JPH0862569A - Liquid crystal device - Google Patents

Abstract

PURPOSE: To obtain a liquid crystal device in which the display part itself is provided with the function of the light receiving part of a solar battery by forming liquid crystal parts and a driver circuit on a semiconductor substrate provided with the function of the solar battery. CONSTITUTION: The liquid crystal device constituted so as to arrange the liquid crystal parts on the semiconductor substrate provided with the function of the solar battery is used as the display part. A liquid crystal LC becomes transparent when it is driven (a voltage is applied to transparent electrodes 6, 7), and an incident beam L arrives at the substrate surface. This part becomes a relatively bright pixel, and simultaneously the characteristics of the solar battery on the substrate appears, and electromotive force Eb occurs on this part. The liquid crystal LC becomes opaque under the state of non-driven, and the relatively dark pixel is displayed. Although the electromotive force hardly occurs on the part, electric power is stored temporarily in a storage battery so that the power generation amount of the solar battery in the whole liquid crystal device takes effect as its time integration. Since the liquid crystal part generates electric power as the solar battery on the transparent part, the particular solar battery is eliminated, or is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal device, and more particularly to a liquid crystal device capable of generating all or part of its driving power.

[0002]

2. Description of the Related Art In recent years, there has been a great interest in clean energy and energy saving from the standpoint of environmental protection, and a solar cell as a power source has appeared in not only a calculator but also a writer. Here, the solar cell generates electric power in proportion to its light receiving area, and a sufficient space is required on the upper surface of the casing. However, there is a strong demand for visualization of information devices, and it is becoming difficult to secure a sufficient light-receiving area because the display section tends to be large.

[0003]

SUMMARY OF THE INVENTION The present invention was devised to solve such conventional problems, and an object thereof is to provide a liquid crystal device in which the display section itself has a function of a light receiving section of a solar cell. And

[0004]

In the liquid crystal device according to the present invention, a liquid crystal part and a driver circuit are formed on a semiconductor substrate having the function of a solar cell, and power is generated as a solar cell in a transparent portion of the liquid crystal part. It is a thing.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of a liquid crystal device according to the present invention will be described with reference to the drawings.

FIG. 1 shows a portable information device 1 provided with a display unit composed of a liquid crystal display, for example, an electronic book (a document of a book, graphic data having the same image as the book, and displayed in page units). A display unit 3 made of a liquid crystal display is provided over substantially the entire surface of the casing 2. If such a large display unit is provided, the solar cell mounting space cannot be secured.

Therefore, as shown in FIG. 2, a liquid crystal device in which liquid crystal parts 5 are arranged on a semiconductor substrate 4 having the function of a solar cell is used as a display unit 3.

The liquid crystal device is constructed as shown in FIG.
A P layer is formed on the base of the type semiconductor. This is a structure as a solar cell, and when the light ray L enters the P layer, P
Electromotive force Eo is generated between the layers and the N layer. The electromotive force Eo is output from the output wirings L1 and L2.

The liquid crystal part 5 is formed by enclosing a liquid crystal LC between transparent electrodes 6 and 7 made of indium-tin oxide or the like and sealing the periphery with a sealing material 8. The transparent electrode 6 on the substrate side is an electric field. The drain D of the effect transistor Tr is connected via the metal portion M1. On the other hand, the electrode 7 is connected to the drive wiring DL1 (power supply side) via the metal portion M2, and the source S of the transistor Tr is connected to the drive wiring DL2 (ground side). The gate G of the transistor Tr is connected to the control wiring CL (FIG. 4).

FIG. 4 shows a drive circuit including the transistor Tr, and the liquid crystal parts 5 are shown in a smaller number than they actually are. The drive wiring DL1 is connected to the decoder 9, the drive wiring DL2 is connected to the decoder 10, and the control wiring CL is connected to the power supply Vdd. In such a configuration, the Nth control wiring CL (shown with N attached)
Is set to a high level and the n-th driving wiring DL1 (shown with n) is grounded, the liquid crystal part 5 located at the intersection of these wirings is driven. Therefore, the decoders 9 and 10
If an address signal (not shown) is input to, only the desired liquid crystal part 5 can be driven.

The liquid crystal LC becomes transparent when driven (voltage is applied to the transparent electrodes 6 and 7), and the incident light L reaches the surface of the substrate. This part becomes a relatively bright pixel,
At the same time, the characteristics of the solar cell in the substrate are exposed, and an electromotive force Eb is generated in this portion. In the non-driving state, the liquid crystal LC becomes opaque and relatively dark pixels are displayed. Almost no electromotive force is generated in this portion, but the electric power is once stored in the storage battery 11 so that the power generation amount of the solar cell in the entire liquid crystal device is effective as its time integration (FIG. 5).

FIG. 5 is a circuit diagram showing the power supply system of the liquid crystal device. The solar cells (indicated by SB in FIG. 5) are connected in parallel via the diode DS to the DC / DC converter 12.
And is adjusted to a predetermined DC voltage Vo. DC /
The output of the DC converter 12 is connected to the switch circuit 13, and the switch circuit 13 is further connected in parallel with the input obtained by converting the AC voltage into the DC voltage Vo by the switching regulator 14. When the output (power generation amount) on the solar cell side is insufficient, the switch circuit 13 detects the voltage drop, shuts off the output of the DC / DC converter, and connects the output of the switching regulator to the storage battery 11. The storage battery 11 is connected to the switch circuit 13 via the current limiting resistor Rb, and when the electromotive force Eb of the storage battery 11 is reduced, charging is performed with a charging current of Ich = (Vo-Eb) / Rb. When this charging progresses and the electromotive force Eb of the storage battery 11 increases, Ich automatically decreases, and a so-called trickle charge is made to compensate for spontaneous discharge.

The output of the storage battery 11 is used to drive a liquid crystal device or is supplied to other electronic circuits in the portable information equipment 1. With this, all or part of the electric power can be supplied by the power generation function of the display unit itself without providing a separate solar cell. Incidentally, it is of course possible to add an auxiliary solar cell or to use other power sources together, if necessary.

In the portable information device 1 of FIG. 1, reference numeral 15
Is a finger recess, reference numeral 16 is a power supply terminal for connecting the output of the switching regulator, reference numerals 17 and 18 are page break operation buttons, and reference numerals 19 and 20 are a power button and a fast-forward button, respectively.

[0015]

In the liquid crystal device according to the present invention, the liquid crystal parts and the driver circuit are formed on the semiconductor substrate having the function of the solar cell, and power is generated as the solar cell in the transparent part of the liquid crystal part. The device itself can be used as a light receiving part of the solar cell, and the use of a separate solar cell can be eliminated or reduced.

[Brief description of drawings]

FIG. 1 is a front view showing a portable information device using a liquid crystal device according to the present invention.

FIG. 2 is a perspective view showing the liquid crystal device.

FIG. 3 is a vertical sectional view showing one embodiment of a liquid crystal device according to the present invention.

FIG. 4 is a block diagram showing a drive circuit of the same embodiment.

FIG. 5 is a block diagram showing a power supply system of the embodiment.

[Explanation of symbols]

 1 ・ ・ ・ Portable information equipment 2 ・ ・ ・ Casing 3 ・ ・ ・ Display 4 ・ ・ ・ Semiconductor substrate 5 ・ ・ ・ Liquid crystal parts 6, 7 ・ ・ ・ Transparent electrode 8 ・ ・ ・ Sealing material 9, 10 ・ ・ ・Decoder 11 ・ ・ ・ Storage battery 12 ・ ・ ・ DC / DC converter 13 ・ ・ ・ Switch circuit 14 ・ ・ ・ Switching regulator 15 ・ ・ ・ Finger-holding recess 16 ・ ・ ・ Power supply terminal 17, 18 ・ ・ ・ Operation button 19・ ・ ・ Power button 20 ・ ・ ・ Fast forward button LC ・ ・ ・ Liquid crystal parts Tr ・ ・ ・ Transistor D ・ ・ ・ Drain S ・ ・ ・ Source G ・ ・ ・ Gate CL ・ ・ ・ Control wiring DL1, DL2 ・ ・ ・Drive wiring M1, M2 ... Metal part L ... Ray

Claims (1)

[Claims] 1. A P layer is formed on both sides of an N-type semiconductor substrate, and a plurality of liquid crystal parts are arranged on the P layer of the first surface of the substrate, and adjacent to each liquid crystal part on the P layer of the first surface. A field effect transistor is formed by connecting the drive wiring to the liquid crystal part through the transistor, and the control wiring is connected to the gate of the field effect transistor.
A liquid crystal device in which output wirings are connected to the layer and the N layer, and a light ray transmitted through the liquid crystal part is incident on the back side of the liquid crystal part on the first surface of the base.