JPS61261959A - Image reader - Google Patents

Abstract

PURPOSE:To obtain a signal of an appropriate image data irrespective of a reflection type by discriminating automatically whether an image source by a laser beam is the reflection type or the transmission type. CONSTITUTION:As for a laser beam of a laser diode 23, its intensity is modulated in accordance with a density of a picture element of a scan position of a source 1. It is converted to a signal St of an image data by a condenser lens 81 and a photodetector 82 which are positioned at the opposite side of a mirror of the image source 1, as a read means 80, and supplied to a switching circuit 86 through an amplifier 83. Also, the read means 80 is converted to a signal Sr of the image data by a mirror 28 and a photodetector 84, and supplied to a switching circuit 86 through an amplifier 85. The signal St and Sr are supplied to level detecting circuits 91, 92, respectively, each peak-to-peak level signal is fetched, both these signals are compared by a comparing circuit 93 and supplied to the switching circuit 86, and the signal of a larger level is fetched and becomes a signal of the image data.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an image capture device.

[Summary of the invention]

The present invention provides an image reading device that scans an image source with a laser beam to obtain an image data signal, by automatically determining whether the image source is a reflection type or a transmission type. Regardless of the type, an appropriate image data signal can be obtained.

BACKGROUND ART First, an example of a liquid crystal display device will be explained with reference to FIG. 2. This liquid crystal display device writes a display image on a liquid crystal cell by irradiating the liquid crystal cell with laser light.
This image is enlarged and projected onto a screen by a projection means and displayed.The image has two levels of density, white or black.

(10) shows the liquid crystal cell, and when it is irradiated with laser light, the laser light is converted into thermal energy and the irradiated area is heated, and this heating causes a phase transition in the liquid crystal. When the alignment state is disturbed and the laser beam is stopped, the irradiated area is rapidly cooled and the disordered alignment state of the liquid crystal remains as it is, so that the irradiated area becomes opaque.

For this reason, the liquid crystal cell (lO) is configured as shown in FIG. 3, for example. That is, in the same figure, (11
) is a liquid crystal filled in layers, with alignment layers (
12), (13) and transparent electrodes (14) (15)
) is provided. This electrode (14) is connected to the glass plate (1
6), and the electrode (15) is formed on a glass plate (1 day). The laser beam for writing is irradiated from the glass plate (16) side, and the projection light from the projection means is projected from the glass plate (18) side.

In this case, the liquid crystal (11) is a cyanobiphenyl liquid crystal, for example, a mixture of 40 mol% octylcyanobiphenyl and 60 mol% decylcyanobiphenyl, and when it absorbs laser light, Depending on the temperature, a phase transition occurs from smectic A phase to nematic phase to isotropic phase. Note that, for example, the phase transition temperature from the smectic A phase to the nematic phase is 44.8°C, and the phase transition temperature from the nematic phase to the isotropic phase is 45.2°C.

Furthermore, in the liquid crystal (11), for example, 1°3-
(1,4-dimethyl-7-itsuprobil azulenyl)
- Cyclobutenediylium is added to increase the efficiency of laser light absorption and transmission.

Further, as an example, the effective area of the liquid crystal cell (10) is hl
20 m x 20 cranes horizontally, resolution: &12,000 pixels x 2,000 pixels horizontally.

Furthermore, in FIG. 2, (20) indicates writing means using a laser beam. This writing means (20) turns on or off the laser light for each pixel according to the display data, and also directs the laser light to the liquid crystal cell (20).
11 to write an image on the cell (1).

That is, when display data is taken out from a microcomputer (70), which will be described later, this display data is supplied to a monostable multivibrator (21) and is made into a writing pulse with a pulse width of 2.5 μsec per pixel, and this pulse is supplied to the laser diode (23) through the drive circuit (22).

This diode (23) is, for example, a GaAlAs semiconductor laser, and outputs near-infrared light with an output of 30 mW and a wavelength of 780 nm.

