JPS5855405Y2 - Thermal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal display device equipped with means for detecting coordinate positions within a display surface.

A screen display device as a computer peripheral terminal may be used interactively, allowing deletion, insertion, and correction of displayed content such as characters and images. It becomes necessary to detect the above-mentioned corrected portions etc. as coordinate position information.

A CRT display device is known as a display device whose coordinate position can be easily detected.

The reason for this is that since the scanning lines forming the image information sequentially scan predetermined positions, the positions can be detected as optical information using a light pen.

However, in a thermal display device, since the above-mentioned means cannot be used, it is not easy to detect the coordinate position within the display surface.

In general, there are two methods for detecting the coordinate position within the display surface, such as a method that uses a pantograph to derive the coordinates from polar coordinates, and a method that uses a cursor on the coordinates and detects the coordinates from the intersection point. The portion is moved over a filter surface provided on the surface of the thermal display, which is not easy to operate, and the latter requires two cursors, making it expensive and complicated to operate.

Therefore, in a thermal display device using a heat-sensitive display material that requires a filter, it is an inexpensive method to provide the filter on the display surface with grid-like grid lines and indicate the row and column addresses at the ends of the filter. Although this can be considered as a means, it has the disadvantage that the provision of grid lines makes it difficult to see the filter surface and that as the display area becomes larger, indication errors are more likely to occur.

The purpose of the present invention is to solve such drawbacks, and to achieve this purpose, an optical filter formed of an isotropic medium, a piezoelectric element that applies mechanical vibration to the optical filter, and an optical filter are provided. A piezoelectric pen that detects mechanical vibration waves is used to accurately detect an image to be corrected as coordinate position information.

This will be explained below with reference to the drawings.

First, in order to make it easier to understand the present invention, the characteristics of the thermal display used as a display medium will be explained.

The heat-sensitive display material changes color depending on the temperature, is reversible, and has a hysteresis characteristic in temperature and color change characteristics as shown in Figure 1, and the state changes from a → A → as the temperature rises and falls. Transition occurs in the order of b→B→a.

When writing an image, the entire thermosensitive display body is kept at temperature Tc in state A, only the writing part is temporarily raised to temperature T2 or higher, and then kept at temperature Tc to become state B.
An image is obtained based on the difference in color between the written area and the non-written area.

Then, if the heat-sensitive display body is cooled to a temperature below T1, it becomes state a, and the written image can be erased.

Figure 2 shows the reflectance of the thermal display body in state A and state B.
Shows wavelength characteristics.

As a method of increasing the contrast between the written part and the non-written part by optical means, in order to cut the wavelength region where the reflectance of state A and state B does not change, for example, wavelengths of λ1 or less and wavelengths of 12 or more, optical means are used. A filter is placed in front of the display surface of the heat-sensitive display.

Also, if the reflectance R1 is low, it will transmit less than ^2, and 12
A filter that cuts the above may be used.

By using such a filter, a slight color difference can be converted into a large density difference in a nearly single color.

Next, one embodiment of the present invention will be described with reference to FIGS. 3 to 6. In FIG. 3, numeral 1 denotes a heat-sensitive display body having the above-mentioned characteristics, and is formed in the shape of an endless band.

Reference numeral 2 denotes a light transmitting type heating element disposed behind the display surface of the heat sensitive display element 1, and the light transmitting type heating element 2 is connected to a temperature controller 3.
The temperature is maintained at Tc.

Reference numeral 4 denotes a pulse motor drive circuit, and the thermal display 1 is moved in the direction of arrow A by a feed roller 6 connected to a motor 5 electrically controlled by the pulse motor drive circuit 4.

Reference numeral 7 denotes a thermal head having a configuration in which a plurality of dots of heating resistive elements are arranged horizontally in a row for writing an image on the thermal display body 1, and is driven by a thermal head driver circuit 8.

Reference numeral 9 denotes a plantain roller which is disposed at a position facing the thermal head 7 and is applied with pressure in order to efficiently write an image on the heat-sensitive display member 1. The plantain roller 9 is made of an elastic material and is used for feeding. Thermal display body 1 along with roller 6
is supported.

Since the image written on the thermal display body 1 is erased by cooling it to a temperature below T1, a cooler 10 incorporating an electronic cooling element is arranged so as to be in contact with a predetermined position of the thermal display body 1. There is.

