JPH01126625A - Color display device - Google Patents

Abstract

PURPOSE:To improve luminance and to enable full-color display by obtaining light emission output in series with time with respect to 1st and 2nd wavelength light and obtaining light emission output in parallel with respect to 1st and 2nd wavelength light. CONSTITUTION:The ZnO:Zn phosphors 203 of a desired pattern corresponding to green and blue are driven to emit light in series with time in every 1/2 frame period and a liquid crystal cell 103 is driven to an on or off state in the case of mixing red, green and blue colors. Y2O2S:Eu phosphors 204 of a desired pattern corresponding to red are simultaneously driven to emit light in parallel therewith. The driving in the 1/2 frame period is, therefore, executed for the green and blue colors and the driving in the full-frame period is possible for the red color. The higher-brightness and full-color display is thereby enabled more satisfactorily than in the case of driving the green, blue and red colors serially in this order.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a color display device, and more particularly to a field sequential color display device using a fluorescent display device.

(Prior Art) As one type of color display device, there is a field sequential color display device that combines a light emitting display device that generates an image with a color polarizing plate and a liquid crystal shutter for selecting the wavelength of transmitted light. (Refer to Japanese Patent Application Laid-open No. 126515/1983), because the color display device uses a field sequential method rather than a juxtaposed color mixing method.

It becomes possible to improve display resolution. On the other hand,
In order to achieve full color display, a light emitting display device is required to have the ability to emit light over a wide wavelength range. Therefore, when a fluorescent display device is used as a one-emission display device, ZnO:Zn is used as a phosphor, which has the widest emission wavelength range and has excellent characteristics such as longevity. However, ZnO has an emission spectrum that spans almost the entire visible region.
: Even in the case of Zn phosphors, the emission brightness in the red region is low, which is an obstacle to achieving full-power colorization.

Therefore, it is conceivable to arrange a red-emitting phosphor near the ZnO:Zn phosphor and use both the field sequential method and the co-located color mixing method. This display device is driven by blue,
The part shown in green causes ZnO:Zn to emit light, and the part shown in red causes red light emitting phosphor to emit light. By appropriately driving the liquid crystal shutter in synchronization with this, the red display section, the green display section, and the blue display section are displayed line by line or field by field in this order.

(Problems with the Prior Art) Full-color display is possible by increasing the amount of red light emitted as described above. However, there are phosphors that can emit red light such as Loss:Eu, but the luminous efficiency of these phosphors is only about 2% of that of ZnO:Zn.Therefore, the brightness of red is lower than that of blue and green. It has the disadvantage of being low and causing display unevenness.

To improve this, we have added a red display section and a green display section.

It is conceivable to make the blue display part emit light in order and to make the red display part emit light for a longer time. Even in this method, since the frame period is a constant value, there is a problem in that if the light emitting time of the red display section is lengthened, the light emitting time of other colors becomes shorter, and the overall brightness decreases.

(Means for solving the problems) The present invention has the following features: a fluorescent display section having a first light emitting section that emits light with a luminance of a predetermined value or more in a specific wavelength region that includes a light component of a second wavelength; and a second light emitting section that emits light that includes a light component of a third wavelength; an optical rotation part that transmits light from the fluorescent display section, a neutral polarizing plate disposed across the optical rotation part, a first color polarizing plate that transmits light of the first and third wavelengths, and the second and third wavelengths. a second color polarizing plate that transmits light of three wavelengths; a display drive section that drives the first and second light emitting sections in parallel according to one display section number; and a display drive section that drives the optical rotation characteristics of the optical rotation section in synchronization with the driving. It is equipped with a control section that changes the

(Effect) 1st. For the second wavelength light, the light emission output is obtained temporally in series, and for the third wavelength light, the first... Since the light emission output is obtained in parallel with the second wavelength light, it is possible to achieve full color while improving brightness.

(Example) FIG. 1 is a diagram showing a schematic configuration of the present invention.1 Display section 10
The emitted light according to the display pattern No. 1 is polarized by the neutral polarizing plate 102, and only the light polarized in the direction of arrow C1 enters the liquid crystal cell 103. The liquid crystal cell 103 is provided with solid transparent electrodes on the opposing surfaces of two transparent substrates.
A chiral smectic C-phase liquid crystal, which is a ferroelectric liquid crystal, is sealed between them. The light passing through the liquid crystal cell 103 is
A color polarizing plate 104 having a polarization axis C8 that transmits white light and a polarization axis C3 that transmits violet light that is a mixture of red and blue, a polarization axis C6 that transmits white light, and a polarization axis C6 that transmits yellow light that is a mixture of green and red. Light of a desired color is emitted through the color polarizing plate 105 having a transmitting polarization axis C1.

The display section 101 and the liquid crystal cell 103 each have a display drive circuit 1.
08, driven by the liquid crystal drive circuit 107. The driving is synchronously controlled by a timing control section 1111106.

FIGS. 2(a) and 2(b) are a bottom sectional view and a partial front view of the display section 101 used in the apparatus shown in FIG.

In FIG. 2, a strip-shaped anode conductor 202 is deposited on a substrate 201 made of glass or the like, and a ZnO:Zn fluorescent material is placed on top of the strip-shaped anode conductor 202, which serves as a first light emitting part that emits light containing light components of first and second wavelengths. 25th to eliminate light including the body 203 and the light component of the third wavelength
1! Y, O, S:Eu phosphors 204, which become the light part, are alternately deposited.Instead of Y*OJ:Eu phosphor,
A wire-shaped control electrode 206 supported by a support 205 is stretched over the Zn,Cd)S:Ag,C phosphor. Control electrode 2
06 is a linear cathode electrode 207 in a crossing direction.
is provided. Each electrode consists of a substrate 201, a side plate 20
For simultaneous selection of zero pixels held within the outer wall formed by J1 and the front plate 209, a display signal is input in parallel to each anode electrode 202, and two adjacent wire-shaped control electrodes 206 are simultaneously selected. @ZnO:Zn phosphor 203. Y, O.

