JPS6040610B2 - lcd light bulb - Google Patents

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to the structure of a liquid crystal light valve.

[Prior Art] Figures 1 and 2 show a variety of liquid crystal light valves and printing devices using the same.

The light source 1 is always on and always illuminates the liquid crystal light valve 2.

The liquid crystal light valve 2 has a plurality of minute shutters 8, which are optically opened and closed independently by a liquid crystal drive circuit, and allow or block the light from the light source 1 to pass therethrough. This part will be called an optical signal generating section 10. The optical signal obtained in this way reaches the photosensitive part 3, but since the photosensitive part 3 made of a photosensitive material has been charged in advance at the charging station 6, the part where the optical signal has reached is Then, the electrical charge disappears.

Therefore, a static latent image is formed in response to a write signal from the outside. The electrostatic latent image formed in this way is developed with colored toner in the developing section 4, transferred to a recording material such as paper, etc. in the transfer section 5, and fixed by heat etc. in the fixing section 7, completely. A fixed printed image is completed.

As mentioned above, this method does not require the precision high-speed optical scanning system of a laser printer, for example, so it can be expected to have various benefits, such as simpler structure and lower cost. However, there was a fatal problem with the idea of subordination, which made it surprising that it could be put into practical use.

The problem was that the writing speed was decidedly slow. The performance of the printing unit that can be applied to the various systems mentioned above requires a printing speed that outputs about 10 A4 sheets per minute, and a resolution of about 10 dots per desk/skin. In other words, this means that the printing speed is about 500 lines per second, that is, the time required to write one line is less than 2 seconds.

However, using a TN (twisted nematic) type liquid crystal and driving with a normal alternating voltage, as in the conventional idea, would make it impossible to achieve an open time of 2 seconds. As described below, although there is a growing demand for a high-speed, high-quality, low-cost, and compact printing device, the reality is that no satisfactory printing device has been realized.

The present invention fulfills these demands and provides a high-speed, high-quality printing device that is compact and inexpensive.
FIG. 3 is a diagram showing the frequency characteristics of dielectric anisotropy of a liquid crystal material. At frequencies lower than the crossover frequency 〆c, the dielectric anisotropy is positive and at higher frequencies it is negative. The electromagnetic anisotropy for Me and Meh is △GoL, △GoL>0 and △GoH<0, respectively. When a nematic liquid crystal with such characteristics is used as a TN type device, when a signal of ner is applied, the liquid crystal molecules are oriented in the direction of the electric field, and when a signal of h is applied, the liquid crystal molecules are oriented perpendicular to the direction of the electric field. If polarizing plates are placed perpendicularly on both sides of the liquid crystal layer, which has a twisted nematic orientation, they will block the light when a toner is applied.
When nah is applied, light is transmitted. FIGS. 4a and 4b show glass substrates constituting a liquid crystal light valve.

11 is a glass substrate 1 provided with a common electrode, and 12 is a glass substrate 2 provided with independent signal electrodes.

13 and 14 are common electrodes, T3 is a metal electrode made of chrome gold or the like, and 14 is a transparent electrode made of indium oxide film or the like.

The light from the light source 1 described above is transmitted only through this transparent electrode. The minute shutter 8 mentioned above corresponds to this.
15 and 16 are signal electrodes, and signals for opening and closing the minute shutter are applied to these electrodes, respectively.

15 is a transparent electrode, and 16 is a metal electrode.

The signal electrodes 15 and 16 and the transparent electrode 14 are 4 in this figure.
Although it is shown in the diagram, the actual number is close to 200.

13 and 15 may have a transparent conductive film above or below the metal electrode.

A liquid crystal light valve is constructed by placing glass substrates 11 and 12 facing each other, sandwiching a liquid crystal layer therebetween, and placing the glass substrates between orthogonal polarizing plates.

Next, FIG. 5 shows the timetable for opening and closing the minute shutter. The horizontal axis is time. 0 level is a state where the shutter is closed, and 1 level is a state where the shutter is open.

