JPS6244894A - Reader - Google Patents

Abstract

PURPOSE:To increase the freedom of the number of reading picture elements or the like and to reduce the cost of a device by arranging a transmission type liquid crystal plate consisting of plural dots on the optical path of an optical system and successively turning on and off the respective dots. CONSTITUTION:A light source 23 is arranged on the uppermost part of a body tube 22 and an optical system 24 for collimating light radiated from the light source 23 is arranged under the light source 23. In addition, a color/temperature converting filter 25 and the transmission type liquid crystal plate 26 consisting of plural dots are successively arranged under the optical system 24. Respective dots of the plate 26 are successively turned ON and OFF and the surface 28 of an original is irradiated by the light transmitted through the dots. The reflected light from the original surface 28 is detected by a photosensor 29 arranged in the body tube 22.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention 1] The present invention relates to a reading device that optically reads information such as characters and graphics hidden on a paper surface.

[Prior Art and its Problems] Conventionally, a reading device that optically reads information such as characters and figures written on paper or the like is generally configured as shown in FIG. 6 or 7. That is, the reading device 1 shown in FIG. 6 is equipped with an optical system 3, a color temperature conversion filter 4, and an image sensor 5 such as a COD in a lens barrel 2, and has an illumination device outside the lens barrel 2 that illuminates the document surface. It is equipped with a light source 1 for The reading device 1 configured as described above illuminates the document surface 〇 to be read with the light source 7, and uses the optical system 3 to form an image of the reflected light from the document surface 6 on the image sensor 5. ing.

Therefore, in the reading device 1 shown in FIG. 6, the number of pixels for reading is completely controlled by the image sensor 5.

In the line type, the image sensor 5 has 32 to 2
It is commercially available in 2n pitch up to about 0.048 pixels, and most of them are available, but in area type, 1.2 pixels are available in addition to those for video cameras.
There are only a few different types, and the color area is only available for video cameras, so it is difficult and inconvenient to use, with no flexibility at all, and is extremely expensive. In addition, the image sensor 5
Since a large number of photodiodes are arranged on one chip, the light-receiving surface of the photodiode becomes small, resulting in a small output signal and making it difficult to design a light-receiving circuit.

Further, the reading device 1 shown in FIG. 7 has a plurality of L E O 11 arranged as light sources at the upper end of the lens barrel 2, and furthermore, an optical system 3 is arranged approximately in the center of the lens barrel 2, and One phototransistor 12 is arranged on each of the four sides of the lower part. At the time of reading, the lens barrel 2 is placed on the document surface 0, the 1EDs 11 are sequentially emitted, and the light is formed into a light spot by the optical system 3 and an image is formed on the document surface 6. Then, the reflected light from the document surface 6 is detected by the phototransistor 12.

In the method shown in Fig. 7 above, if the integration rate of LED11 is poor, it is not possible to increase the number of pixels, and it is not only impossible to use it as an area sensor, but also because the light of LEI11 has a narrow wavelength width, Unable to read. Also, L E D
The amount of light from photo 11 is also small, and therefore the output signal of photo 1 transistor 12 is small, making the subsequent processing circuit complex.

[Object of the Invention] The present invention has been made in view of the above points, and an object of the present invention is to provide a reading device that has a high degree of freedom in terms of the number of pixels to be read, etc., and can be configured at low cost.

[Summary of the Invention] The present invention provides an optical system that converts light from the light source into parallel light or diffused light, and a transmissive liquid crystal plate having a multi-drive configuration, which are sequentially disposed facing each other between a light source and a document surface, and the above-mentioned liquid crystal By controlling the plate, light is transmitted dot by dot to sequentially illuminate only one point on the document surface, and the reflected light is detected.

[First Embodiment of the Invention] The present invention will be described in detail below with reference to the drawings. first,
The configuration of the reading device 21 will be explained with reference to FIG.

In FIG. 1, reference numeral 22 denotes a lens barrel, at the top of which a light source 23 such as a halogen lamp or an incandescent lamp is provided, and below it is an optical system 2 for converting the light from the light source 23 into parallel rays.
4 are arranged. Further, below the optical system 24, a color temperature conversion filter 25 for converting the light from the optical system 24 into white and an nxn dot transmission type liquid crystal plate 26 are arranged in order at a predetermined interval. In this case, a mask 27 is provided on the upper side of the liquid crystal plate 26 in its periphery to remove unnecessary light. The light taken out through the liquid crystal plate 26 is irradiated onto the document surface 28-F, and one photosensor 29 is arranged on each of the lower sides of the lens barrel 22 to receive the reflected light. Ru. For the photosensor 29, a phototransistor, a photodiode, etc. is used in the case of monochrome processing, and a color sensor is used in the case of color processing. As this color sensor, for example, one element of 5
Either prepare 3 photodiodes or phototransistors such as iPIN or GaASP and attach R, G, and B filters to the front, or use 3-element photodiodes or phototransistors each corresponding to R1GXB on the front. A device with a filter attached and housed in one package is used. The output signal of the photosensor 29 is then sent to a black and white signal processing circuit shown in FIG. 2 or a color signal processing circuit shown in FIG. 3.

Next, the configuration of the monochrome signal processing circuit shown in FIG. 2 will be explained. In FIG. 2, reference numeral 31 denotes a timing control section, which starts its operation in response to a start pulse a sent from the host side CPU (not shown) via the interface section 32, and is controlled by the timing control section 1- in FIG. As shown, a lamp-on signal b1, a liquid crystal dot switching signal C1, a latch timing signal d1, a synchronization signal e for data acquisition, a low signal q, etc. are output. The lamp-on signal C output from the timing control section 31 is sent to the light source driver 33, and the liquid crystal dot switching signal C is sent to the liquid crystal control section 34. The light source driver 33 includes a timing control section 3
The F light distribution source 23 is turned on in accordance with the lamp-on signal from 1. Further, the liquid crystal control section 34 is activated by a start pulse a given through the interface section 32, and outputs a control signal to the segment driver 35 and the common driver 36 in accordance with the liquid crystal dot switching signal C from the timing control section 31. The segment driver 35 and common driver 36 operate according to control signals from the liquid crystal control section 34 and drive the liquid crystal plate 26. When the segment driver 35 and the common driver 36 finish scanning all the dots on the liquid crystal plate 26, the scan end signal f to the timing control section 31 is outputted from the liquid crystal fan 1 to the roll section 34.

On the other hand, the signals output from the four 7-point sensors 29 are:
After being amplified by amplifiers 37a to 37d, the signals are input to comparator 39 via summing amplifier 38.

This comparator 39 converts the signal from the summing amplifier 38 into binary data of "1" and "0", latches it in synchronization with the latch timing signal lad from the timing control section 31, and connects the interface section 32. It is output to the host side CP tJ via the host side CP tJ.

Further, the interface unit 32 sends the data acquisition synchronization signal e and the signal @0 outputted from the timing control unit 31 to the host side CPU.

Next, a signal processing circuit when a color sensor is used as the sensor 29 will be explained with reference to FIG. The timing control section 31, interface section 32, light source driver 33, liquid crystal control section 34, segment driver 35, and common driver 36 have the same configuration as the black and white signal processing circuit shown in FIG. 2, so a detailed explanation thereof will be omitted. do. Therefore, R and G are respectively output from the four photosensors 29.

The B color signal is transmitted through amplifiers 37a 1 to 37a 3.3.
7b1 to 37b3. After being amplified by 37cl to 37G3, a summing amplifier 38 is applied to each R, G, and B color signal.
The signals are input to comparators 39a to 39G via a to 38c. The comparators 39a to 39c convert the signals from the summing amplifiers 388 to 38C into binary data of "1" and "0", and also latch them in synchronization with the latch timing signal d from the timing 4 control section 31. , and output to the host side CPU via the interface section 32.

Further, the interface section 32 sends out the data acquisition synchronization signal e and the busy signal 0 outputted from the timing control section 31 to the CPUs on the host 1 side.

Next, the operation when using the monochrome photo sensor +j-29 will be explained with reference to FIGS. 1, 2, and 4. When reading, after placing the reading device 21 shown in FIG. 1 on the portion of the document surface 28 that is desired to be read, a key operation is performed to instruct the reader to start reading. With this key operation, the host side
A start pulse a for instructing the start of reading is given from the PU via the interface section 32, and is input to the timing control section 31 and the liquid crystal control section 34. When the start pulse a is input, the timing control section 31 detects the fall of the start pulse a as shown in FIG.
At the same time, a lamp-on signal is output to the light source driver 33 to turn on the light source 23. Then, the light emitted from the light source 23 is converted into parallel light by the optical system 24, and further converted into white light by the color temperature conversion filter 25, which enters the liquid crystal plate 26.

On the other hand, the liquid crystal control section 34 is reset by the start pulse a, and keeps all the dots on the liquid crystal plate 26 in an off state. Therefore, the light incident on the liquid crystal plate 26 is not sent to the document surface 28. After waiting for a certain period of time until the luminous intensity of the light source 23 becomes stable, the timing control section 31 outputs the liquid crystal dot switching signal C to the liquid crystal control section 34. When the liquid crystal dot switching signal C is sent from the timing control unit 31, the liquid crystal control unit 34 controls the segment driver 35 in synchronization with the rising edge of the liquid crystal dot switching signal C.
, sends a signal to the common driver 36, and first sends a signal to the liquid crystal panel 26.
Turn only the first dot on (transparent state). LCD board 2
When the first dot 6 is turned on, only the light from the first dot out of the light incident on the liquid crystal plate 26 is transmitted to the original surface 2.
8 and the reflected light enters the 7 otosensor 29. Therefore, a signal corresponding to the incident light is output from the photosensor 29 and sent to the amplifiers 37a to 37d. The output signals of the amplifiers 37 a to 37 d are summed and amplified by a summing amplifier 38 and input to a comparator 39 . On the other hand, after outputting the liquid crystal dot switching signal C, the timing l1l part 31 outputs a latch timing signal d to the comparator 39 until the liquid crystal and photocurrent are stabilized. This comparator 39 converts the signal from the summing amplifier 38 into binary data of "1" or "0" in synchronization with the latch timing signal d, latches it, and sends the signal to the host side CPU via the interface section 32. Output to. Subsequently, the timing control section 31 outputs the data acquisition synchronization signal e to the CPU on the host 1 side through the interface section 32. This boss 1 ~ side CP
U takes in data from the comparator 39 and the like at the falling edge of the data taking synchronization signal e.

Thereafter, the timing control section 31 outputs the next liquid crystal driver]/switching signal C to the liquid crystal control section 34.

The liquid crystal control section 34 receives the liquid crystal dot switching signal C.
At the rising edge of the dot, the segment driver 35 and the common driver 36 turn off the dot that was currently on, that is, the first dot, and at the same time turn on the next dot, the second dot.
Outputs a signal to. Thereafter, by performing the same operation for the first to nllth dots 1-, all dots can be read. And the above nn1001
The first liquid crystal dot switching signal C is the timing control surface part 31.
When the signal is sent to the liquid crystal control section 34, the liquid crystal control section 34 turns off all dots at the rising edge of the liquid crystal dot switching signal C and outputs a scan end signal f to the timing control section 31. The timing control section 31 then outputs the latch timing signal d once again to output the data ``O''.
” (all black). Thereafter, the liquid crystal control unit 34 outputs an end-of-scan signal f to the timing control unit 31. The timing control unit 31 outputs an end-of-scan signal f from the liquid crystal control unit 34. is sent, the busy signal q is set to low level and waits for a certain period of time until the start pulse a arrives.The timing control section 31 controls the timing control section 31 when the start pulse a is sent within a certain period of time. The unit 31 sets the busy signal q to a high level, keeps the lamp on signal at a high level, repeats the above operation, performs the next reading, and if the start pulse a does not arrive within a certain period of time, lowers the lamp on signal. level and turns off the light source 23. This completes all processing.

Furthermore, in the processing circuit shown in FIG. 3 using a color sensor as the photosensor 29, the same operation as in FIG. 2 is performed on the R, G, and B color signals output from the photosensor 29. The detailed explanation will be omitted.

[Second Embodiment of the Invention] Next, a second embodiment of the invention will be described with reference to FIG. The reading device 21' in the second embodiment includes a color temperature conversion filter 25 and a transmission diffuser plate 3 below the light source 23.
0. The liquid crystal plates 26 are sequentially arranged at predetermined intervals, and the optical system 24 is further arranged below them at a predetermined interval, and the light from the light source 23 is diffused by the transmission type diffuser plate 30. After adjusting the overall brightness to a constant level, the liquid crystal plate 26 and the optical system 24
Accordingly, a bright spot as an image point is created on the document surface 28. In addition, in FIG. 5, the photosensor 2
9 is attached to the same location as in FIG. In the reading device 21 shown in FIG. 5 as well, the output signal of the photosensor 29 is processed by the circuit shown in FIG. 2 or 3, and the original surface 28 is read.

In the above embodiment, in order to increase the detection output, the lens barrel 2 is
Although a plurality of photosensors 29, for example four photosensors 29, are arranged in the document 2, it is possible to read the document surface 28 even if 11IIIiI photosensors 29 are provided instead of a plurality of photosensors 29. Also,
In the above embodiment, the liquid crystal panel 26 has an nxn dot matrix structure, but it may also have a line structure.

Further, in the above embodiment, the output signal of the summing amplifier 38 is converted into a binary signal by the comparator 39 to read characters, figures, etc.
If the /Dl inverter is used, a signal with multiple gradations can be obtained depending on the read signal, so it is possible to read not only characters and figures but also image information such as photographs.

[Effects of the Invention] As described in detail above, according to the present invention, an optical system for condensing or diffusing light and a transmissive liquid crystal plate having a dot matrix structure are arranged facing each other in sequence between the light source and the document surface, and the above-mentioned By controlling the liquid crystal panel, light passes through one dot at a time, sequentially illuminating only one point on the document surface, and the reflected light is detected, so there is a high degree of freedom in terms of the number of pixels to be read and their arrangement. 1. Post-processing is simple, colorization is particularly easy, and it can be constructed at low cost.

[Brief explanation of the drawing]

1 to 5 show embodiments of the present invention. FIG. 1 is a sectional view of the reading section in the first embodiment, FIG. 2 is a block diagram showing a black and white signal reading processing circuit, and FIG. 3 is a block diagram showing a color signal reading processing circuit, FIG. 4 is a timing chart for explaining the operation of the circuit shown in FIG. 2, and FIG. 5 is a reading diagram in the second embodiment of the present invention. 6 and 7 are cross-sectional views showing the structure of a conventional reading device. 21... Reading device, 22... Lens barrel, 23... Light source, 24... Optical system, 25... Color temperature conversion filter, 26... Liquid crystal plate, 27... Mask, 28 ... Original surface, 29 ... Photo sensor, 30 ... Transmissive diffuser plate, 31 ... Timing control section, 32 ... Interface section, 33 ... Light source driver, 34 ... Liquid crystal control Part, 35... Segment driver, 36
...Common driver, 37a to 37d...Amplifier,
38.38a-38c...Summing amplifier, 39.398
~39c...Comparator. Applicant's agent Patent attorney Takehiko Suzue Figure 1, Figure 21'' Factor 5, Figure 6

Claims (1)

[Claims] A light source for illumination, an optical system that converts the irradiated light from this light source into parallel light or diffused light, a transmissive liquid crystal plate consisting of a plurality of dots provided on the optical path of this optical system, and each dot of this liquid crystal plate. What is claimed is: 1. A reading device comprising: means for sequentially on/off controlling and sequentially scanning light over a document surface; and a photosensor for detecting reflected light from the document surface.