A region P in which a set of one anode electrode each coated with the S:Eu phosphor 204 is sandwiched between two adjacent control electrodes constitutes one pixel.

FIG. 3 is a drive timing diagram of the color display device of FIG. 1. Moreover, FIG. 4 shows the light transmission characteristics of the filters used in the same device, and 401 and 402 respectively indicate the color polarizing plate 10.
4,105.

The operation will be explained below with reference to FIGS. 1 to 4.

First, we will explain how to display a desired pattern in green.

The ZnO:Zn phosphor 203 is driven to emit light in a desired pattern. At the same time, the liquid crystal cell 103 is turned on. In the on state, the liquid crystal cell 103 does not rotate the incident light, but outputs the incident light while maintaining its polarization state. Therefore, the light from the display section 101 is polarized in the 01 direction by the neutral polarizing plate 102, and then the light polarized along the polarization axes c, c, of the color polarizing plates 104 and 105 is output. At this time, since the red component included in the light emission of ZnO:Zn is extremely small, almost only the green light component is output.

Next, when displaying a blue pattern, Z of 1 display section 101
nO: Displays a desired pattern using Zn and turns off the liquid crystal cell 103. Neutral polarizing plate 10
The light polarized in the 02 direction at 2 is rotated by 90 degrees by the liquid crystal cell 103 and then output. The output light of the liquid crystal cell 103 is polarized by the polarization axes C, , C of the color polarizing plates 104 and 105.
Since the red component included in the light emission of 5ZnO:Zn is extremely small, only the blue light component is output.

Next, when displaying a red pattern, driving is performed in parallel with the above-described driving of green and blue. That is, Y, O, S:t! on the display section 101. When the u phosphor 204 is driven to emit light in a desired pattern, this output light is polarized in the 01 direction by the neutral polarizing plate 102 and sent to the liquid crystal cell 103.
It is output via color polarizing plates 104 and 105. In this case, when the liquid crystal cell 103 is on, the color polarizing plate 10
4,105 polarization axis C! , C4, and when the liquid crystal cell 103 is off, the color polarizing plates 104 and 105
is output via the polarization axes C3, C3.

Therefore, red display light is output regardless of whether the liquid crystal cell 103 is on or off.

When mixing red, green, and blue colors, as shown in FIG. 3, the desired pattern of ZnO:Zn phosphors 203 corresponding to green and blue colors are emitted in series in time for 172 frame periods. At the same time, the liquid crystal cell 103 is turned on or off. At the same time, as shown in FIG. 3, the desired pattern Y, O, S corresponding to red:
The Eu phosphor 204 is driven to emit light.

As a result, green and blue colors can be driven for 1/2 frame period, and red color can be driven for a whole frame period. Therefore, compared to the case where green, blue, and red are driven in series in that order, it is possible to achieve higher brightness and full color in a better manner. still.

Even when the brightness of red is lower than that of blue and green as in this embodiment, the brightness of red can be improved, making it possible to achieve full color.

If the spectral transmission characteristics of the color polarizing plates 104 and 105 are poor, the spectral transmission characteristics of the color polarizers 104 and 105 are 1±, and by using an auxiliary filter with transmission characteristics as shown by the dashed line 403 in FIG.
Color characteristics can be improved without interfering with the source color light.

In this embodiment, a ferroelectric liquid crystal cell was used as the liquid crystal cell 103, but various types of liquid crystal cells such as twisted nematic liquid crystal, dual-frequency driving type liquid crystal cell, π cell (see Japanese Patent Application Laid-open No. 59-219720), and PLZT Crystalline birefringent materials can also be used.

(Effects of the invention) 1. Since the second wavelength light is obtained in temporal series, and the third wavelength light is obtained in parallel with the first and second wavelength lights, it is possible to achieve full color while improving brightness. It becomes possible.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of the present invention, FIG. 2 is a bottom sectional view and partial front view of the display unit used in the present invention, FIG. 3 is a timing diagram of the display device in FIG. 1, and FIG. FIG. 3 is a characteristic diagram of a filter used in the invention. 101: Display section, 102: Neutral polarizing plate, 103
:Liquid crystal cell, 104.105: Color polarizing plate Patent applicant: Futaba Electronics Co., Ltd. Figure 1 Figure 2 (a)

Claims (2)

[Claims] (1) It has a first light emitting part that emits light with a luminance of a predetermined value or more in a specific wavelength range that includes light components of first and second wavelengths, and a second light emitting part that emits light that includes light components of a third wavelength. a fluorescent display section, an optical rotation section that transmits light from the fluorescent display section, and a neutral polarizing plate disposed across the optical rotation section;
a first color polarizing plate that transmits the light of the first and third wavelengths; a second color polarizing plate that transmits the light of the second and third wavelengths; and the first and second light emitting parts according to the display signal. A color display device comprising: a display drive unit that drives the optical rotation unit in parallel; and a control unit that changes the optical rotation characteristics of the optical rotation unit in synchronization with the drive. (2) A patent characterized in that the first light emitting part is formed of a ZnO:Zn phosphor, and the second light emitting part is formed of a (Zn, Cd)S:Ag, Cl or V_2O_2S:Eu phosphor. A color display device according to claim 1.