Therefore, the diode (23) outputs laser light that is modulated on or off according to the display data, but this laser light is transmitted to the galvano mirror (24).
It is supplied to the liquid crystal cell (10) through →lens (25) →prism (26). Note that a cold filter (27) is provided on the back surface of the liquid crystal cell αφ to reflect laser light and improve thermal efficiency.

Further, in this case, the scanning means (30) scans the liquid crystal cell (10) with laser light. In other words, this scan includes rask scan or vector scan, and the microcomputer (70) transmits the X coordinate and Y coordinate of the scan position (laser beam irradiation position).
A digital horizontal address signal Ax and vertical address signal Ay specifying coordinates are taken out, and these signals Aχ,
Ay is supplied to the D/A converters (31) and (32) and converted into analog data before being sent to the drive circuit (33).
, (34) to a horizontal scanner (35) and a vertical scanner (36).
24) is driven horizontally and vertically to signal Ax.

A laser beam is irradiated to the coordinates of the liquid crystal cell (10) specified by A31. In addition, in this example, the liquid crystal cell αψ
Since the resolution is 2000 pixels vertically by 2000 pixels horizontally, the signals Ax and Ay are each 11 bits.

Furthermore, (41) shows an erase circuit, which is a microcomputer (
70), an alternating voltage ER of a predetermined level is extracted, and this voltage ER is applied to the electrode (10) of the liquid crystal cell (10).
14) and (15) for erasing.

However, there are two types of erasing: full erasing, which erases the entire surface of the cell (10), and partial erasing, which erases only a part of the cell (10).
These are performed as shown in the table below.

Note that in partial erasing, a low erasing voltage ER is supplied to the entire surface of the cell (10), and only the portion to be erased is irradiated with laser light.

Further, (42) indicates a temperature control circuit, which allows the liquid crystal cell (10) to maintain the first phase transition temperature of 44.8°C during steady state.
For example, the liquid crystal (11) is maintained (biased) at 43.3° C., which is 1.5° C. lower than that of 43.3° C., and therefore the liquid crystal (11) is maintained in the smectic A phase state during steady state.

Furthermore, (50) indicates a projection means, by which the image on the liquid crystal cell (10) is enlarged and projected onto the screen (60). That is, projection light is taken out from a light source, for example, a 150W halogen lamp (51), and this projection light is transmitted to
) is irradiated onto the liquid crystal cell (lO) through the optical path of the cell (
10) passes through the prism (26) and is irradiated onto the screen (60) by the projection lens (57).

Therefore, the image written in the cell (10) is enlarged and displayed on the screen (58).

In this example, this screen (58) is a display screen in the projection means (50) and is also integrated with the tablet board (61) of the tablet (60). It is configured as shown in Figure 4. That is, in the same figure, (59)
is a flat and transparent glass plate, and the surface on the projection light side is a frosted glass surface (59A) and is used as a display screen (59A).
8) and this ground glass surface (59A
), a plurality of transparent, striped electrodes (63) are arranged horizontally and separated from each other. Further, (64) is a flat and transparent glass plate, and on the opposite surface to the glass plate (59), transparent and striped bi-soft electrodes (65) are separated from each other in the vertical direction. are arranged. And these glass plates (
59) and (64) are closely connected with an insulating layer (not shown) in between to form a transparent tablet board (61). The thicknesses of the glass plates (59) and (64) are, for example, 1 fl and 3° C.m, respectively, and the sizes, that is, the sizes of the screen (58) and the tablet board (61), are, for example, A4 size. .

Further, (66) is a tablet pen, in which the electrode (pen tip) is insulated from the grip, and the tablet board (61
) When a voltage (scan pulse) is supplied to the electrodes (63) and (65), the electric field is caught.

In addition, (70) indicates a microcomputer that performs various controls, and (
71) is its CPU, (72) is a ROM in which a control program is written, (73) is a RAM for a work area, (74) is an input port, and (75).

(76) is an output boat, and these circuits (72) to (76
) is connected to the CPU (71) through a system bus (79). Furthermore, the CPU (71) has a bus (79
) is connected to a full keyboard (77) and a floppy disk device (78).