Reference numeral 11 denotes a connector between the writing part and the non-writing part of the thermal display body 1.
This is an optical filter for improving the last and making the image easier to see.It is supported by a casing 12 that houses the thermal display 1 and the thermal head 7, etc., and is located in front of the display surface of the thermal display 1. .

On the back surface of this optical filter 11, as shown in FIG. A mechanical vibration wave is applied to the optical filter 11.

15 is a piezoelectric element drive circuit connected to the X-axis circumferential piezoelectric element 13, and 16 is a piezoelectric element drive circuit connected to the Y-axis circumferential piezoelectric element 14.

The piezoelectric pen 17 for picking up vibration waves on the optical filter 11 has a built-in pen tip 19 to which a piezoelectric element 1B is glued, as shown in FIG. It is connected.

Reference numeral 21 denotes a lamp disposed inside the heat-sensitive display body 1, which is used to compensate for the decrease in the amount of light on the display surface due to the optical filter 11, and is used to correct uneven brightness on the display surface of the heat-sensitive display body 1 and to provide illumination. Together with a reflecting plate 22 for increasing efficiency and a diffusing plate 23 for uniformizing brightness within the display surface, the written image on the display surface is made easier to see.

To explain the above-mentioned structure in more detail, the thermal display 1 uses a mercury iodide compound such as Ag2HgI4, and the display itself has a memory function.

As explained in FIG. 1, there are two concentration states, state A and state B, at temperature Tc.

In this example, the temperature Tc is 40'C, and the temperature T2 is 50'C.
At a temperature of 2°C, an image is written by coloring the writing part of the thermal display body 1 with the thermal head 7 at a temperature of 52°C, without raising the temperature of the part where writing is not done.
Thereafter, the entire display surface is maintained at 40° C. by the transparent heating element 2 to maintain the written image.

Erasing of the written image is carried out by moving the thermal display 1 by the feed roller 6 to move the written image to the position of the cooler 10, and lowering the temperature to 20 to 25 DEG C. with the cooler 10.

The background color of the heat-sensitive display member 1 made of Ag2Hg24 is yellow, and the image obtained by writing is orange.

If you look at this with your eyes, you will see the integrated value of light of about 51Q nm or more in the ground color part, and the integrated value of light of about 55Q nm or more in the image part, and both are areas on the long wavelength side. Since the difference is large and the difference is small, the contrast ratio is small and it becomes difficult to see.

Therefore, as previously described in FIG. 2, it is necessary to increase the contrast by cutting off the long wavelength side with a filter, and in this embodiment, a green optical filter 11 is used to improve this. .

When the optical filter 11 is used, the display surface becomes dark due to reflected light alone, so a lamp 21 is provided behind the display surface to provide a bright display.

Next, writing will be explained using characters as an example.

In FIG. 3, when the operator presses a character key on the kanji keyboard 24, a corresponding character code indicated by C0DE is generated and input into the control section 25.

The control section 25 accesses the character pattern memory 26, reads out the character pattern data corresponding to the character code, and stores the character pattern in the buffer memory 27 as an FMP→BUF signal.

This buffer memory 27 has a capacity to accommodate character patterns for one screen, and the character pattern data input by the control section 25 is stored at an address corresponding to the display position in the buffer memory 27.

Similarly, characters that are pressed one after another are stored in the buffer memory 27 one after another.

Next, when writing to the thermal display 1, the part corresponding to the corresponding line of the character pattern data in the buffer memory 27 is sent to the thermal head driver circuit 8 as a signal S under the instruction of the character line select circuit 28. and drives the thermal head 7 at a certain timing.

Then, the thermal head 7 writes one line on the thermal display 1.

When writing for one line is completed, the pulse motor 5 is driven at the timing according to the procedure to move the thermal display body 1 by one line in the direction of arrow A.

The pulse motor 5 is driven by the control section 25 via the pulse motor drive circuit 4.

Thereafter, each line is sequentially written one by one in the same manner, and the operation is completed to form a display surface of P rows with a line length W on the thermal display 1 as shown in FIG.

When erasing written characters, the thermal display 1 is moved in the direction of arrow A and the display surface on which the characters are written is brought into contact with the cooler 10, and the characters are sequentially erased and refreshed.

As mentioned above, the image of characters etc. written on the thermal display body 1 is
As mentioned above, visibility is improved by increasing the contrast through the optical filter 11.

This optical filter 11 is formed of a light-transmissive isotropic medium.

