable. The collimator lens 2 and the thin-film laminated interference plate 6 are fixed at fixed positions.

In such a configuration, light emitted from the light source 1 passes through the collimator lens 2 and is converted into parallel light. The parallel light is incident on the thin-film laminated interference plate 6 and reflects light of a specific wavelength in a specific reflection direction. The reflected light goes to the slit 4, and the light of the wavelength component that reaches the slit gap 4a is emitted to the outside of the slit. Then, light of a certain single color component that has passed through the slit gap 4a is incident on the microlens 5a of the convex lens 5.

The micro lens 5a enlarges the incident light. This makes it possible to display monochromatic light in a wide field of view and perform pixel display. That is, the use of the convex lens 5 makes it possible to supplement the viewing angle dependency of the wavelength, and to obtain the same image for a wide viewing angle.

In this display device, the slit 4 is electrically and mechanically positioned so as to take out light of an arbitrary wavelength out of the specific wavelength light reflected through a specific position of the thin film laminated interference plate 6. It can be controlled to move. Therefore, the position of the slit 4 is controlled so that the slit gap 4a comes to a position where light of a desired wavelength passes. This allows
Desired specific monochromatic light is incident on the convex lens 5 through the slit 4, and by displaying the monochromatic light in a wide field of view by the convex lens 5, the pixel can be displayed with light of a desired wavelength.

According to this example, as in the fourth and fifth examples, a display device with high definition and high light use efficiency can be realized. In addition, even when a full-color display device is formed, a display device with higher light use efficiency can be realized by not using a polarizing plate and a color filter as compared with a conventional display device. In addition, since the light use efficiency is high, a light interference type color display device having high luminance with a light source having lower power consumption than power consumed by the backlight can be obtained.

As described above, according to this example, a power-saving and high-brightness color display device can be obtained. Above, light of a specific wavelength is emitted in a specific direction by reflecting light from a built-in light source on a thin-film laminated interference plate, and the color display is performed by observing the light through a slit. The wavelength of light to be extracted is selected by changing the angle of light incident on the thin film laminated interference plate by changing the angle of the thin film laminated interference plate itself.

However, in order to further reduce the power consumption, it is preferable to employ a configuration in which external light is used instead of a system incorporating a light source. Therefore, a light interference reflection type color display device which saves power by introducing external light and selecting a wavelength of light to be extracted from the introduced light will be described.

[Light interference reflection type color display device] (Seventh specific example) FIG. 9 is a sectional view showing an outline of a light interference reflection type color display device according to a seventh specific example of the present invention. The light interference reflection type color display device in this specific example is
As shown in FIG. 9, a thin film laminated interference plate 6, a substrate 8 rotatably supporting one end of the thin film laminated interference plate 6, and an angle adjustment control mechanism for controlling an angle between the substrate 8 and the thin film laminated interference plate 6 7. The thin-film laminated interference plate 6 is configured to receive external light (sunlight, indoor light, etc.) and reflect it.

In this specific example, a backlight as a built-in light source and no light source are used, so that power consumption is lower than that of a conventional display device. The specific example of FIG. 9 shows three pixels, and shows a state in which the angles formed by the thin-film laminated interference plate 6 and the substrate 8 are θ1, θ2, and θ3, respectively. As described above, from the relationship between the wavelength λ of the light reflected from the thin-film laminated interference plate 6 and the incident angle φ of the light to the thin film, it is possible to display light of different wavelengths depending on each angle.

Further, when used in a portable device, an accelerometer, a laser gyro, or the like is incorporated in the portable device housing, and when the incident angle of ambient light is changed by tilting the portable device housing, the thin film laminated interference plate is used. 6 changes the angle to maintain the proper display.

According to such a light interference reflection type color display device, an image to be displayed is almost one as shown in FIG.
The display is performed with an aperture ratio of 00%. In contrast,
In the display of the conventional type, the display area has to be framed as shown in FIG. 12 to reduce the aperture ratio.
It is clear that the embodiment of the present invention has a higher aperture ratio.

According to this specific example, it is possible to obtain a light interference reflection type color display device capable of further reducing power consumption and securing a pixel display area with an aperture ratio of almost 100%. Note that the present invention is not limited to the specific examples described above, and can be implemented in various modifications. For example, each of the above-mentioned specific examples has a configuration capable of full-color display. For this purpose, a white light source is used as a light source. However, in the case of a display device that requires a specific color, such as a display based on two colors, a light source including only the necessary color may be used.

[0095]

As described above, according to the present invention, there is provided a color display device which has a higher light use efficiency, a higher aperture ratio and lower power consumption than the conventional liquid crystal display device. I can do it.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an outline of first to third specific examples of the present invention.

FIG. 2 is a sectional view showing an outline of a first specific example of the present invention.

FIG. 3 is a sectional view showing an outline of a second specific example of the present invention.

FIG. 4 is a sectional view showing an outline of a third specific example of the present invention.

FIG. 5 is a sectional view showing an outline of fourth to sixth specific examples of the present invention.

FIG. 6 is a sectional view showing an outline of a fourth specific example of the present invention.

FIG. 7 is a sectional view showing an outline of a fifth specific example of the present invention.

FIG. 8 is a sectional view showing an outline of a sixth specific example of the present invention.

FIG. 9 is a sectional view showing an outline of a seventh specific example of the present invention.

FIG. 10 is a diagram illustrating an aperture ratio in a light interference reflection type color display device of the present invention.

FIG. 11 is a cross-sectional view illustrating a structural example of a transmissive liquid crystal display.

FIG. 12 is a diagram illustrating an aperture ratio of a conventional display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Light source 2 ... Collimator lens 3 ... Prism 3a ... Microprism part 4 ... Slit 4a ... Slit gap part 5 ... Convex lens 5a ... Microlens 6 ... Thin film multilayer interference plate 7 ... Thin film multilayer interference plate and the substrate supported Apparatus for controlling an angle 8 ... Substrate 21 ... Array substrate 22 ... TFT 23 ... Liquid crystal 24 ... Backlight 25 ... Pixel electrode 26 ... Polarizing plate 27 ... Color filter 28 ... Counter substrate

Claims (3)

[Claims] A light source; a parallel light converting means for converting an output light of the light source into a parallel light; a light separating means for separating the converted parallel light; and a light incident on the light separating means from the light source. A means for changing the angle, a slit provided for the pixel, for selecting and extracting light that passes only light of substantially a single wavelength out of the light of each wavelength separated by the spectral means, and a slit provided for the pixel. Means for enlarging the single-wavelength light extracted by the slit so as to allow a wide viewing angle to be visually recognized. 2. A flat plate which is formed by laminating thin films having different refractive indices in multiple layers and causes incident light to be reflected by causing light interference, and substantially one of the light reflected and interfered by the flat plate. A color display device comprising: a slit for selectively extracting light that passes only light having a wavelength; and a unit for changing an incident angle of the interference reflected light to the slit. 3. A flat plate which is formed by laminating a plurality of thin films having different refractive indexes and reflects incident light by causing optical interference, and means for changing an angle of the light incident on the flat plate. A color display device.