JPH09265069A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To utilize external light for illumination of a liquid crystal element and to shield light of a light source leaking backward with simple operation by providing a light shielding liquid crystal element provided in the rear of a translucent member and capable of switching a transmission state transmitting the external light to a shield state shielding the external light. SOLUTION: This device is provided with a displaying liquid crystal element 7, a light transmission body 8, the light source 9 and the translucent member 12. The shielding liquid crystal element 13, capable of switching the transmission state transmitting the external light to the shield state shielding the external light, provided in the rear of the translucent member 12. Then, when the external light is obtained sufficiently, the shielding liquid crystal element 13 is brought into the transmission state, and the light source 9 is turned off. Further, when the external light L is not obtained sufficiently such as night, etc., the shielding liquid crystal element 13 is brought into the shield state, and the light source 9 is turned on. Although a part of the light of the light source 9 transmits through the translucent member 12, it is shielded by the shielding liquid crystal element 13 not to be leaked backward.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device using a liquid crystal device, and more particularly to a liquid crystal display device which can utilize external light for illuminating the liquid crystal device.

[0002]

2. Description of the Related Art Conventionally, various liquid crystal display devices using liquid crystal elements have been proposed. The liquid crystal element is a light-receiving type display element that cannot emit light by itself, and for example, the light of a light source is applied to the liquid crystal element to obtain good visibility. Further, a liquid crystal display device utilizing external light such as sunlight has been proposed and is disclosed in, for example, Japanese Utility Model Application Laid-Open No. 57-153381 (see FIG. 5 of the publication). In such a liquid crystal display device, as shown in FIG. 3, a housing 3 for accommodating the liquid crystal element 1 and the semi-transmissive plate 2 is provided with a daylighting window 4, and external light L is emitted from the rear of the liquid crystal element 1. is there. An illumination lamp 5 is attached to the housing 3, and the light of the illumination lamp 5 can be emitted from the front to illuminate the liquid crystal element 3 at night.

[0003]

However, when the illumination lamp 5 is turned on, there is a problem that light passes through the semi-transmissive plate 2 and leaks rearward. Therefore, the lid portion 6 that can open and close the lighting window 4 is provided. It was provided in the housing 3. That is, the external light L
Is sufficiently obtained, the illumination lamp 5 is turned off and the lid 6
So that the external light L is emitted from the rear of the liquid crystal element 3, and when the external light L is insufficient at night or the like,
The lid 6 is closed and the illumination lamp 5 is turned on to illuminate the liquid crystal element 1 from the front. This liquid crystal display device uses external light L
On the other hand, there is an advantage that the light of the illumination lamp 5 can be switched and used, but there is a problem that the operation of opening and closing the lid 6 is troublesome. The present invention provides a liquid crystal display device that can use external light for illuminating a liquid crystal element and can block the light of a light source leaking backward by a simple operation.

[0004]

In order to solve the above-mentioned problems, the present invention provides a display liquid crystal element, a light guide provided behind the display liquid crystal element, and light to the light guide. A light source, and a semi-transmissive member provided behind the light guide,
A light-shielding liquid crystal element provided behind the semi-transmissive member and capable of switching between a transmissive state of transmitting external light and a light-shielding state of shielding the external light.

Further, according to the present invention, the display liquid crystal element, the light guide, the light source, the semi-transmissive member, and the light shielding liquid crystal element are housed to form a light-collecting window corresponding to the light shielding liquid crystal element. And a pedestal rotatably provided on the case.

Further, according to the present invention, there is provided a reflecting member which is provided on the pedestal and reflects the external light toward the lighting window.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION A light-shielding liquid crystal element capable of switching between a transmission state in which the external light L is transmitted and a light-shielding state in which the external light L is blocked.
By providing 13, the external light L can be used to illuminate the display liquid crystal element 7, and the light of the light source 9 leaking backward can be blocked by a simple operation.

Further, a case 15 accommodating the display liquid crystal element 7, the light guide 8, the light source 9, the semi-transmissive member 12 and the light shielding liquid crystal element 13, and a pedestal 20 rotatably provided in the case. By providing the above, the display liquid crystal element 7 can be adjusted to a desired angle.

Further, since the pedestal 20 is provided with the reflecting member 22 for reflecting the external light L toward the daylighting window 17 side, the external light L applied to the front liquid crystal element 7 can be increased.

[0010]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a sectional view of a main part, and FIG. 2 is an exploded perspective view.

Reference numeral 7 denotes a display liquid crystal element. This display liquid crystal element 7 is of a so-called dot matrix type in which pixels 7a are arranged in a matrix, and various characters are formed by making a desired pixel 7a transparent or non-transparent. And shapes can be displayed. Reference numeral 8 denotes a light guide, and this light guide 8 is a plate-shaped member made of a light-transmitting resin such as acrylic. The light guide 8 is provided behind the display liquid crystal element 7. 9 is a cold cathode tube (light source), a switch
It can be turned on by turning on 10. The cold cathode tubes 9 are arranged along the side surfaces of the light guide 8 and supply light to the light guide 8. 11 is a reflector, which is a cold cathode tube 9
Light is reflected to the light guide 8 side. Reference numeral 12 is a semi-transmissive plate (semi-transmissive member), and the semi-transmissive plate 12 is a sheet-shaped member made of a resin such as polycarbonate. The semi-transmissive plate 12 is provided behind the light guide 8. Reference numeral 13 is a light-shielding liquid crystal element, and this light-shielding liquid crystal element 13 is a TN type liquid crystal element in which a TN (twisted nematic) type liquid crystal is sealed between a pair of glass substrates. The light-shielding liquid crystal element 13 can switch the segment 13a between the transmission state and the light-shielding state by turning the switch 14 OFF or ON. Segment 13
a is slightly larger than the lighting window described later.

Reference numeral 15 denotes a case, which accommodates the display liquid crystal element 7, the light guide 8, the cold cathode tube 9, the reflector 11, the semi-transmissive plate 12 and the light shielding liquid crystal element 13. Reference numeral 16 is a display window, and this display window 16 is an opening formed on the front surface side of the case 15. The display window 16 is formed corresponding to the display liquid crystal element 7. Reference numeral 17 denotes a daylighting window, and this daylighting window 16 is an opening formed on the rear surface side of the case 15. The lighting window 16 is formed corresponding to the light-shielding liquid crystal element 13. In addition, transparent panels 18 and 19 are fitted in the display window 16 and the daylighting window 17, respectively. 20 is a pedestal,
The pedestal 20 is pivotally supported on the case 15 by a rotation shaft 21 and is rotatably provided on the case 15, so that the display liquid crystal element 7 can be adjusted to a desired angle. Reference numeral 22 is a reflecting mirror (reflecting member), which can reflect external light L such as sunlight and indoor illumination light to the side of the daylighting window 17. The reflecting mirror 22 is attached and provided on the upper surface of the pedestal 20.

When sufficient external light L is obtained, the switches 10 and 14 are turned off, the light-shielding liquid crystal element 13 is set to the transmissive state, and the cold cathode tube 9 is turned off. The external light L is directly or reflected by the reflecting mirror 22 to enter through the daylighting window 17, passes through the light-shielding liquid crystal element 13, and is emitted from the rear of the display liquid crystal element 7. Also, if there is not enough external light at night,
The switches 10 and 14 are respectively turned on to bring the light-shielding liquid crystal element 13 into a light-shielding state, and the cold cathode tube 9 is turned on. The light of the cold-cathode tube 9 is diffusely reflected inside the light guide 8 and is reflected forward by the semi-transmissive plate 12 to be applied to the display liquid crystal element 7. Further, a part of the light of the cold cathode tube 9 is transmitted through the semi-transmissive plate 12, but is blocked by the light-shielding liquid crystal element 13 and does not leak rearward.

According to this embodiment, the external light L and the cold cathode tube 9 are used.
It is possible to use the light for switching the display light and illuminating the display liquid crystal element 7. Further, the light-shielding liquid crystal element 13 can be put into a light-shielding state by a simple operation of turning on the switch 14 to prevent the light of the cold cathode tube 9 from leaking backward. Also, case 15
The display liquid crystal element 7 can be adjusted to a desired angle by providing the pedestal 20 that is rotatably provided.
In addition, by providing the pedestal 20 with the reflection mirror 22 that reflects the external light L toward the daylighting window 17 side, the external light L emitted to the display liquid crystal element 7 can be increased.

The light-shielding liquid crystal element 13 of the present embodiment is in a light-shielding state when the switch 14 is ON. However, the light-shielding liquid crystal element 13 is in a light-shielding state when the switch 14 is OFF, for example. It may be in a transmissive state when is ON. Further, the light-shielding liquid crystal element 13 is a TN type liquid crystal element, but may be, for example, an NCAP type liquid crystal element in which liquid crystal is microcapsulated and dispersed in a polymer matrix.

In this embodiment, the external light L and the cold cathode tube 9 are used.
Is used to illuminate the display liquid crystal element 7, but the cold cathode tube 9 may be turned on even when the external light L is sufficiently obtained, and the display liquid crystal element 9 is further It can be illuminated brightly. At this time, even if the light of the cold-cathode tube 9 leaks backward, no problem occurs because the surroundings are bright.

Further, although the switches 10 and 14 of this embodiment are individually operated, the light-shielding liquid crystal element 13 and the light source 9 can be operated in conjunction with one switch by using a relay circuit or the like. You may do it.

In this embodiment, the semi-transmissive plate 12 is used, but a semi-transmissive layer (semi-transmissive member) may be provided by printing semi-transparent ink on the rear surface of the light guide 8. good.

[0019]

According to the present invention, a display liquid crystal element, a light guide provided behind the display liquid crystal element, a light source for supplying light to the light guide, and a light guide provided behind the light guide. A semi-transmissive member provided, and a light-shielding liquid crystal element that is provided behind the semi-transmissive member and is switchable between a transmissive state for transmitting external light and a light-shielding state for shielding the external light. External light can be used to illuminate the liquid crystal display device, and the light from the light source leaking backward can be blocked by a simple operation.

Further, according to the present invention, the display liquid crystal element, the light guide, the light source, the semi-transmissive member, and the light shielding liquid crystal element are housed to form a daylighting window corresponding to the light shielding liquid crystal element. It has a case and a pedestal rotatably provided on the case, and the display liquid crystal element 7 can be adjusted to a desired angle.

Further, according to the present invention, a reflection member provided on the pedestal for reflecting the external light to the side of the lighting window is provided, and the external light L radiated to the front liquid crystal element 7 can be increased. .

[Brief description of drawings]

FIG. 1 is a partial sectional view showing an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the embodiment.

FIG. 3 is a sectional view showing a conventional example.

[Explanation of symbols]

 7 Liquid crystal display element 8 Light guide 9 Cold cathode tube (light source) 12 Semi-transmissive plate (semi-transmissive member) 13 Light-shielding liquid crystal element 15 Case 17 Lighting window 20 Pedestal 22 Reflector (reflecting member)

Claims (3)

[Claims] 1. A display liquid crystal element, a light guide provided behind the display liquid crystal element, a light source for supplying light to the light guide, and a semi-display provided behind the light guide. A liquid crystal display device comprising: a transmissive member; and a light-shielding liquid crystal element that is provided behind the semi-transmissive member and can be switched between a transmissive state in which external light is transmitted and a light-shielded state in which the external light is blocked. 2. A case in which the display liquid crystal element, the light guide, the light source, the semi-transmissive member, and the light shielding liquid crystal element are accommodated and a daylighting window corresponding to the light shielding liquid crystal element is formed. The pedestal rotatably provided in the case, The liquid crystal display device according to claim 1. 3. The liquid crystal display device according to claim 2, further comprising a reflection member provided on the pedestal and configured to reflect the external light toward the lighting window.