JPS63220113A - Projecting device - Google Patents

Abstract

PURPOSE:To display an arbitrary image, and to execute a projection of this display image by controlling a temperature of a medium, varying a scattered state of light and the transmissivity of light, and controlling a temperature distribution of the medium. CONSTITUTION:A voltage is applied to all electrodes 4, 5 and the whole surface of an image display plate 11 is heated until it becomes a temperature exceeding a boundary value of a medium 9, and thereafter, when it is cooled slowly, as for the medium 9, its optical transmissivity becomes about 80%, and a display panel 1 becomes a transmission state. Subsequently, when a voltage is applied to the electrodes 4, 5 to match a shape of the formed pattern, and the part of the medium which becomes an intersection of the electrodes 4, 5 is heated, the optical transmissivity of the medium 9 of the heated part drops to about 10%, and the display panel 1 becomes a light cut-off state. Immediately thereafter, heat of the heated part is radiated quickly into the air, and absorbed by a heat absorbing member 10, therefore, the part concerned is quenched. Accordingly, from a characteristic of the medium 9, the optical transmittivity of a pattern formed part is maintained in about 10%. In such a way, an arbitrary pattern is formed in the display panel 1, and an image can be projected from a projecting part 15.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a projection device.

2. Description of the Related Art Conventionally, there has been a projection device that projects an image written on a document onto a screen, but this is inconvenient because the document must be prepared in advance. For this reason, a liquid crystal panel is placed in the optical path from the light source to the light projector, and a desired image is displayed on the liquid crystal panel on the spot by selecting the electrodes of this liquid crystal panel and applying a voltage. Some devices are designed to illuminate this liquid crystal panel with a light source and project an image on the liquid crystal panel onto a screen from a light projector.

An object of the present invention is to provide a projection device whose principle is completely different from that of a conventional display device using a liquid crystal panel.

Means for Solving the Problems An image display board made of a medium whose light scattering state and light transmittance change with temperature changes is provided in the optical path from the light source to the light-transmitting section.

Therefore, by controlling the temperature of the medium, the light scattering state and light transmittance are changed, and by controlling the temperature distribution of the medium, an arbitrary image can be displayed on the image display board, and this image can be The image on the display board is projected from a light projecting section.

Embodiment 2 A first embodiment of the invention will be described with reference to FIGS. 1 to 6. Reference numeral 1 shown in FIGS. 1 and 2 is a rectangular plate-shaped display panel. As shown in FIG. 3, this display panel 1 is made up of a medium 9 whose light transmittance changes with heat and a heat absorbing member 10.

This medium 9 is made by melting a vinylidene fluoride copolymer and an acrylic ester copolymer in a ketone, ester, or cyclic ether solvent, and is applied to one surface of the heat absorbing member 10.
It is coated with a thickness of about 00 μm. On the other hand, the heat absorbing member 10 is formed of a translucent member with excellent heat absorption rate.

Transparent substrates 2 and 3 are provided on the front and back sides of the display panel l.
are joined. A large number of band-shaped transparent electrodes 4 are formed in parallel on the back surface of the front transparent substrate 2.
A large number of strip-shaped electrodes 5 are formed in parallel in a direction perpendicular to the transparent electrode 4 on the front surface of the transparent electrode 4 . These electrodes 5 are formed of metal foil such as aluminum and serve also as a reflective surface. Further, on the front surface of the front transparent substrate 2, a transmission type condensing Fresnel lens 7, which has a large number of annular grooves 6 arranged concentrically, is integrally formed. The distance between the transparent substrates 2 and 3 is determined by a rectangular spacer 8 surrounding the display panel 1ti.

The image display board 11 configured in this way is housed at the back of the housing 12 as shown in FIG. An imaging lens 15 is held in the housing 12. A screen 16 is provided in front of the housing 12.

In such a configuration, the relationship between the temperature of the medium 9 and the light transmittance will be explained based on the graphs in FIGS. 4(a) and 4(b). FIG. 4(a) shows the characteristics when slowly cooled after heating, and FIG. 4(b) shows the characteristics when rapidly cooled after heating. As is clear from these grabs, when the medium 9 is heated,
The light transmittance, which was initially about 80%, decreases to about 10% with a boundary value around 180 degrees Celsius. At this time, the medium 9 becomes cloudy. On the other hand, when the medium 9 that has been heated once beyond the boundary value is cooled, the light transmittance returns to about 80% when it is gradually cooled, and the light transmittance is maintained at about 10% when it is rapidly cooled.

