JPH0469642A - Projection type display device - Google Patents

Abstract

PURPOSE:To enhance light emission efficiency and to decrease a calorific value by generating electrons by an electron beam generating means and using the light emitted by a phosphor layer by the collision of the accelerated electron beams as projecting light. CONSTITUTION:A voltage which is negative with respect to a cathode 309 is impressed to a grid 310. The electron beam 304 is shot toward the phosphor layer 302 if the voltage of the grid 310 is approximated to the potential of the cathode 309 by applying the prescribed current to the heater 308 and heating the cathode 309. This electron beam 304 is made into a non-converging beam having a prescribed spread theta and the entire surface of the phosphor layer 302 is irradiated with this beam so that the phosphor layer 302 emits light to the light emitting colors corresponding to the phosphors of respective color light source tubes 300B, 300G, 300R. The respective color light rays transmit a polarizing plate 250 and are subjected to modulation in light intensity by a blue light valve 215, a green light valve 216 and a red light valve 217. These light rays transmit the 2nd sheet of the polarizing plate 220. The light rays are thereafter synthesized by a dichroic prism 230 and the projected onto a screen 233 by a projecting lens 231.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a projection type display device that irradiates an optical image formed on a light valve with irradiation light and projects it onto a screen using a projection lens. , especially regarding its light source.

[Prior Art] Conventionally, as a device for displaying images on a large screen, an optical image is formed in a relatively small light valve according to a video signal as a change in optical characteristics, and this optical image is illuminated with illumination light. Projection type display devices that enlarge and project images onto a screen using a projection lens are well known.

For example, as a conventional projection display device,
There was one shown in Publication No. 4286. FIG. 8 is a block diagram showing a conventional projection display device.

In the figure, (20+) is a halogen lamp light source, (2I
I) is a blue reflective dichroic mirror, and (212) is a green reflective dichroic mirror, each of which reflects only the color of the corresponding wavelength. (213) is a total reflection mirror,
Further, (215) is a blue light valve, (216) is a green light bulb 1~, and (2171 is a red light valve), which form an optical image of the corresponding color. (220), f
250) is a polarizing plate, (2301 is a gicroic brism: synthesizes three-color optical images. (231) is a projection lens, (233) is a screen, (270) is a transparent aluminum nitride for cooling. It is a sintered body.

The operation will be explained below.

The light emitted from the halogen lamp (20+1) is separated into blue, green, and red primary color lights by a blue reflective dichroic mirror (2+11) and a green reflective dichroic mirror (212). Each color light is transmitted through a polarizing plate (250). hand,
The light intensity is modulated by the blue light bulb (215), the green light bulb (2+61'), and the red light bulb (217), and is transmitted through two polarizing plates (220).After this, the dichroic prism ( 2301 and projected onto the screen by the projection lens f231).
The image is projected onto the image.

A polarizing plate (2501) and a blue light bulb (21
5), an aluminum nitride sintered cooling plate (
2701, and is cooled by blowing air from a fan (not shown) placed at the bottom. Therefore, the polarizing plate (2501
The heat generated is quickly removed by the sintered body cooling plate (2701).

[Problems to be Solved by the Invention] Conventional projection display devices are configured as shown below, and require a cooling plate for heat dissipation. A fan was required to dissipate the emitted heat to the outside of the device. This poses a problem in that the device becomes large. Furthermore, since most of the power supplied to the light source is converted to heat,
There was also the problem that the power consumption was high.

This invention was made in order to solve the problems mentioned in 5. It is possible to realize a compact device that does not require a cooling plate or a heat dissipation fan, and also to obtain a projection type display device with low power consumption. purpose.

[Means for Solving the Problems] A projection type display device according to the invention of claim 1 of the present invention includes, as a light source, an electron beam generating means for generating an electron beam, and an electron beam generated by the electron beam generating means. It is characterized by having a phosphor layer that emits light when excited.

Furthermore, a projection type display device according to a second aspect of the present invention is characterized in that, in addition to the first aspect of the invention, a light source and a light valve are bonded together with a transparent adhesive.

[Function] The projection type display device according to the present invention generates electrons with an electron beam generating means, and uses the light emitted by the phosphor layer due to the collision of the accelerated electron beam as the projection light, so it has good luminous efficiency and a low calorific value. It is possible to realize a projection type display device with a small amount of noise.

[Example] An example of the present invention will be described below with reference to FIGS. 1 and 2. FIG. 1 is a configuration diagram showing a three-panel valve type projection display device according to an embodiment of the present invention, and the same or corresponding parts as in FIG. 8 are denoted by the same reference numerals.
Explanation will be omitted.

In Figure 1, (300B) is a blue light source tube; (300B) is a blue light source tube;
G) is a green light source tube, and (30OR) is a red light source tube.

