JPS61103186A - Lighting source - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

TECHNICAL FIELD The present invention relates to a light source for illumination, and more particularly to a light source for illumination useful as a light source for a liquid crystal color display device using a liquid crystal element as a light switching element.

Conventional technology Conventionally, CRT (cathode ray tube) was used as a color display device.
A typical example is one that uses the same technology, and is often used in television display devices and OA (office automation) equipment. However, since this CRT is a type of large cone-shaped vacuum tube, a display device using a CRT requires a high-voltage power supply, a complicated drive circuit, and the entire device must be large. However, there was a limit to how thin the device could be.

In recent years, panel-type liquid crystal display devices using liquid crystals have been actively developed, and here are the recent results.

It has appeared as an LCD color pocket TV. This is a magazine [Nikkei Electronics, 1983, 5-2
3. As described in the article ``P., 102-103,'' a glass substrate with red, green, and blue color filters attached to each pixel and another transparent substrate with an integrated thin film transistor array. A TN-type liquid crystal is sealed in the liquid crystal, and this is sandwiched between two polarizing plates to form a liquid crystal panel.

A white illumination light source is placed behind it.

Thin film transistors are built to correspond to the red, green, and blue color filters of each pixel, and perform a light switching function.

However, although such liquid crystal color display devices can be made thinner, they use a white light source and optical filters to display color, so the color development and color reproducibility are insufficient, and the contrast is insufficient, making it difficult to see. There was a drawback.

Viewing Example 1 The present invention relates to an illumination light source that emits bright and clear chromatic light and is suitable for high-quality color display.

In the illumination light source of the present invention, a phosphor layer containing a phosphor that emits colored light and a colored filter that transmits light from the phosphor layer are formed on a tube wall, and the phosphor layer includes a phosphor layer that transmits light from the phosphor layer. It is characterized by having an internal radiation source of electromagnetic waves that can cause

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of the illumination light source of the present invention, and FIG. 2 is a partially cutaway perspective view.

The outer surface of the tube wall 13 of the illumination light source 11 is coated with red (R) and green (
G) and blue (B) unit color pixel filter sections 18a
, 18b and 18c are provided in a mosaic pattern. Further, on the inner surface of the tube wall of the illumination light source 11, a phosphor layer 22 consisting of a phosphor pixel portion 21 is provided.
Each of the phosphor pixel portions 22a, 22b, and 22c includes a phosphor R1 that emits red light, a phosphor G that emits green light, and a phosphor B that emits blue light. A filament 55 is disposed inside the illumination light source, and
Contains mercury and argon. filament 5
When energized, thermoelectrons are emitted, and the thermoelectrons ionize argon and mercury to emit ultraviolet light. The emitted ultraviolet light causes the phosphors R, G, and B to emit light, and this light is further transmitted to the pixel filter section 18a of the colored filter 17.

Chromatic light is transmitted from the illumination light source 11 through 18b and 18c. The light emitted by the phosphor layer is fluorescent, so it is bright, and furthermore, this R 1
゜The light obtained when the G and B fluorescence passes through the R, G, and B pixel filters is the product of the fluorescence wavelength characteristics and the wavelength characteristics of the pixel filter, resulting in more monochromatic light with a sharp rise and small half-value width. 2, resulting in bright chromatic light.

For example, if the spectral wavelength characteristics of fluorescence G from a green phosphor are as shown in FIG. 3, when this fluorescence enters the green (G) pixel filter 18b with the characteristics shown in FIG.
The transmitted light is as shown in Figure 5, and a clear cut G light that is closer to monochromatic light is obtained. In this case as well, since the fluorescence from the phosphor has a large amount of light energy, bright chromatic light can be obtained even if it is transmitted through a color filter. Furthermore, only the emission of phosphor can produce R and G.

Although the emission brightness and emission color purity of B are different, these are compared to R and G.
, H can be adjusted by colored filters, so that
If this illumination light source is used for color display, images with good color reproducibility can be realized.

