JPH01124826A - Color display device - Google Patents

Abstract

PURPOSE:To uniformize the luminances of respective light rays of 3 primary colors so that high-grade color display without having unequal displays is executed by combining optically rotatory parts and polarizing plates with a fluorescent display part having two light emitting parts which are different in light emission characteristics and synchronously driving the display part and the optically rotatory parts. CONSTITUTION:The fluorescent display part 301 and liquid crystal cells 303, 305 are synchronously driven. The cells 303, 305 turn off and the display part 301 emit red light when display data is given to one anode of the display part 301. This red light is passed through the plural optically rotatory parts 303, 305 and the plural color polarizing plates 302, 304 and is outputted as the red light within the perpendicular plane from the polarizing plate 306. Band-shaped spectral light is emitted when the display data is applied to the other anode of the display part 301. The cells 303, 305 are turned on in synchronization therewith and the green light within the perpendicular plane is outputted from the polarizing plate 306; further, the blue light is outputted. The respective light rays are thereby taken out with the uniform luminances. The high-quality color display without having the unequal displays is thus executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a color display device capable of displaying characters, figures, etc. in multiple colors, and particularly relates to an improvement of a color display device using a color polarizing plate. It is.

[Prior Art] FIG. 5 is a schematic exploded view showing the basic structure of a conventional color display device using color polarizing plates. This color display device has a fluorescent display section 105 that emits light in a band-like spectrum to display characters, figures, etc., and allows only white light of a predetermined direction component to pass in front of the fluorescent i-receiving section 105. A neutral polarizing plate 104 is provided.

In front of the neutral polarizing plate 104, a twisted nematic liquid crystal cell 103 (hereinafter referred to as TN liquid crystal cell 103) is provided, in which transparent electrodes are adhered solidly over the entire surface of both substrates. This TN liquid crystal cell 103 has a transparent electrode of OF
When the F signal is given, the neutral polarizing plate 104
The incident light is rotated by 90 degrees and outputted, and when an ON signal is given, the incident light is output as is without being rotated. And TN liquid crystal cell 1
In front of 03, two color polarizing plates 101 and 102 are provided. As shown in FIG. 5, one color polarizing plate 102 can output white light and blue light in two directions orthogonal to each other, and the other color polarizing plate 101
is capable of outputting red and white light in two directions orthogonal to each other. The TN liquid crystal cell 103 is connected to a liquid crystal drive circuit 106, and the fluorescent display section 105 is connected to a display drive circuit 108. Both drive circuits 106
, 108 are both connected to a timing circuit 107, and each drive circuit 106, 108 connects the TN liquid crystal cell 103 while synchronizing with a signal generated by the timing circuit 107.
It is configured to drive the fluorescent table, the fluorescent table, and the support part 105, respectively.

Next, the operation of such a conventional color display device will be explained. First, the display image of the fluorescent display unit 105 such as images and characters is composed of randomly polarized light components, and among these light components, only the white light component in a predetermined direction of the neutral polarizing plate 104 indicated by the arrow is the neutral polarized light. It passes through plate 104. Here, when the TN liquid crystal cell 103 is OFF, the polarized light incident from the neutral polarizing plate 104 is rotated by 90 degrees and output. Therefore, white light is output from the first color polarizing plate 102, and this light is transmitted to the second color polarizing plate 10.
1, and only red light is output from the second color polarizing plate 101. That is, the display on the display unit 105 becomes red. Now, when the TN liquid crystal cell 103 is ON, the light passing through the neutral polarizing plate 104 enters the first color polarizing plate 102 while maintaining its polarized state, so blue light is emitted from the same color polarizing plate 102. Output. Therefore, blue light is also output from the second color polarizing plate 101, and the display on the fluorescent display section 105 becomes blue.

In this way, by synchronizing the display drive of the fluorescent display section 105 and the drive of the TN liquid crystal cell 103, color display can be realized using the monochrome fluorescent display section 105.