Then, when the keyboard (77) is operated to enter the write mode, ER=O is set and the microcomputer (70) is set to write mode.
), a tablet version of the scan pulse is formed,
This pulse passes through the boat (75) to the electrode (14),
(15) and scanning is performed. At this time, the tablet pen (66) is attached to the glass plate (
64), the scan pulse will be applied to the tablet pen (
66), and this is taken into the microcomputer (70) through the boat (74).

Then, in the microcontroller (70), the tablet pen (
The skin pulse detected by the electrode (14)
), (15) is determined, and from this determination result, the coordinates indicated by the tablet pen (66) are determined, and according to these coordinates, the address signals Ax, Ay is formed,
These signals Ax and Ay are sent to the D/A converter (31) through the boat (76).

(32) and the display data is
(76) is supplied to the multivibrator (21). Therefore, the corresponding pixel (coordinates) of the liquid crystal cell (10) is irradiated with laser light, and this pixel is rendered opaque.
Since this is projected onto the screen (58) by projector 1 (50), the pen (66)
) A black dot will be displayed at the location you hit.

In this way, when drawing is performed on the tablet left board (61) with the tablet pen (66), a dot is written in the corresponding part of the cell (10) and the trajectory of the pen (66) is displayed on the screen (58). go.

Further, when the keyboard (77) is operated to enter the erase mode, the erase voltage ER is supplied to the cell (10), and the entire surface or the portion designated by the pen (66) is erased.

Furthermore, when the execution of a program is specified from the keyboard (77), the corresponding program is loaded from the floppy disk device (78) to the RAM (73) and executed, and the graph of the execution result etc. is written to the liquid crystal cell 0ω. is displayed on the screen (58).

Thus, according to this display device, the tablet (60)
Various images can be written on the liquid crystal cell member and displayed on the screen (58) using software. Furthermore, the image written in the liquid crystal cell OI can be erased or rewritten, that is, can be edited.

Furthermore, while making the tablet board (61) transparent,
Since it is closely integrated with the display screen (58), the drawing position and the display position match, and therefore, the operability is excellent.

In addition, a tablet board (61) and a display screen (5
Since it is a flat plate and thin with a thickness of 1 to 2 nm, there is almost no parallax between the drawing position of the tablet pen and the displayed trajectory. Furthermore, since the image written on the liquid crystal cell (10) is projected onto the screen (58) for display, the distortion of the displayed image is much smaller than that of an image displayed on a CRT.
Moreover, it is not affected by contrast, brightness, or geomagnetism, and therefore does not cause parallax.

Furthermore, since the image of the liquid crystal cell (10) is projected onto the screen (58) using the light of the lamp (51) for display, flicker does not occur and there is almost no strain on the eyes of the operator. Furthermore, since it is possible to display on an A4 size screen (58) with a resolution of 2000 dots x 2000 dots, it is possible to perform high resolution and high quality display.

(Reference: Specification and drawings of Japanese Patent Application No. 59-278509) [Problems to be solved by the invention] However, in the above-mentioned device, it is not possible to write an image on the liquid crystal cell Ql and display it on the screen (58). However, the image written in the cell 0ω cannot be read as data. Therefore, even if a sufficiently satisfactory image is displayed through repeated editing, it cannot be saved as new data.

Furthermore, if the liquid crystal cell 0 on which an image is written is regarded as an image source, it is a transmission type image source, but if an image is drawn on paper, it is a reflection type image source.

This invention makes it possible to read images drawn on various media, including liquid crystal cells, as data, not only when the media are transmissive, but also when the media are reflective. That is.

[Means for solving problems]

The present invention automatically determines whether an image source is a transparent type or a reflective type, and extracts an image data signal according to the determination result.

[Effect]

Appropriate image data signals are extracted whether the image source is of the transmission or reflection type.

〔Example〕

In Figure 1, (1) indicates an image source, which is
These include a transmissive type such as the above-mentioned liquid crystal cell OI and transparent film, a reflective type such as paper, or an intermediate between the two types.