FIG. 6 is a sectional view showing another embodiment of the present invention, in which a phosphor layer 2 provided on the inner surface of the tube wall 13 of the illumination light source 11 is shown.
1 contains a mixture of phosphors R, G and B. When ultraviolet light is emitted to the phosphor layer 21, mixed fluorescence of R, G, and B is generated, and this mixed fluorescence is transmitted to the colored filter 17.
R light enters from the red pixel filter 18a, G light from the green pixel filter 18b, and blue pixel filter 18c.
B light is transmitted from the This embodiment is advantageous over the one shown in FIG. 1 in that it is not necessary to form the phosphor layer in a pixel shape, but on the other hand, the effective amount of fluorescence incident on the pixel filter is reduced. The one shown in Figure 1 is superior. That is, in the case shown in FIG. 1, for example, the pixel phosphor portion R22a is formed in the phosphor layer 21 corresponding to the red pixel filter 18a, so that the light energy is effectively utilized by the luminescence of the phosphor. It is possible to obtain a large amount of R light. On the other hand, in the one shown in FIG. 6, the phosphor layer 21 corresponding to the red pixel filter 18a includes the phosphor R,
Contains a mixture of G and B. The light emitted from the phosphors G and B in this portion is not utilized, and the optical energy of the obtained R light becomes smaller accordingly.

FIG. 7 is a cross-sectional view showing another example of illumination light source 1.
A pixel-shaped phosphor layer 21 is provided on the outer surface of the phosphor layer 1, and R, G, and B pixels are provided on the outer surface of the phosphor layer 21, respectively.
A colored filter I7 matched with the G and B pixel portions is provided. In this case, as the material for the tube wall 13 of the illumination light source, it is desirable to use a material that efficiently transmits ultraviolet light, such as quartz glass, Pyrex, Vycor (manufactured by Corning Glassworks), or the like.

FIG. 8 shows still another configuration example, and in FIG. A membrane 19 is provided. Furthermore, if the reflective film is made of aluminum, silver, or the like, it can also be used as an electrode in a rabbit start method for improving the start-up when the illumination light source 11 is turned on.

Above, we have described a light source that illuminates with a collective luminous flux of R, G, and B lights, which are 3gK colors, by combining R, G, and B pixel filters and phosphors R2G and B. The light source is a full-color light source. It is suitable as a light source for color display. However, the illumination light source of the present invention is not limited to this. For example, a single chromatic filter may be combined with a phosphor layer that emits fluorescence in overlapping characteristic wavelength regions to emit a single chromatic color. It can also be used as a light source for illumination.

Next, each component will be explained in more detail.

The phosphor layer is formed by fixing on a transparent substrate (tube wall) phosphors that develop colors as R2O and B when irradiated with ultraviolet light. In addition, the phosphor layers are R, G, and B, respectively.
When forming a mosaic pixel phosphor portion that emits light, for example, the same formation method as that used in manufacturing cathode ray tubes for color televisions can be used, and
In this invention, there is no need to use the phosphor in a vacuum, and since it can be configured as a flat surface, it can be formed using a printing technique similar to gravure three-color printing. Furthermore, the R2O,H phosphor pixel portion can also be patterned by a lithography method using a photoresist. The phosphor layer can also be formed from a phosphor that emits any chromatic color.

Powder phosphors are mainly used, and Y20□5 is a rare earth-based phosphor that emits red light.
:Eu (yttrium oxide: European) system, Y, O
, :Eu (yttrium oxide: European) type, etc., and those that emit green light include ZnS.
i03 (Mn) (manganese doped zinc silicate) system, ZnS:CuA (zinc a: aluminum doped) system.

(Zn-Cd)S:Cu (zinc sulfide, cadmium: copper doped) system or those in which the above copper dope is replaced with silver (Ag) dope, and those that emit blue light include Z
nS:Ag (zinc sulfide: silver doped) system, (ZnS, Z
n0):Ag (@zinc oxide, zinc oxide: silver doped) system, etc. are exemplified.

Colored filters are produced using photolithography, electrodeposition, vacuum evaporation, printing, etc.Dichroic mirrors and dye filters made of multilayer films of high refractive index materials and low refractive index materials are used, but the latter method is advantageous in terms of cost. As the dye for the dye filter, Lanyl Red GO (Lanyl re G O) is used for the red dye filter.
d GG), Suminol Milling Yellow MR (Suminol milling yellow MR) for the green pixel filter.
ing yellowMR).

Cibacron Turkois Blue TO-E (Cib
acron turquoise blue TG-E
), cyanine 6B (Cy
anine 6B) and the like.

The illumination light source of the present invention can emit bright and clear chromatic light and can be made thin, so it is suitable as a light source for color displays, and is particularly suitable as a light source for liquid crystal color display devices. It is suitable as The illumination light source of the present invention is not limited thereto, and can be used as a light source that emits chromatic light, for example, as a color light source for writing and displaying.