A is a case where the shutter is opened continuously, and B is a case where the shutter is closed once. As in example A, even when opening continuously, after opening, the process of closing once and opening again is repeated. If this one cycle time is TI, then the writing time for one dot is . , corresponds to this time. T3 is a signal that always closes, and T2 is a signal that adds an open signal (T in case of A).
2 is an open signal) or a close signal (in the case of B, T2 is a close signal) is applied. Here, the opening signal is a signal with a frequency of nah, and the closing signal is a signal with a frequency of . It is a signal with a frequency of Therefore, FIG. 6 shows applied signals corresponding to the opening and closing of FIGS. 5A and 5B. To T3, a signal of ``M'' is always applied, and to hT2, a ``h'' signal is applied when opening, and a signal ``Ma'' is applied to hT2 when closing. These signals have voltages of V and V as shown in the figure. These signals are applied to each signal electrode 15 shown in FIG.
Each shutter opens and closes by pressing the button. The shutter characteristics using this signal are shown in FIG. Signal C has a waveform that is a combination of A and B. These are me IK rank, nah
These are the results obtained when the frequency was 100 KHz, the temperature was 40° C., and the voltage was 30 V. In this example, the writing time TI could be made as fast as 2 sands. However, there was a problem in that it was not easy to line up and wire 200 circuits capable of outputting signals with a signal voltage V of 30V and a peak-to-peak voltage of 60V. [Objective] The present invention
It overcomes the above problems and has multiple rows of common electrodes,
One signal electrode has a plurality of minute shutters per signal electrode formed by covering the plurality of rows of common electrodes, and the one signal electrode simultaneously and independently opens and closes the plurality of minute shutters. The objective is to realize a liquid crystal shutter using an innovative drive method that reduces the drive voltage by half and the number of drive circuits.

〔Example〕

FIGS. 8a and 8b show an example of a glass substrate constituting a liquid crystal light valve used in the present invention.

This corresponds to FIG. The difference from the example in FIG. 4 is that the 11 glass substrates 1 have two common electrodes 1 and 2 shown at 17 and 18. 14 is a transparent electrode portion.

In b, 15 and 16 are signal electrodes, and 1
6 is a transparent electrode. In the example shown in FIG. 4, the number of signal electrodes was 2,000, but in the present invention, only half, 1,000, is sufficient. FIG. 9 shows the positional relationship between the common electrode and the signal electrode. The transparent portion 16 of the signal electrode corresponds to the transparent electrode 14 of the two common electrodes. This overlapping portion of the transparent electrodes becomes a reduction shutter. The number of minute shutters is 2 for each signal electrode, 200.
It becomes 0. This is the same number as in the example of FIG. Next, the signal applied to this electrode will be explained. FIG. 10 is a schematic diagram of a minute shutter to clarify the explanation.

R1 and R2 are common electrodes 1 and 2. CI to C
4 is a signal electrode. dl to d8 are minute shutters. Diagonally lined minute shutters d3, d4, d5 and d
8 is a closed shutter and other dl, d2, d
6 and d7 are open shutters. The drive method of the present invention uses half the number of signal electrodes shown in FIG. 10 and half the drive voltage, and has almost the same response characteristics as in FIG. 7 for each minute shutter. This is a method that allows you to obtain The signals for opening and closing shown in FIG. 10 are shown in FIGS. 11a, b, and c. Figure 11a shows R-
1 and R-2 are signals applied to the common electrodes RI and R2, respectively. R-1 and R-2 are shown in Figure 6A.
It has the same waveform as the signal shown in , except that the voltage is one-half. TI is the cycle time, T3 is the ner signal, and T2 is the nerh signal. R-1 and R-2
The signals 20 and 21 are in opposite phase. C-1 to C shown in Figure 11b
-4 is a signal applied from CI to the signal electrode C4. At T3, a signal 22 having an opposite phase to 19 is always applied, and at T2, four different signals C-1 to C-4 are applied as described below. First, C-1
, 23 is three-quarters of a phase behind 20',
Furthermore, the signal 24 is a signal with a frequency twice that of the signal 21, which is a quarter phase behind the signal 21. The phases have the relationship shown in the figure. 25 in C-2 is the ner signal. 26 is a signal different from Na1 but having a lower frequency than Nac.

