JPS59162523A - Liquid crystal shutter array - Google Patents

Abstract

PURPOSE:To improve the resolving power and sharpness of an image by specifying the ratio of the interval between shutter opening parts and the parallel- directional length of the shutter opening parts of the shutter array of a 1/2 time- division driving system. CONSTITUTION:A shutter is constituted by arraying plural shutter opening parts 11 (11a, 11b...) zigzag at intersections of row electrodes 12a and 12b, and signal electrodes 13 (13a-13d.). A metallic light-shield mask is formed on the row electrodes 12a and 12b in areas except at the opening parts 11. The interval D between shutter opening parts in the 1st and the 2nd row is 1.22-2.0 times as large and the parallel-directional length of the shutter opening part. Consequently, bleeding of a dot image is prevented effectively and the resolving power and sharpness of an image are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal shutter array, and more particularly to an improvement in dot-shaped electrophotographic images formed by an electrophotographic printer having a liquid crystal shutter array optical signal generating section.

This liquid crystal shutter array utilizes the electro-optical modulation function of liquid crystal, and by arranging the modulation sections in an array, shining light on them and selectively outputting the transmitted light, it converts into electrical image signals. A digital copy can be obtained by forming a corresponding optical signal and irradiating the electrophotographic photoreceptor with this optical signal.

The advantages of this liquid crystal-optical shutter array are: 1. When used in an electrophotographic printer, the printer device can be made smaller; 2. It is easier to use for polygon scanners used in LBPs (laser beam printers). Because there are no mechanically driven parts, there is no noise, and the requirements for strict mechanical precision are small.

However, electrophotographic images formed using an electrophotographic printer having this liquid crystal shutter array optical signal generating section have a disadvantage in that they are inferior in resolution compared to electrophotographic images formed using a laser beam printer. There is. In particular, in a liquid crystal shutter array using the %% time-division driving method, a plurality of shutter openings are arranged in two rows in a staggered manner, and the shutter openings in the first row are operated in a % period, and the shutter openings in the first row are operated in the next % period. The shutter openings in the second row are operated to form an l-line image, but the dot-like image formed by the operation of the shirtter openings in the first row and the next dot are formed on the l-line image. Since the dot-like images formed by the operation of the shutter openings in the second line overlapped, a difference in density between the images of 11 lines occurred. Moreover, even when 11 dot-shaped images were observed, one "bleed" was observed at the periphery of the dot-shaped images, indicating that the dot-shaped images were not sharp.

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal shutter array that eliminates the above-mentioned drawbacks.

Another object of the present invention is to provide a liquid crystal shutter array that improves the resolution and sharpness of electrophotographic images formed by an electrophotographic printer using a liquid crystal shutter array optical signal generator. The liquid crystal shutter array of the present invention has two
The distance between the plurality of shirt flap openings arranged in parallel in the first row and the second row in the plurality of shirt flap openings arranged in parallel in a row is 1 of the length of the shirt flap openings in the parallel direction.
．． It is characterized by having a length of 22 times to 2.0 times. It is possible to improve the resolution and sharpness of multi-dot-shaped images formed by an electrophotographic printer using this liquid crystal shutter array optical signal generating section, and therefore, no density unevenness is observed in a single line electrophotographic image. Sharp images can be formed. In particular, the distance between the plurality of shirt flap openings arranged in parallel is 1.4 to 1.8 times the length of the shirt flap openings in the parallel direction, particularly preferably 1.8 to 1.8 times the length of the shirt flap openings in the parallel direction.
If you set the length to 5 times to 1.6 times, the dot-like image
It can effectively prevent "bleeding" and improve image resolution and sharpness.

The present invention will be explained below with reference to the drawings.

The shutter shown in FIGS. 1, 2, and 3 has a plurality of shutter openings 11 (lla, llb, etc.) arranged in a zigzag pattern, and row electrodes 12a and 12b. Signal electrodes 13 (13a, 13b, 13c
.

13d,...) is located at the intersection. The row electrode substrate used for this shutter has row electrodes 12a and 12b on the substrate 14 (glass, plastic, etc.) in the area excluding the area 11'(ll'a,ll'b) where the shutter opening 11 is formed. A metal light shielding mask 15 is formed thereon. Furthermore, a colored insulating film 16 is arranged between the row electrodes 12a and 12b. Further, in the figure, numeral 17 indicates an insulating film made of resin or the like.0 An example of the process of forming the row electrode substrate shown in FIG. 2 will be explained.

In FIG. 2, electrode row electrodes 123' and 12b made of a transparent conductive thin film and a metal light-shielding mask 15 are formed on the inner surface of the glass substrate 14, and polyvinyl alcohol (polyvinyl alcohol) is used as an alignment film on the inner surface of the glass substrate 14. PVA) film is formed. PVA is Go7/-ru (Nippon Gosei Kagaku Kogyo) BG-
Using a 10% aqueous solution of 05 and adding ammonium dichromate as a photosensitive skeleton agent at a ratio of 5% to the solid content of the above ffA, it was spin-coated (6000 rpm,
10") and then heated at 60°C for 15 minutes to form an insulating film 17. Next, with the peripheral edge covered with a mask, a PVA film (insulating film 1
7) was exposed for 10-15 seconds and developed with pure water for 30 seconds to remove the unexposed areas. After blow-drying with N2 gas,
After heating and drying at ℃ for 5 minutes, the surface of the PVA membrane is subjected to alignment treatment by rubbing.

Next, a photoresist layer (FPPR4800) was spin coated (2000 rpm, 10”) and heated at 80°C for 5 minutes to form a photoresist layer.
7. Apply a layer of photoresist with a mask covering the area.
After exposure for a second, development was performed with a developer to remove the photoresist layer in 16 areas in the figure.

Next, the PVA film is dyed by immersing it in a dye solution for 5 minutes to form a colored insulating film 16. The dye is 8umi fix
Black ENB (Sumain Chemical), 5olophe
nyINGL (+Pageigy), C1bacet G
Rey NH (Ciba Geigy) may be used by dissolving it in a 2% aqueous solution of NH and OH, and the desired concentration may be obtained by sequentially immersing it in two or three types of dyes. Next, after rinsing with pure water, rinse with methyl ethyl ketone.
Remove remaining photoresist layer, rinse with isopropyl alcohol, dry with Fron paper, bake (1)
801:, 15'), etc. to form the row electrode 12a.
A light-shielding mask in which the gap between and 12b is opaquely dyed is completed.

Further, an example of the process of forming the row electrode substrate shown in FIG. 3 will be explained. In FIG. 3, it is assumed that row electrodes 12a and 12b made of transparent conductive thin films and a remaining end light shielding mask 15 are formed on the inner surface of a glass substrate 14, and a polyvinyl alcohol (PVA) film is formed thereon. ffA is a 10% aqueous solution of Gohsenol (Nippon Gosei Kagaku Kogyo) EG-05, and ammonium dichromate is added as a photosensitive sealant at a ratio of 5% to the solid content of the PVA.
, spin coating (6000 rpm, 10
'') and then heated at 60°C for 15 minutes.

Next, with the mask aligned so that light hits only the gap between the metal light-shielding mask 15, a PVA film 10-1 is applied.
The film was exposed for 5 seconds and developed with pure water for 930 seconds to remove the unexposed areas. Next, it is blown dry with N2 gas and then heated and dried at 80° C. for 5 minutes.

The PVA film is then dyed by immersion in the dye for 5 minutes. The dye used was one of Sumifix Black BNS (Sumima Kagaku), 5olopheny INGL (Ciba Geigy), and C1bacetGrey NH (Ciba Geigy) dissolved in a 2% aqueous solution of NH4OH (7).
The desired concentration may be obtained by immersion in two or three dyes sequentially. As a result, the fi PVA film is dyed, and a colored insulating film 16 is formed.

Next, after rinsing with pure water, rinse with isopropyl alcohol, dry with Fron paper, and bake (180℃).
, 15'), etc., to complete a light-shielding mask in which the gap portions are opaquely dyed.

Then, polyimide resin (5P-5 manufactured by Toton) was applied to the surface.
10) was spin-coated using a 2.5% NMP solution (3).
000 rpm for 60 seconds), the insulating film 17 is formed by heating at 300° C. for 30 minutes.

After removing the polyimide film on the seal and electrode terminal portions (etching for 10 minutes at 60° C. using a 0% Alka IJ I aqueous solution), the alignment direction of the liquid crystal molecules is determined by rubbing. After a reflective metal such as chromium, aluminum, or silver is formed by vapor deposition or plating, an IJ process can be employed. When the metal light-shielding mask 25 is made of chromium, it has a film thickness of about 300 to 2000 layers.

When a liquid crystal shutter array is constructed by combining a glass substrate on which a light-shielding mask is formed as described above and a glass substrate having a conventional through-hole counter electrode and arranging a polarizing plate, the voltage is not applied as described above. Most of the small amount of light that passes through the area is absorbed by the dye mask, preventing areas other than the data symbol from being exposed to light when writing data.

Of course, the same effect can be obtained even if the light-shielding mask is formed on the opposite electrode side, and in this case as well, the light-shielding mask that covers the part other than the part corresponding to the pattern electrode can be formed using the same method as described above. . Moreover, it is of course possible to form a light shielding screen on both the pattern electrode side and the counter electrode side. FIG. 4 is a plan view showing a part of the liquid crystal shutter array of the present invention.

In a specific example of the present invention, a liquid crystal shutter array having the electrode structure for time division driving shown in FIG. 1 can be used. In the array shown in FIG. 4, two row electrodes 12a and 12b are arranged on a first substrate, and a second
The substrate has signal electrodes 13 (13a, 13b, 13c, 1) that intersect with two rows of row electrodes 12a and 12b.
3d −・−= ) are arranged.

Shutter openings are formed at opposing portions of the row electrodes 12a and 12b and the signal electrode 13, respectively.

A, , A, ,...)"1 * A2
*I's... are indicated by diagonal lines. Among these shirt openings arranged in a staggered pattern, AI-A2-A-s--... which are arranged in parallel in the first row.
・The length in the parallel direction of AI', 4', A3', . . . arranged in parallel in the second row and the length D1' in the parallel direction of -A.

) and the length D2 between the shirt openings (A
, '-＾z, -A2'A3', ...... ), the relationship between the length D2' is Dt = (1,
22~2.0) X Dt,'= (1,22~
2. o) It is suitable to set 0 to 110 mm-140 ssm in a preferred concrete example having the relationship of
D, and D! ' can be set to 1201 m.

It is generally desirable that the length of the row electrodes 12a and 12b in the longitudinal direction be approximately 210 mm long so as to match the length in the lateral direction of Japanese Industrial Standard A-4 size. The number of shirt openings formed at this time is 1050 (5 dots/pus) in the first row, and 1050 (5 dots/pus) in the second row.
ffIIK), and the first row shirt openings and the second row shirt openings can be arranged in a staggered manner as shown in FIG.

In such a liquid crystal shutter array, polarizing plates are arranged on the outside of the first substrate and the second substrate, respectively, and arrows 21 and 22
It is in a crossed nicol state as shown by . The inner wall surfaces of the first and second substrates are subjected to a rubbing treatment or the like so that the P-type liquid crystal sandwiched between them is initially oriented in the direction of arrow 23 (approximately 45 degrees to the polarization direction of the polarizing plate). A special orientation treatment has been applied.

To simplify the following explanation, attention will be paid to the shutter openings A1 and A2 corresponding to the row electrode 12a and the shutter openings AI' and A2' corresponding to the row electrode 12b, and these shutter openings A1. A2. A,' and A2'
The operation will be explained using an example.

FIG. 5 shows a time chart used in the driving method of the present invention. Time T, , T,′, T,II...
.times. is the time during which the shutter openings corresponding to the row electrode 12a operate, and all the shirt shutter openings corresponding to the row electrode 12b stop operating. Time Tt *T
2'+T*'... is the time during which the shutter opening corresponding to the row electrode 12b operates;
The corresponding shirt opening on 2a is inactive. That is, time T, , T, Z III, I+...
..., the shutter openings AI' and A are controlled by the signals S1 and S given to the signal electrodes 13b and 13c.
2' should not be affected, and the time T, ,
T, Z T2//..., the signals SI and 82 must not affect the operation of the shutter openings A and A2.

The present invention has an important meaning in that it overcomes the above points.

First, time 'r, t Tl' s T+''...
- Explain the operation of each shirt opening in . Fifth
As shown in the time chart in the figure, voltages C and C' are applied to row electrodes 12a and 12b, respectively. At this time, voltage C is in opposite phase to voltage C'. On the contrary,
Signal electrodes 13b and 13c K address row electrode 1
2a It is possible to determine whether the shutter is on or off by keeping the voltage in phase with the applied voltage C or at a certain voltage level.

At time T shown in FIG. 5, the shirt opening A
An example is given in which only I is in a shutter-on state (a state in which irradiation light is transmitted). However, in this example, at the end of the time for addressing one row, there is always a time τ to which a signal prompting the OFF state is inserted.
This is provided.

To explain that the shutter openings A1' and A1' of the corresponding row of the row electrode 12b are in the shutter-off state (state of blocking irradiation light) at time T1, % A1' l
The operation of the liquid crystal at ' is determined by the voltage C' and the electric field caused by the signal s1. Since C' and S are voltage signals with opposite phases to each other, the liquid crystal layers at A and ' are in a state (off state) in which no light is transmitted even though they are subjected to a strong electric field. on the other hand,
' is determined by C' and 82, but since %82 is kept at a certain constant voltage level, h A!
A relatively strong electric field is also applied to the liquid crystal layer at ', which turns it off.

On the other hand, A2 is determined by signal S2 and voltage C, but S2
Since is at a constant signal level, a relatively strong electric field acts on the liquid crystal layer at A2 due to the voltage C, so that it is in an off state. However, in A8, it is determined by C and 81, but %8
Since 1 is a voltage signal that is in phase with C, a voltage that is the absolute value of Ic-5,+ is not applied to the liquid crystal layer in AI, and this results in a zero or relatively weak electric field, so light Creates a transparent state (on state).

Similarly, the time T for addressing the row formed by the row electrode 12a
In I′, both 戊 and A are in the on state,
A1' and 戊' are in a geo-off state due to relatively strong electric fields determined by Sl, S2 and C', respectively.

In summary, at the time when a row of row electrodes 12a is addressed, the shutter openings of rows of row electrodes 12b are always reliably in the OFF state, regardless of the states of signals S1 and 82.

Next, the time 'r for addressing the row formed by the row electrode 12b,
I T2Z T2'... will be explained.

At time T2, only A,' is on, and at time T,', only A2' is on. 'r, I
Voltage C' at rr2/ v T2''...
is in reverse phase with respect to C. On the other hand, whether the signal voltages S and 82 are in phase with C' or maintained at a certain voltage level determines whether the shutter is turned on or off. In the liquid crystal layer at the shutter openings A and A2, the A at the previous time T1゜T, Z T:/...
As explained above, a relatively strong electric field always acts on I' and A,', so that the off state is maintained. In contrast, time'
r,? 'r,', T2''...A in K
I'ton' is the previous T1 depending on the signal S, and S.
．． T□', T: As explained for A1 and A2 in /, you can choose between on and off states.0 where 'r, *'
r, I TI's Tfi's Ti'* T2'...
The τ provided at the end of each time period is to uniformly turn off all the shutter openings, and this causes the signals S and 82 to be at a constant voltage level. It was well done. By inputting this erase signal, it is possible to reliably block light transmission from the shutter opening which should then be in the OFF state.

Further, the printer shown in FIG. 6 shows a schematic configuration of a printer that uses a liquid crystal shutter array to apply an optical signal to a photoreceptor.

However, the charger etc. are omitted. 61 is a liquid crystal shutter array, 62 is a photosensitive drum, 63 is a light source (fluorescent lamp, etc.),
64 is a SELFOC lens array, and 65 is a condensing cover. As mentioned above, when a liquid crystal shutter array is used, the printer can be assembled in a more compact form than the conventional LBP.

Such an electrophotographic printer, i.e. 70am~9Q
A printer comprising a liquid crystal shutter array optical signal generating section having a length in the parallel direction of shutter openings of 10 m and arranged in a staggered manner with an interval of 1101!1 m to 130 μm 1% m between the shutter openings. In the case of 1 nonta, it is possible to form a dot-like image with a size of about io onm, and therefore it is possible to improve the sharpness of the dot-like image; to form a good reproduced image without density unevenness 7
I can do 5.

[Brief explanation of drawings]

FIG. 1 is a plan view of the liquid crystal shutter array of the present invention;
2 and 3 are sectional views taken along line A-A of the row electrode substrate. FIG. 4 is a plan view of the row electrodes and signal electrodes of the present invention. FIG. 5 is an explanatory diagram showing a time chart when the liquid crystal shutter array of the present invention is operated. Figure 6 shows
0 11 (lla, llb, . . . ) is a schematic perspective view of an electrophotographic printer using the liquid crystal shutter array of the present invention.
- Shirt openings, 12 (12a, 12b,...
)... Row electrode (common electrode), 13 (
13a, 13b,...-)... Signal electrode, 14-... Substrate, 15... Metal light-shielding mask,
16... Colored insulating film, 17... Insulating film, 21.22
...Polarization direction, 23...Rubbing direction, 61...
Liquid crystal shutter array, 62... Photosensitive drum, 63...
- Light source, 64...Selfoc lens, 65...Condensing cut-out, D,, D1'...Length in the parallel direction of the shutter opening, D2 * D2'...・
- Distance between multiple shirt openings arranged in parallel direction. Heart 3M

Claims (1)

[Claims] A plurality of signal electrodes and two electrodes arranged opposite to the signal electrodes.
In a liquid crystal shutter array in which the row electrodes of a book are arranged in an IJ box-like electrode structure and the opposing portions of the signal electrode and the row electrode are shutter openings, the distance between the plurality of shutter openings arranged in parallel direction is A liquid crystal shutter array having a length of 1.22 to 2.0 times the length of the shutter openings in the parallel direction.