A liquid crystal color display device includes a liquid crystal element that transmits electromagnetic waves in accordance with image information, and a light source for illumination according to the present invention. It is arranged so as to be adjacent to the element.

FIG. 9 is an enlarged sectional view schematically showing a configuration example of a liquid crystal color display device using the illumination light source of the present invention. A liquid crystal substance 3 is provided between an upper substrate 33 and a lower substrate 35 which are arranged to face each other.
9 is sealed to form a liquid crystal cell 31, and a transparent pixel electrode 41 and a transparent common electrode 43 are provided on the lower substrate 35 and the upper substrate 33, respectively. Of course, the pixel electrode can be provided on the upper substrate and the common electrode can be provided on the lower substrate. 37 is a sealing material. And this liquid crystal cell 31
is sandwiched between a first polarizing plate 51 on the observation side and a second polarizing plate 53 having an absorption axis parallel to the absorption axis of the first polarizing plate 51, forming a twisted nematic (TN) type liquid crystal element 55. has been done. An illumination light source 11 of the present invention shown in FIG. 6 is disposed below the liquid crystal element 55. Light source 1 for lighting
A phosphor layer 21 is formed on the inner surface of the tube wall 13 adjacent to the liquid crystal cell 55 of 1.
), green (G), and blue (B).

Each pixel filter section 18a has a single color of R, G, and B.

A colored filter 18 in which 18b and 18c are formed in a mosaic shape is provided, and these pixel filters 18a
, 18 b and 18 c are formed to match the transparent electrodes.

As shown in FIG. 1O, when the illumination light source 11 is turned on, the phosphors (R:., G: 1m, B: m) of the phosphor layer 21 emit light in 83 colors of R, G, Light (→, →, →) is generated. These lights enter each pixel filter 18 of the colored filter 17, and red light (R light →) is output from the red pixel filter 18a (R), and green light (G light →) is output from the green pixel filter 18b (G). ) is the blue pixel filter 18c (B)
Blue light (B light -→) is transmitted from the illumination light g11, and a collection of light beams of R, IG, and B single colors is emitted and enters the liquid crystal element 55. Since the transparent pixel electrode 41 of the liquid crystal element 55 and each pixel filter 18 of the colored filter 17 correspond to each other, by applying a voltage corresponding to the color image signal to the transparent pixel electrode 41 using a thin film transistor (not shown) or the like, , the light passing through the liquid crystal element 55 can be controlled. The liquid crystal element 55 is constructed by arranging 90'-T N cells between parallel Nicols, and only the light that passes through the pixel filter corresponding to the pixel electrode 41 with the voltage ON and enters the liquid crystal element 55 is transmitted to the liquid crystal element 55. The light passes through the element 55 and is observed, and a full-color image is displayed. Figure 10 shows
This shows a state in which R light and G light are transmitted at a ratio of 2=1.

As already explained, the light incident on the colored filter 17 is a mixed fluorescence of R, G, and B unit colors generated in the phosphor layer 21, and has high brightness. In addition, white light has an energy distribution over the entire wavelength range centered on the visible range, and includes light in a wavelength range that does not substantially contribute to the color separation of the three primary colors R, G, and B. , B, almost all of the light energy is used for color separation, making it possible to obtain bright images with high energy efficiency. Furthermore, this RlG and B fluorescence is R and G, respectively.
, the light obtained by passing through the B pixel filter is
As shown in Figures 3 to 5, the product of the fluorescence wavelength characteristics and the wavelength characteristics of the pixel filter produces light with a sharp rise and small half-width, making it more monochromatic, resulting in a clear image. It will be done. In this case as well, since the fluorescence from the phosphor has a large amount of light energy, a bright image can be obtained even if it is transmitted through a color filter. Furthermore, although the emission brightness and emission color purity of R2O and B differ when the phosphors emit light alone, these can be adjusted using R, G, and B colored filters, and images with good color reproducibility can be realized. I can do it.

FIG. 11 shows the use of the illumination light source 11 of FIG. 1 in which the phosphor layer formed on the tube wall is also formed in the shape of a pixel.
FIG. 12 is a cross-sectional view showing an example of the configuration of a liquid crystal color display device in which pixel filters and pixel electrodes are all aligned, and FIG. 12 is an explanatory diagram similar to FIG. 10. The phosphor layer 21 consists of a phosphor pixel section 22, and each phosphor pixel section 22a, 22b, 22c includes a red phosphor R (6), a green phosphor G (ffl), and a blue phosphor B ( ).