[Problems to be Solved by the Invention] As described above, when attempting to perform color display in various colors from red to blue, the fluorescent display section 105 uses light with a wide band-like spectrum from red to blue. must be output. If the brightness level of the band spectrum is not uniform for each color, there will be a difference in display brightness for each color to be displayed, and if a display is formed by a color with low brightness and a color with high brightness, the display screen There was a problem in that unevenness occurred. For example, in the emission spectrum of the phosphor ZnO:Zn used in the fluorescent display section 105, the brightness of the red component is low, as shown in FIG. Therefore, in the color display device, ZnO: Zn
If the fluorescent display section 105 having only a fluorescent light is used, display unevenness will occur.

[Means for Solving the Problems] The color display device of the present invention includes a first light emitting section that emits band-like spectrum light having a luminance of a predetermined value or more in a specific wavelength region, and a second light emitting section that emits light outside the specific wavelength region. a plurality of optical rotation parts that transmit light from the fluorescent display parts; a neutral polarizing plate field and a plurality of color polarizing plates provided between the optical rotation parts; It is characterized by comprising a display drive unit that drives a display unit, and a control unit that controls optical rotation characteristics of the optical rotation unit in synchronization with the drive.

[Operation] First, a band-shaped spectrum light in a specific wavelength range is emitted from the first light emitting section of the fluorescent display section by driving the display drive section.

The band-like spectrum light is generated by a combination of the action of a neutral polarizer or a plurality of color polarizers that transmit light of a predetermined wavelength in a predetermined direction component, and the action of an optical rotation part driven by a control part in synchronization with the display drive part. When the second light emitting section emits light outside the specific wavelength range due to the drive of the 0-order 1 display drive section, the light with a desired wavelength is selected and output from the display drive section. The light passes through the optical rotation unit driven by the control unit and each of the polarizing plates, and is output as is.

[Example] An embodiment of the present invention will be described with reference to FIGS. 1 to 4.

FIG. 1 is a schematic exploded view showing the basic structure of the color display device of this embodiment. In the figure, 301 is a fluorescent display section which is a light emitting part of this device, and this fluorescent display section 30
1 has the same basic structure as a fluorescent display tube, which is widely used as a display element. That is, Fig. 2(a), (
As shown in b), l is an envelope assembled into a box shape, the inside of which is evacuated to a high vacuum state. Envelope 1
On the inner surface of the substrate 2, which forms part of the substrate 2, a plurality of strip-shaped anodes 3, each having a phosphor coated on its upper surface, are arranged parallel to each other at predetermined intervals. These anodes 3 arranged in a stripe shape are divided into two groups with a negative line between them, and one group, each anode 3a serving as a first light emitting part, is coated with a phosphor ZnO:Zn. Each anode 3b serving as the second light emitting section in the other group is coated with a phosphor Y20. S: Eu is deposited. As explained in the [Prior Art] section, the phosphor ZnO:zn emits band-like spectrum light with a brightness above a predetermined value in a specific wavelength range including green and blue, but the brightness of the red component is low. On the contrary, the phosphor Y202 S :Eu emits red light with a brightness higher than a predetermined value. Above these anodes 3, a plurality of wire-shaped control electrodes 4 are stretched parallel to each other at predetermined intervals so as to be orthogonal to the longitudinal direction of the anodes 3, and each of the anodes 3g, 3b Together, they form a matrix display surface. A plurality of filament-shaped cathode electrodes 5 serving as electron emission sources are stretched above the control electrode 4 . The various electrodes of the fluorescent display section 301 are led out of the envelope 1 and connected to a display drive circuit 3 as a display drive section.
07, and the display drive circuit 307 is connected to a timing circuit 310. Therefore, if the display drive circuit 307 scans the control electrode 4 and simultaneously provides display data synchronized with the scanning to the anode 3a or 3b, the fluorescent display section 301 selectively drives either the anode 3a or the anode 3b to emit light. be able to.

Next, in front of the fluorescent display section 301, first and second
The first and second TN liquid crystal cells 303.
305 is provided. These TN liquid crystal cells 303
, 305 has almost the same configuration as that described in the [Prior Art] section.

Each TN liquid crystal cell 303, 305 has a first
and second liquid crystal drive circuits 308 and 309, respectively. Each of the liquid crystal drive circuits 308 and 309 is connected to the timing circuit 310, so that the optical rotation characteristics of each of the TN liquid crystal cells 303 and 305 can be controlled in synchronization with the drive of the fluorescent display section 301 by the display drive circuit 307. It is composed of

Next, the fluorescent display section 301 and the first TN liquid crystal cell 30
3, a first color polarizing plate 302 is provided. This color polarizing plate 302 can pass white light in the vertical plane and blue light in the horizontal plane, which are two-way components perpendicular to each other. Next, the first TN liquid crystal cell 303
A second color polarizing plate 304 is provided between the second TN liquid crystal cell 305 and the second TN liquid crystal cell 305 . This color polarizing plate 304
can pass green light in the vertical plane and white light in the horizontal plane, which are two-way components perpendicular to each other. In front of the second TN liquid crystal cell 305, a neutral polarizing plate 306 is provided that allows only white light in the vertical plane to pass through.

Next, the operation of the configuration described above will be explained. As shown in Fig. 4, this device converts one frame of the drive timing chart into three colors: R (red), G (green), and B (blue).
The fluorescent display section 301 and TN liquid crystal cells 303 and 305 are driven in synchronization with each other by a timing circuit 310. First, in the field of R,
Display data is given to one anode 3b of the fluorescent display section 301, and the phosphor Y202 S: Eu of the one anode 3b
emits red light. In synchronization with this, both TN liquid crystal cells 30
3 and 305 are both turned off. Fluorescent display section 30
The red light emitted from the first color polarizing plate 302 is composed of random polarization components and becomes red light in the vertical plane after passing through the first color polarizing plate 302. Next, this red light is rotated by 90 degrees in the first TN liquid crystal cell 303 to become red light in the horizontal plane, passes through the second color polarizing plate 304, reaches the second TN liquid crystal cell 305, and is rotated by 90 degrees again. The light is optically rotated and becomes red light in the vertical plane, which is output from the neutral polarizing plate 306. Next, in the G field, display data is given to the other anode 3a of the fluorescent display section 301, and the phosphor ZnO:Zn of the anode 3a emits band-like spectrum light. In synchronization with this, both TN liquid crystal cells 303 and 305 are turned on. The band-like spectrum light from the fluorescent display unit 301 is composed of random polarization components in a specific wavelength range, but when it passes through the first color polarizing plate 302, it becomes only white light in the vertical plane and blue light in the horizontal plane. . These lights pass through the first TN liquid crystal cell 303 without being rotated and enter the second color polarizing plate 304. Green light in the vertical plane and blue light in the horizontal plane are output from the second color polarizing plate 304, and this light is transmitted to the second T without being rotated.
It passes through the N liquid crystal cell 305. The green light and blue light then enter the neutral polarizing plate 306, and only the green light in the vertical plane passes through this and is output. Next, in the B field, similar to the G field, display data is given to the other anode 3a of the fluorescent display section 301, and the phosphor ZnO:Zn of the anode 3a emits band-like spectrum light.

In synchronization with this, the first TN liquid crystal cell 303 is turned on, and the second TN liquid crystal cell 305 is turned off. When the band-shaped spectrum light from the fluorescent display section 301 passes through the first color polarizing plate 302, it becomes only white light in the vertical plane and blue light in the horizontal plane. These lights pass through the first TN liquid crystal cell 303 without being rotated and enter the second color polarizing plate 304. From the second color polarizing plate 304,
Green light in the vertical plane and blue light in the horizontal plane are output, but
These lights are focused at 90° by the second TN liquid crystal cell 305.
Since the light is rotated and enters the neutral polarizing plate 306,
Neutral polarizing plate 306 outputs only blue light in the vertical plane.

As described above, according to the color display device of this embodiment, the display of G and H is obtained by the time-divisional light emission of the anode 3a having the phosphor ZnO:Zn, and the phosphor ZnO:Zn
The lack of red characteristics in the anode 3b can be improved by adding the phosphor Y20. S: Obtained by Eu emission. That is, this device can make the brightness of each color of R, G, and B uniform by using time-division color mixing together with juxtaposed color mixing, and can realize high-quality color display without unevenness. Further, as a phosphor having red characteristics, (Zn, Cd)S 2 :Ag, cl can also be used.

In addition, in the above embodiment, the light emitting part of the fluorescent display part 301 was constituted by the striped anodes 3a and 3b, but other shapes and arrangement patterns of the anode 3, which is the light emitting part, can be considered. . For example, as shown in FIG. 3, a dot-shaped anode 13a having a phosphor ZnO:Zn and another dot-shaped anode 13b having a phosphor Y2O2S:Eu are arranged vertically and horizontally at a predetermined pitch. Good too.

In this case, the bare pixel pitch of the anode 13a and the anode 13b needs to be maintained at the same level as the conventional pixel pitch. In addition, although an example in which a TN liquid crystal cell is used as the optical part has been described, super twisted nematic liquid crystal cells, ferroelectric liquid crystal cells such as chiral smectic C phase, π
In addition to liquid crystal cells such as JP-A No. 59-219720, crystalline birefringent materials such as PLZT can also be used.

[Effects of the Invention] According to the color display device of the present invention, two display devices having different light emission characteristics can be used.
By combining a fluorescent display section with two light-emitting sections with an optical rotation section and a polarizing plate, and driving the fluorescent display section and optical rotation section in synchronization, each of the three primary colors can be extracted with uniform brightness, thereby reducing display unevenness. This has the effect that it is possible to realize high-quality color display that is not available in the past.

[Brief explanation of the drawing]

FIG. 1 is a schematic exploded perspective view showing the basic structure of an embodiment of the present invention, FIG. 2(a) is a sectional view of a fluorescent display section in the same embodiment, and FIG. A schematic plan view showing the electrode structure, FIG. 3 is a diagram showing another pattern of the light emitting part in the fluorescent display section of the embodiment, FIG. 4 is a drive timing chart of the above embodiment, and FIG. 5 is a diagram of the conventional color display. A schematic exploded perspective view showing the basic structure of the display device, FIG. 6 shows the phosphor Z
It is a figure showing the emission spectrum of nO:Zn. 3a, 13a--Anode as first light emitting part, 3b, 13
b-Anode as second light emitting part, 301-Fluorescent display part, 302--First color polarizing plate, 303--First TN liquid crystal cell as optical rotation part, 304
・-Second color polarizing plate, 305-Second TN liquid crystal cell as optical rotation part, 306・
- Neutral polarizing plate, 307 - Display drive circuit as display drive unit, 308 -
- a first liquid crystal drive circuit as a control section; 309-- a second liquid crystal drive circuit as a control section; Patent Applicant Norimitsu Nishimura Futaba Electronics Co., Ltd. Agent/Patent Attorney Figure 2 (a) (b) 3rjA Rororo Exit Figure 4 Figure 51!1

Claims (3)

[Claims] (1) A fluorescent display section including a first light emitting section that emits a band-shaped spectrum light having a luminance of a predetermined value or more in a specific wavelength region and a second light emitting section that emits light outside the specific wavelength region; a plurality of optical rotation parts that transmit light, a neutral polarizing plate and a plurality of color polarization plates provided across the optical rotation parts, a display drive part that drives the fluorescent display part, and a display drive part that drives the fluorescent display part; A color display device comprising: a control section that controls optical rotation characteristics of the optical rotation section. (2) The first and second light emitting parts are made of ZnO:Zn and Y, respectively.
_2O_2S: The color display device according to claim 1, characterized in that it contains Eu. (3) The first and second light emitting parts are made of ZnO:Zn, (
2. The color display device according to claim 1, comprising: Zn, Cd)S:Ag, Cl.