The thermal display 1 and the optical filter 11 are placed in close proximity to each other, so that the position of the image written on the thermal display 1 and the coordinate position on the surface of the optical filter 11 are different. By always having a one-to-one correspondence, the coordinate position information on the surface of the optical filter 11 can be considered to be equal to the information position of the image on the thermal display 1. By reading the coordinate position information above, the position information of the image on the thermal display 1 can be detected.

In this embodiment, in order to detect the coordinate position on the optical filter 11, first, the X-axis circumferential piezoelectric element 13 and the Y-axis partial piezoelectric element 14 bonded on the optical filter 11 are connected to each piezoelectric element drive circuit. 15 and 16 are alternately driven to apply mechanical vibration waves to the optical filter 11.

Next, by bringing the tip 19 at the tip of the piezoelectric pen 17 into contact with the desired position on the surface of the optical filter 11, the vibration waves from the X-axis and Y-axis on the optical filter 11 are transmitted to the piezoelectric element 18 inside the piezoelectric pen 17. Detect and convert into electrical signal,
This signal is sent to a counting circuit 20 connected to the piezoelectric element 1B.
The counting circuit 20 calculates the time interval during which the vibration waves generated by the X-axis circumferential piezoelectric element 13 and the Y-axis piezoelectric element 14 pass through the optical filter 11 between the piezoelectric elements 13 and 14 and the piezoelectric pen 17. , thereby obtaining information on the X and Y coordinates of the position of the piezoelectric pen 17 on the optical filter 11.

This information is used as an electrical signal to designate the corresponding address in the buffer memory 27 via the control unit 25, and by instructing deletion, correction, etc., using the kanji keyboard 24, the memory contents are changed and a refreshed thermal display is created. By rewriting the body 1, an image with only the specified position changed will be obtained.

As explained above, the present invention uses X-axis and Y-axis vibrations along the vertical and horizontal sides of an optical filter used for the purpose of improving the contrast of characters, images, etc. written on a thermal display. A piezoelectric element for wave generation is provided, and the resulting vibration waves are detected with a piezoelectric pen to obtain coordinate position information on the thermal display surface directly from the optical filter surface, making it easy to operate. Compared to other coordinate position detection means, it is possible to realize a thermal display device that is inexpensive, has high detection accuracy, and allows interactive correction of display contents.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the temperature and hysteresis characteristics in the color change characteristics of the heat-sensitive display used in the present invention, Figure 2 is a diagram showing the reflectance-wavelength characteristics of the heat-sensitive display at temperature Tc, and Figure 3 4 is a schematic configuration diagram showing an embodiment of the present invention, FIG. 4 is a front view of the filter section in FIG. 3, FIG. 5 is the constituent countries of the piezoelectric pen used in the present invention, and FIG. It is an example diagram of a written image. 1... Heat sensitive display body, 2... Light transmission type valve heating body,
5... Pulse motor, 6... Feed roller, 7... Thermal head, 9...
・Platen roller, 10... Cooler, 11...
...Optical filter, 12... Housing, 13
...X-axis circumferential piezoelectric element, 14...Y-axis piezoelectric element, 15, 16... piezoelectric element drive circuit,
17... Piezoelectric pen, 18... Piezoelectric element, 19... Pen tip, 20... Counting circuit, 21... Lamp, 22... ...Reflector, 23...Diffuser.

Claims (1)

[Scope of utility model registration request] An endless strip-shaped thermal display, a feed roller for rotationally moving the thermal display, a platen roller that supports the thermal display together with the feed roller, a thermal head for writing an image on the thermal display, and a display on the thermal display. A light-transmitting continuous heating element for keeping the surface warm; an optical film disposed close to the display surface of the heat-sensitive display to increase the contrast between the background color of the heat-sensitive display and the written image; and a display surface of the heat-sensitive display. In a thermal display device equipped with a lamp for illuminating from the back side of the display and a cooler for erasing an image written on the heat-sensitive display, an optical filter is formed of a light-transmissive isotropic medium, An X-axis piezoelectric element and a Y-axis piezoelectric element for applying mechanical vibration waves in the detection coordinate direction to the optical film are glued to an optical filter, and the tip of a piezoelectric pen for detecting the mechanical vibration waves is attached to the optical filter. 1. A thermal display device that detects a writing position of an image on a heat-sensitive display body as coordinate position information by bringing it into contact with a target filter surface.