27 of C-3 is a p-h signal having the same phase as 20, and 28 of C-4 is a final h signal having the same phase as 21. As shown in FIG. 11c, the voltages shown at d-1 to d-8 are applied to each minute shutter that applies a signal to each electrode as described above.

A voltage of VI is applied to the portion indicated by 29 at a frequency of NAR.

This signal is applied to all minute shutters, and at this time all shutters are in a closed state. Next 30,
The shutter opens only when the signal 31 or 35 is applied, and otherwise remains closed. As a result, the shutter opens and closes as shown in the schematic diagram of FIG. The response characteristics of light transmission in the case of d-3, d-4, d-5 and d-8 remain completely closed, and d-1 and d-2
, d-6 and d-8 showed almost the same response as shown in FIG. As described above, according to the present invention, the drive voltage can be halved, the number of drive circuits and wiring can be halved, and a high-speed liquid crystal shutter can be obtained.

Next, an example of printing using the liquid crystal light valve according to the present invention will be described below.

Keep the light valve at 40°C, set the driving voltage VI to 15V, set Na1 to IKHz, Meh to 10KHb, and TI to 2.
It was a skin second.

The opening of the minute shutter is 40 squares. A halo lamp having a luminance of approximately 1 million cd' was used as a light source, and zinc oxide sensitized with rose bengal was used as a photoreceptor. After writing, toner development,
Almost 80 Buddhas were transferred and fixed. dots were formed according to the print signal, and almost no variation in dots due to differences in signals was observed, and uniform dots were obtained. [Effect] As described above, the present invention includes a plurality of rows of common electrodes and a plurality of minute shutters per signal electrode formed by one signal electrode covering the plurality of rows of common electrodes. Since the plurality of micro-shutters are simultaneously and independently opened and closed by the one signal electrode, the number of micro-shutter drive circuits and the number of wires can be halved compared to the conventional method.

Furthermore, since a means is provided to apply at least a low frequency signal to the micro-shutter array during one writing period, which is an example of a micro-shutter, the liquid crystal can always return to its initial state within one writing period, so the number of digits increases. Even if signal processing during one write period becomes complicated, stable and constant optical response characteristics can always be obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the configuration of a conventional stamp stealing device. FIG. 2 is a diagram showing a liquid crystal light valve. FIG. 3 is a diagram showing the frequency characteristics of the dielectric anisotropy of the liquid crystal used in the present invention. FIGS. 4a and 4b are diagrams showing a glass substrate constituting a liquid crystal light valve. FIG. 5 is a diagram showing the opening and closing times of the liquid crystal light valve. FIGS. 6 and 7 are diagrams showing signals and light transmission responses of general two-frequency switching. FIGS. 8a and 8b are diagrams showing a glass substrate constituting a liquid crystal light valve used in the present invention. FIG. 9 is a diagram showing the haze polar configuration of the present invention. 1st
Figure 0 is a schematic diagram of the silkworm pole configuration of the present invention. Figure 11a,
b and c are diagrams showing drive signals for the liquid crystal light valve used in the present invention. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 11

Claims (1)

[Claims] 1. In a liquid crystal light valve that is enclosed within a pair of transparent substrates and has a common electrode formed on one of the substrates and a plurality of signal electrodes formed on the other, the plurality of rows of common electrodes and one signal electrode are formed on the other side. It has a plurality of minute shutters per signal electrode formed by covering a plurality of rows of common electrodes, and is characterized in that the plurality of minute shutters are simultaneously and independently opened and closed by the single signal electrode. LCD light bulb.