Therefore, by utilizing the characteristics of the medium 9 as described above, the electrode 4
, 5 is selected and a voltage is applied, dots are formed on the image display board 11 and an image is displayed. The process will be explained next. First, a voltage is applied to all electrodes 4.degree. 5 to heat the entire surface of the image display panel 11 until the temperature exceeds the boundary value of the medium 9, and then the temperature is slowly cooled. As a result, the entire medium 9 has a light transmittance of about 80%, and the display panel 1 is in a transmitting state.Next, by applying a voltage to the electrodes 4.5 in accordance with the shape of the formed pattern, the electrodes 4.5. When the part of the medium 9 that is the intersection of 5 is heated, the medium 9 of the heated part
The light transmittance decreases to about 10%, and the display panel 1 enters a light-blocking state. Immediately thereafter, the heat of the heated portion is rapidly radiated into the air and absorbed by the heat absorbing member 10, so that the portion is rapidly cooled. Therefore, depending on the characteristics of the medium 9, the light transmittance of the pattern forming portion is maintained at about 10%. In this way, any pattern can be formed on the display panel 1.

At this time, due to the presence of the heat absorbing member 10, the heated portion is sufficiently rapidly cooled only by natural heat radiation.

This allows pattern formation on the display panel 1.

This can be achieved by simply heating the pattern portion to be formed after the display panel 1 is brought into a fully transparent state.

If the display panel 1 required for pattern formation is heated to a temperature exceeding the boundary value of the medium 9 and then slowly cooled, the display panel 1 will recover its fully transparent state again.

Due to such reversibility of the display panel 1, the same display panel 1 can be used repeatedly.

Next, a modification of this display panel 1 is shown in FIG. In this structure, a medium 9 is formed in the form of a film on a transparent plate 17, and a heat absorbing member 10 is further formed in the form of a film on this medium 9. For example, glass is used as the transparent plate 17, but plastics such as acrylic may also be used. In this case, it is necessary to interpose a chemical insulating material between the medium 9 and the transparent plate 17 in order to prevent the plastic from reacting with the medium 9 and affecting the light transmittance. With such a structure, the medium 9 is formed on the transparent plate 17, so that the medium 9 can be formed extremely thin. For example, it is also possible to set the thickness to about 1 μm. In this case, the light transmittance of the medium 9 is
It will be about 90% to 50%. About 90% is when the transmittance is increased, and about 50% is when the transmittance is decreased. In this way, by varying the thickness of the medium 9, the range of variation in light transmittance can be freely set.

An image is displayed on the display panel 1 in the second manner. When the display panel 1 is illuminated with light from the light source 13, the condenser lens 14 diffuses the illumination light from the light source 13. This illumination light is efficiently focused by the condensing Fresnel lens 7 and irradiated onto the display panel 1, reflected by the electrode 5, transmitted through the display panel 1 again, and then passed through the condensing Fresnel lens 7 to the imaging lens 13. The light is focused so as to illuminate the entire aperture of the light and projected onto the screen 14.

In this way, an image is projected. The condensing Fresnel lens 7 condenses the illumination light from the light source 13 just in front of the display panel 1 and irradiates the entire surface of the display panel 1, and also collects the light rays reflected by the electrodes 5. It becomes possible to condense the light so that it irradiates the entire aperture of the imaging lens 13, and the electrode 5 serving as a reflective surface reflects the illumination light efficiently. Furthermore, the electrode 5
is in close contact with the back surface of the display panel 1, so that the reflected image will not shift. Therefore, even if a display panel 1 with a large area and a large number of small dots is used, the resolution of the projected image can be improved. Moreover, since the illumination light passes through the display panel l twice, the contrast of the image can be increased and the outline can be made clear. Furthermore, by using the electrode 5 as a reflective surface, there is no need to separately provide a reflective plate and adjust its installation position, and the condensing Fresnel lens 7 is also formed integrally with the transparent substrate 2, so it does not need to be provided separately. There is no need to adjust the mounting position.

Further, the condensing Fresnel lens 7 is located just in front of the display panel 1, and by arranging the light source 13 and the imaging lens 15 in front of it, the optical path length can be shortened and space can be saved.

Note that since the electrode 5 does not transmit light, an opaque substrate may be used in place of the transparent substrate 3 on the back surface.

Further, although the electrodes 4 and 5 to which a voltage is applied are used to heat the display panel 1, the medium 9 may be heated by irradiating a laser beam or the like.

Next, a second embodiment of the present invention will be described based on FIG. 7. Parts that are the same as those in the embodiment described above will be designated by the same reference numerals, and the description thereof will be omitted (the same applies hereinafter). This embodiment uses an image display board 20 in which a reflective surface 18 made of metal foil is formed on the entire back surface of a transparent substrate 3, and a transparent electrode 19 is formed on the front surface of this transparent substrate 3.

Therefore, the reflective surface 1 formed on the entire back surface of the transparent substrate 3
By reflecting the illumination light by the electrodes 8, the reflection efficiency can be further improved compared to the case where the electrodes 5 arranged with even a slight gap are used as reflection surfaces as in the previous embodiment.

As a modification, the back surface of the reflective surface 18 may be covered with a protective layer 21 as shown in FIG.

This protective layer 21 is formed, for example, from the same material as the transparent substrate 3 by means such as double molding.

Furthermore, a third embodiment of the present invention will be described based on FIG. 9. In this embodiment, a plurality of annular grooves are formed on the back surface of the back transparent substrate 3 and a metal film 22 is formed thereon to form a reflective Fresnel lens 23 as a reflective surface. Protective layer 21 covers the surface of lens 23
This uses an image display board 24 covered with. This protective layer 21 is formed, for example, by double molding of the same material as the transparent substrate 3, but this protective layer 21 can also be omitted.

Therefore, the reflective Fresnel lens 23 reflects the illumination light from the light source 13 and focuses the reflected light so that it irradiates the entire aperture of the imaging lens 15 . In this way, one member can reflect and collect light at the same time,
The structure can be further simplified.

Next, we will show an embodiment that does not include a condensing Fresnel lens but does include a reflective surface.

FIG. 10 shows a fourth embodiment of the present invention, in which a transparent substrate 2 having a transparent electrode 4 is disposed on the front side of a display panel 1, and a metal foil having a reflective surface function is placed on the back side of the display panel 1. An image display plate 25 is formed by disposing a transparent substrate 3 on which electrodes 5 are formed. That is, in the image display plate 11 shown in FIGS. 1 and 2, the formation of the condensing Fresnel lens 7 is omitted, and the reflective action of the electrode 5 is left.

FIG. 11 shows a fifth embodiment of the present invention, in which a transparent substrate 2 on which a transparent electrode 4 is formed is bonded to the front side of a display panel 1, and a transparent substrate 3 on which a transparent electrode 19 is formed on the back side.
An image display board 26 is formed by bonding the transparent substrate 3 and forming a reflective surface 18 on the back surface of the transparent substrate 3.

Note that, as shown in FIG. 12, the reflective surface 18 is covered with a protective layer 21.
It may be covered by

Effects of the Invention Since the present invention is configured as described above, the light scattering state and light transmittance are changed by controlling the temperature of the medium, thereby controlling the temperature distribution of the medium to create an arbitrary image. The image can be displayed on an image display board, and the image on the image display board can be projected by projecting light from a light projecting unit. Also, the energy for displaying the image can be selected from sources other than electric power. It has effects such as being able to.

[Brief explanation of the drawing]

1 to 6 show a first embodiment of the present invention, in which FIG. 1 is a vertical side view, FIG. 2 is a plan view, and FIG. 3 is an enlarged view of the structure of the display panel. Fig. 4(a) is a graph showing the change in light transmittance of the medium when it is slowly cooled after heating, and Fig. 4(b) is a graph showing the change in the light transmittance of the medium when it is rapidly cooled after heating. Graph showing the changes; FIG. 5 is a partially enlarged vertical side view showing the structure of another display panel; FIG. 6 is a vertical side view showing the image projection state in a reduced size; FIG. 7 is a graph showing the structure of the present invention. Vertical side view of the image display board showing the second embodiment, No. 8
The figure is a longitudinal sectional side view of an image display board showing a modification thereof, FIG. 9 is a longitudinal sectional side view of an image display board showing a third embodiment of the invention, and FIG. 10 is a longitudinal sectional side view of an image display board showing a third embodiment of the invention. FIGS. 11 and 12 are vertical side views of an image display board showing a fifth embodiment of the present invention. 9... Medium, 11... Image display board, 13... Light source, 15... Imaging lens (light projection part), 20, 24, 25
゜26...Image display board

Claims (1)

[Claims] A projection device characterized in that an image display plate formed of a medium whose light scattering state and light transmittance change depending on temperature changes is provided in an optical path from a light source to a light-transmitting part.