Further, a writing means (20) and a scanning means (30
) is also used to scan the image source (11) with a readout laser beam.For this reason, a signal for controlling the output of the laser beam from the microcomputer (70) is sent to the laser diode (23) via the drive circuit (22). )
The laser beam is supplied to a continuous and constant intensity, and in consideration of the case where the source (1) is a liquid crystal cell αl, the input is such that writing is not possible, for example 5.
mW (30 mW during writing). Furthermore, a half mirror (28) is provided in place of the prism (26), and laser light is supplied to the source (1). Also,
Vertical and horizontal synchronizing pulses are formed in the forming circuit (37), and these synchronizing pulses are supplied to the microcomputer (70), and depending on the change in the address signal A The standard is to perform rusk scanning.

Therefore, the image source (1) will be scanned by a weak, unchanging laser beam, that is, a readout laser beam, and the image source (1) will be scanned by the laser beam transmitted through this source (1). Alternatively, the laser beam reflected by the source (1) is obtained, and the intensity of the transmitted or reflected laser beam is modulated in accordance with the density of the pixel at the scanning position of the source (1).

Therefore, as a reader It (80), a condenser lens (81) and a light receiving element such as a photodiode (82) are provided at a position opposite to the mirror (28) of the image source (1). 1) is supplied to a diode (82) and converted into an image data signal St, and this signal St is sent to an amplifier (83).
The signal is supplied to the switch circuit (86) through the switch circuit (86).

Further, as a reading means (80), an image source (1
), a light receiving element, for example, a photomultiplier (84) is provided with a mirror (28) in between, and the laser beam reflected by the image source (1) is supplied to the multiplier (84) through the mirror (28). is converted into an image data signal Sr, and this signal Sr is supplied to a switch circuit (86) through an amplifier (85).

In this case, the signals St and Sr essentially have the same information, but their level or S/N depends on the transmittance and reflectance of the image source (1) for the laser beam.
etc. are different.

Therefore, the signal S from the amplifiers (83) and (85)
t.

Sr is supplied to level detection circuits (91) and (92), and signals indicating the peak-to-peak levels of signals St and Sr are extracted, and these signals are supplied to a comparison circuit (93), and The comparison output is supplied to the switch circuit (86) as a control signal, and the signal St
, Sr with a higher level is taken out from the switch circuit (86).

Then, this extracted signal St or signal Sr is supplied to the interface (87), and a synchronization pulse is sent from the forming circuit (37) to the interface (87).
) and added to the signal St or signal Sr,
The signal St or Sr having this synchronization pulse is connected to the terminal (
88).

Thus, according to the present invention, the image of the image source (1) can be extracted as an image data signal. Moreover, in that case, no matter what the transmittance and reflectance of the image source (1) for laser light are, that is, whether the image source (1) is a transmissive type or a reflective type, the level It is possible to obtain a signal with a thick signal and a good S/N ratio.

In the above description, the signal St or Sr from the switch circuit (86) may be digitized and stored in a display memory or saved on a floppy disk.

〔Effect of the invention〕

According to this invention, the image of the image source (1) can be extracted as an image data signal. Moreover, in that case, no matter what the transmittance and reflectance of the image source (1) for laser light are, that is, whether the image source (11) is a transmissive type or a reflective type, the level is A thick signal with good S/N can be obtained.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an example of the present invention, and FIGS. 2 to 4 are diagrams for explaining the same. (10) is a liquid crystal cell, (20) is a writing means, (30
) is a scanning means, (50) is a projection means, (60) is a tablet left, (70) is a microcomputer, and (80) is a reading means.

Claims (1)

[Scope of Claims] An image source on which an image is written; means for scanning this image source with laser light; and means for scanning the image source with laser light, which transmits the laser light transmitted through the image source a first light receiving element that receives light; a second light receiving element that receives laser light reflected from the image source when the image source is scanned by the laser light; and a second light receiving element that receives the laser light reflected from the image source; first and second level detection circuits that respectively detect the level of the output signal; a comparison circuit that compares the detection outputs of these first and second level detection circuits; An image reading device comprising: a switch circuit that takes out one of the output signals of the first and second light receiving elements as image data of the image source.