Figure 2 shows each color light source tube (300131, (3[1[IG
1, (300R);
FIG. In Figure 2, (30
Reference numeral 11 denotes, for example, a cylindrical vacuum envelope for maintaining a vacuum inside the light source tube. This vacuum envelope (301) has a face glass (303) on which a phosphor layer (3021) is adhered on the inner surface at one end, and a non-focused electron beam (302) covering the entire surface of the phosphor layer (302) at the other end. []4) An electron gun (305) for irradiation, a terminal (306) for applying the required voltage to each part of the electron gun (3051), and a vacuum envelope (
It has a stem portion (307) that closes 3011.

The electron gun (305) has a heater (308) and a cathode (309).
), and a grid (31O). Further, the phosphor layer (302) may include, for example, a blue light source tube (300B).
) Deba ZnS:Ag, CI, green light source tube (300G)
So ZnS:Au, Cu, AI, red light source tube (3D
OR) uses Y2O2S:EIJ3+,
The surface area of each is large enough to cover the effective display surface of each color light bulb.

The operation will be explained below. First, in Figure 2,
A negative voltage is applied to the grid (3101) with respect to the cathode (309). At the same time, a predetermined current is applied to the heater (3[11i) to heat the cathode (309) and the grid i3+0
When the voltage of 1 is brought close to the potential of negative 1i1ii (309), an electron beam (304) is emitted from the cathode (309) toward the phosphor layer (302). This electron beam (304) is directed directly through the hole (311) provided in the center of the grid (310). Child, grid (310) and cathode f3
Depending on various conditions such as the distance between the phosphor layer (302) and the anode voltage, the beam becomes an unfocused beam with a predetermined spread (O) and illuminates the entire surface of the phosphor layer (3021). (300rl), (300G), (30
0R) to emit light in a color corresponding to the phosphor.

In Figure 3, the horizontal axis is wavelength (nm), and the vertical axis is intensity (arbitrary units).
It is a characteristic diagram showing the emission spectrum emitted from the light source tube (300). The emission spectra from the blue light source tube (300B), green light source tube (300G), and red light source tube (300R) are (400B), f400G), respectively.
Highly pure blue, green, and red primary color light as shown in (400R) is emitted. Each color light is connected to the polarizing plate (25
0), blue light bulb (2151, green light bulb (2+6), red light bulb (2+7)
The light intensity is modulated by two polarizing plates (220
). After this, dichroic prism (23
0) and projected onto the screen (233) by the projection lens (2311).

Here, the luminous efficiency of the phosphor (302) due to electron beam excitation is determined by the Z of the phosphor used in the green light source tube (300B).
nS: 5001 in Au, Cu, AI. 301. of halogen lamps including m/W. It is more than 10 times higher than m/W. Therefore, the amount of heat generated from the light source is extremely small, and the conventional cooling plate and heat dissipation fan are not needed, so a compact projection display device with low power consumption can be realized.

In addition, as another example, in order to increase the luminous efficiency of each color light source tube (3001), the middle part of the face glass (303) is made thicker than the peripheral part to give a convex lens effect, as shown in Fig. 4. , a dielectric multilayer film (320) is provided between the face glass (303) and the phosphor layer (3021), or an aluminum back (321) is provided inside the phosphor layer (302).
You may also apply With this configuration, it is also possible to focus the emitted light in the normal direction (in the direction of the arrow) of the surface of the face glass (3031). This is also possible by forming a

FIG. 5 is a block diagram showing a +11 temporary light valve type projection display device according to still another embodiment of the present invention. In the figure, (300W) is a white light source tube whose configuration is the same as that shown in FIG. :F, t+''+ is used. Also, the emitted light includes primary color light of blue, green, and red, which has a spectrum as shown in Figure 3, for example. In addition, (280) is a light valve (color filter layer consisting of a combination of blue, green, and red formed in a mosaic shape for every 2+81 pixels).

In Figure 5, white light containing primary color lights of blue, green, and red emitted from a white light source tube (300W) is transmitted through a polarizing plate (250W).
1, the light is intensity-modulated by a light valve (218) equipped with a color filter (2801), and after passing through two rJ polarizing plates (220), it is projected onto a screen (233) by a projection lens (231). be done.

In addition, in the embodiment described in Section 2, each color light source tube (300B) (3
00G), (300R), f300Wl and the first polarizing plate (2501) on the iU surface of the light valve are installed at a distance, but as shown in Figure 6, each color light source tube (
300) face glass (303) and the first polarizing plate (
250) with a transparent adhesive (290) and eliminate the air layer, it is possible to reduce the reflection of light when it enters the polarizing plate and increase the efficiency of using the light emitted from the light source. . In this embodiment, the transparent adhesive (290) is, for example, a two-component addition reaction type silicone RTV resin (KE1603A/n manufactured by Shin-Etsu Chemical Co., Ltd.).