Compared to the cases shown in FIGS. 9 and 10, more phosphor R, G, or B can be included in the phosphor pixel section 22, so that the phosphor can be observed through each pixel section. R
, G, and B light can be further increased, and a clearer image can be obtained.

As the TN type liquid crystal element, the same type as those conventionally known can be used. Transparent supports such as glass, polyester, polysulfone, polycarbonate, and plastics such as polypropylene are used as the upper and lower substrates of the TN type liquid crystal cell. The pixel electrode and common electrode on this transparent substrate are formed by, for example, a PVD method such as vacuum evaporation or sputtering, or a CVD method.
A transparent conductive film such as ITO or NESA may be formed.

The pixel electrode is formed by patterning using a photoetching method or the like, and an electrode corresponding to a color image signal is applied using a thin film transistor or the like, and a full color image is displayed by active matrix driving.

For example, the following liquid crystal substances are used, and by aligning the upper and lower substrates, the liquid crystal substances are arranged between the substrates so that the molecular arrangement is twisted by 90'.

(1) Liquid crystal compound of P-alkylbenzylidene-p'-cyanoaniline and 2-alkoxybenzylidene-P'-cyanoaniline (2) Phenylbenzoate-based liquid crystal compound X and Y are thylkyl group, alkoxy group, etc.

(3) Liquid crystal compound of cyanobiphenyl type and cyanoterphenyl type I
X is CnH2n+1 (n is 3 to 10) CHH
2H416 (n is 3 to 10) (4) Cyclohexylcarboxylic acid ester liquid crystal compound (5) Phenylcyclohexane and biphenylcyclohexane liquid crystal compound (6) Phenylpyridine and phenyldioxane liquid crystal compound (7 ) A mixture of the above liquid crystal compounds or a mixture of the above liquid crystal compound and a cholesteric compound.

Furthermore, liquid crystal elements other than the TN type liquid crystal element can also be used as long as they are used as optical switching elements; for example, a guest-host type liquid crystal element can also be used.

The case where full-color display is performed using transparent pixel electrodes and active matrix driving using TPT or the like has been described above, but other electrode configurations and single-color or multi-color display other than full-color display are also possible.

For example, a full-color image can be displayed by providing electrodes in the form of stripes in the X-Y direction, pixel filters or further providing pixel phosphors at the intersections thereof, and multiplex driving. The arrangement of the liquid crystal cell, phosphor layer, colored filter, etc. is as already described. Multiplex driving has a limit in increasing the duty due to crosstalk effects, and from this point of view, the above-mentioned active matrix driving is more advantageous.

In addition, color display is performed using an arbitrary single colored filter and a phosphor layer that emits fluorescence with overlapping characteristic wavelength regions, without using a colored filter composed of R, G, and B pixel filter sections. You can also do that. For example, a plurality of figure 8-shaped segment electrodes are used, and portions corresponding to the individual segment electrodes are provided with colored filters and phosphor layers of arbitrary colors, so that a single color display of red can be performed. Of course, colored filters and phosphor layers of multiple colors are arranged corresponding to each segment electrode,
It is also possible to display multiple colors, such as changing the color depending on the number of digits.

Effects of the Invention According to the illumination light source of the present invention, by further transmitting the light emitted from the phosphor through a colored filter, it is possible to irradiate clear chromatic light with large light energy. Furthermore, since the phosphor layer and colored filter are formed on the tube wall, the tube can be made thinner.

Further, the illumination light source of the present invention is useful as a light source for color display, for example, if a liquid crystal element is combined as a switching element.

A bright and clear color display can be realized, and the entire device can be made thinner.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the illumination light source of the present invention, and FIG. 2 is a partially cutaway perspective view. FIG. 3, FIG. 4, and FIG. 5 are diagrams for explaining the color illumination characteristics of the illumination light source of the present invention. FIGS. 6, 7, and 8 are cross-sectional views showing other embodiments of the present invention. FIG. 9 is a sectional view showing a configuration example of a color liquid crystal display device using the illumination light source of the present invention, and FIG. 10 is a diagram for explaining a color display mechanism using the device. FIG. 11 is a sectional view showing a configuration example of a color liquid crystal display device using the illumination light source of the present invention, and FIG. 12 is a diagram for explaining a color display mechanism using the device.

Claims (1)

[Claims] 1. A phosphor layer containing a phosphor that emits colored light and a colored filter that transmits light from the phosphor layer are formed on the tube wall, and an electromagnetic wave radiation source capable of causing the phosphor to emit light is provided inside the tube wall. A light source for illumination, comprising: