JPS6020104Y2 - thermal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal display device with high density and good contrast, and particularly to its display body.

A side view of this type of display device is shown in FIG.

In FIG. 1, 1 is a heat-sensitive display, 2 and 3 are heating elements, 4 is a cooler, 5 is a motor, 6a and 6b are pulleys, and 7 is an illuminator.

The heat-sensitive display body 1 is a flexible sheet such as a polyester film coated with a heat-sensitive material, and here it is in the form of an endless belt, and can be moved by a drive motor 5 via pulleys 6a and 6b.

As a heat-sensitive material, for example, Ag2HgI4 described in JP-A No. 50-57283. There are Cu2HgI4, etc., and specifically, there is a reversible temperature indicating material sold by Teika Sangyo under the trade name 1 Thermolabel from -K.

Figure 2 shows the relationship between temperature and color of the heat-sensitive material.

Heat-sensitive materials change color depending on temperature and are reversible;
There is a hysteresis characteristic in the color change characteristic.

As the temperature rises and falls, the state changes to a and A. b, B
The transition will occur in the following order.

When writing an image, the thermosensitive member is kept at temperature T2 and in state A.

Next, temporarily set only the writing part to T3 or higher, then T2
If it is maintained in the state B, there will be a difference in color between the written area and the non-written area.

If the display section is cooled below T, the image will be erased.

The writing of the image is performed by the heating element 2, the heating element 3 is used to maintain the temperature at T2, and the cooling for erasing the display is performed by the cooler 4.

FIG. 3 shows the reflectance-wavelength characteristics of the A state and the B state.

In FIG. 3, one possible method for increasing the contrast by optical means is to provide a bandpass filter in front of the display surface that transmits only the wavelength of Δλ1.

However, this case is effective when the reflectance R1 is relatively larger than the reflectance R2.

When the reflection ratio □ is sufficiently small compared to the reflectance R2, the filter characteristic is that at least Δ input is transmitted, and Δ input is transmitted.

It is necessary to have the property of not transmitting. In this case Δλ2
Any transmission characteristics may be used in the region.

Filter 8 in FIG. 1 performs this function.

Filtering reduces display brightness, so
Supplement the brightness by lighting from outside.

It is necessary to use the illuminator 7 as a means for this purpose.

Such a display device has the following drawbacks.

First, since the illuminator 7 is placed between the display section and the filter 8, the depth from the filter 8 is too deep, making it difficult to see the display surface.

Second, the device becomes larger for the same reason.

When a specific location on the display surface is shown in FIG. 3, the filter 8
This must be done from outside, and the accuracy of the correspondence is lost.

In the present invention, by integrating a thin film having the function of the filter 8 with the display body, it is possible to realize miniaturization of the device and ease of viewing the display.

FIG. 4 is a diagram illustrating an example of a heat sensitive body display used in the present invention.

9 is a filter thin film, 10 is a heat-sensitive material layer, and 11 is a base material layer.

The filter thin film 9 has a function of transmitting light in the wavelength range Δλ□ and not transmitting light in the wavelength range Δλ3, like the filter 8 in FIG. 1, and also serves to protect the heat-sensitive material layer 10.

As the filter thin film 9, gelatin filter film,
Dyed cellophane film, dyed acrylic film, etc. are suitable.

As is clear from the above explanation, according to the present invention, since the thin film directly attached to the heat-sensitive display has a filtering effect, it is possible to increase the contrast without making the display surface difficult to see. have

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a general thermal display device, Fig. 2 is an explanatory diagram showing the relationship between the temperature and color of the heat-sensitive material, Fig. 3 is an explanatory diagram showing the relationship between the wavelength and reflectance of the heat-sensitive material, and Fig. 4 is an explanatory diagram showing the relationship between the wavelength and reflectance of the heat-sensitive material. The figure is a sectional view showing an example of a heat-sensitive display body used in the present invention. 1...Thermal display body, 2, 3...Heating element, 4...Cooler, 5...Motor, 6a
, 6b...Curved pulley, 7...Illuminator, 8...
...Optical filter, 9...Filter thin film, 1
0... Heat sensitive material layer, 11... Base material layer.

Claims (1)

[Scope of utility model registration request] In a thermal display device comprising a band-shaped endless thermal display, a means for driving the same, a heating body for writing a display, and a cooler for erasing a display, the thermal display has a base material layer and a base material layer. 1. A heat-sensitive display device comprising: a heat-sensitive material layer that changes color depending on the temperature; and a thin film that allows a specific wavelength to pass through the heat-sensitive material layer and does not allow other specific wavelengths to pass through the heat-sensitive material layer.