Furthermore, as shown in Fig. 7, a cooling section consisting of a transparent container (401) filled with a cooling liquid (4021) such as ethylene glycol or silicone oil is installed on the front of the face glass (303) in front of the light source tube (3001). (400) may be provided and bonded to the first polarizing plate (250) on the light valve (21711iij plane) with a transparent adhesive (290) without an air space. With this configuration, the temperature of the phosphor layer can be reduced. Since it is possible to keep the temperature rise low, it is possible to increase the luminous efficiency of the phosphor and extend its life.In addition, it is also possible to prevent heat conduction to the light valve (2171).
jJ Noh yells. In addition, if the thickness of the cooling part (4001) filled with cooling liquid (4021) is made thicker than the peripheral part to give a convex lens effect, and the light valve (217) is installed away from the cooling part (400), , the emitted light can be made to enter the light valve (217i) as parallel rays, and it is also possible to improve the efficiency of light utilization.

Further, in the above embodiments, a transmission type light valve (217) was used as an example, but a reflection type light valve may also be used. In this case, if the configuration is such that the light from the light source is irradiated onto the light bulbs 1 to 2 as parallel rays through a lens, and the reflected light of the optical image of light bulb 2 is enlarged and projected onto the screen through the projection lens, the above can be achieved. Same effect.

As described above, if this invention is applied to a three-plate light valve projection display device, there is no need for an optical system such as a dichroic mirror for separating white light into the three primary color lights of blue, green, and red. Therefore, the effect of reducing the size of the device is significant.

In addition, in this invention, since the light emitting part can be made planar, the distance between the light emitting part and the light bulb is shortened, and most of the emitted light is incident as light with a similar intensity over the entire surface of the bulb. Second, it is possible to remove the reflective layer such as the air layer between the light emitting part and the light valve, making it possible to greatly increase the efficiency of light use.

Furthermore, if the cooling part (400) injected with transparent cooling liquid is provided in close contact with the front surface of the planar light emitting part, the temperature rise of the light emitting part can be suppressed to a low level, and the luminous efficiency of the phosphor can be increased. Not only can it be used for a long time, it also prevents heat conduction to the light bulb and has the effect of suppressing the rise in temperature of the light bulb.

[Effect of the invention] As shown in the following, according to the invention of claim 1 of this invention,
Equipped with a lens, a light source, and a light bulb that forms an optical image in response to a video signal, the light emitted from the light source irradiates the light bulb to form an optical image, and this optical image is projected onto a screen through the lens. In the projection type display device, the light source is equipped with an electron beam generating means that generates an electron beam and a phosphor layer that emits light when excited by the electron beam generated by the electron beam generating means. The light emitting efficiency is very high, the amount of heat generated from the light source is very small, and a cooling plate and a heat dissipation fan are not required, so it is possible to realize a compact projection display device with low power consumption.

Furthermore, according to the invention of claim 2 of this invention, claim 1
In addition to the above invention, the light source and light valve are bonded together with a transparent adhesive, which has the effect of greatly increasing light utilization efficiency.

[Brief explanation of the drawing]

1 is a block diagram showing a projection type display device according to an embodiment of the present invention, FIG. 2 is a sectional view showing a cross section of each color light source tube in FIG. 1, and FIG. 3 is a sectional view showing a cross section of each color light source tube in FIG. 1. A characteristic diagram showing emission spectra of blue, green, and red; FIG. 4 is a cross-sectional view of each color light source tube in a projection display device according to another embodiment of the invention; FIG. 5 is a further embodiment of the invention. FIGS. 6 and 7 are explanatory diagrams according to still other embodiments of the present invention, and FIG. 8 is a configuration diagram showing a conventional projection display device. . (2+5+, (2161, (2171, (2181・
・Light bulb, +220) , (250) ・・
・Polarizing plate, (230) ... Dichroic prism, (231) ... Projection lens, (233) ...
・Screen, (300), (300111, (3
00G), +30OR), (300Wl ・
... Light source tube, (302) ... Phosphor layer, (305)
...Electron gun. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A lens, a light source, and a light valve on which an optical image is formed according to a video signal, the light emitted from the light source is irradiated onto the light valve to form an optical image, and this optical image is transferred to the lens. A projection type display device for projecting images onto a screen through a light source, characterized in that the light source includes an electron beam generating means for generating an electron beam, and a phosphor layer that emits light when excited by the electron beam generated by the electron beam generating means. A projection display device. (2) The projection type display device according to claim 1, wherein the light source and the light valve are bonded together with a transparent adhesive.