JPH0121336Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a device that displays various displays using liquid crystal, and in particular, it has the function of a reflective liquid crystal display device and is used for vehicle instruments such as automobiles. The present invention relates to a liquid crystal display device suitable for use as a display device.

[Conventional example]

A liquid crystal cell is constructed by sandwiching a liquid crystal, such as a field-effect nematic liquid crystal, between two transparent electrode plates with electrodes of a predetermined shape formed on opposing surfaces, and the molecular alignment direction of the liquid crystal is controlled according to the voltage applied to the electrodes. A liquid crystal display device including a liquid crystal display element that performs display according to the shape of the electrode by controlling the transmission of light in relation to the polarization axis of a polarizing member provided at least in front of the liquid crystal cell. Kaisho 50-31854, same 52
This is disclosed in publications such as No. 79694 and No. 56-22468, and has the advantage of being thinner and consuming less current.

In particular, a member having a reflective function such as a reflective plate or a semi-transparent reflective plate is disposed on the rear surface of the liquid crystal cell,
Transflective liquid crystal display devices, which include constant reflective or transmissive properties, are suitable for use as display devices for vehicle instruments because they can utilize external light (sunlight).

FIG. 1 is a schematic sectional view showing a general conventional example.

A liquid crystal display element is arranged inside the instrument case 1, and this liquid crystal display element has a reflector plate 2,
It has a rear polarizing member 3 disposed in front of the polarizing member 3, and a liquid crystal cell 4 disposed in front of the polarizing member 3. Transparent electrodes 7 and 8 each having a predetermined shape are deposited on opposing surfaces of the cell 4, and a field-effect nematic liquid crystal 9 is sealed between the electrodes in a twisted arrangement with the axial direction twisted at 90 degrees. In this example, a front polarizing member 10 whose polarization axis is different from that of the rear polarizing member 3 by 90 degrees is provided.

The instrument case 1 has a cylindrical hood part 11 extending forward of the front polarizing member 10 so as to cover the front outer periphery of the front polarizing member 10 . The hood part 11 has a facing member 12 that covers and hides it from the front and forms letters, symbols, etc. on the front side, and a transparent cover 13 is attached to the front opening of the hood part 11. In the upper part of the hood part 11,
The lamp 14, which is a light source for illumination, is attached to a lamp cover 15.
It is attached in an inclined state toward the liquid crystal cell 4 side through the. The light from this lamp 14 is irradiated onto the liquid crystal cell 4 side through an illumination opening 16 formed in the upper part of the hood part 11.

In such a configuration, external light and light from the lamp 14 pass through the front polarizing member 10 and pass through the liquid crystal 9 as polarized light with a unidirectional component. Here, electrodes 7, 8
If there is a potential difference between the electrodes 7 and 8, the light passing through this part will not have its polarization axis twisted by the liquid crystal 9, and there will be no potential difference between the electrodes 7 and 8. Since the liquid crystal 9 is twisted, the light that passes through the unformed portion has its polarization axis twisted by 90 degrees. Since the polarization axis of the rear polarizing member 3 is different from the polarizing axis of the front polarizing member 10 by 90 degrees, the former light cannot pass through the rear polarizing member 3, and the latter light cannot pass through the rear polarizing member 3. Since the side polarizing member 3 can be transmitted, the electrodes 7,
The liquid crystal cell 4 looks opaque only in the part where the potential difference of 8 is generated, and the other part comes out of the liquid crystal cell 4 almost unaffected by the liquid crystal 9, so it looks bright, that is, a black image on a white background is obtained. It turns out. Note that if the polarization axes of the front polarizing member 10 and the rear polarizing member 3 are aligned in parallel, a white image on a black background will be obtained.

[Problem that the invention attempts to solve]

Incidentally, the external light and the light from the lamp 14 have multidirectional components, and directly strike the facing member 12 of the hood portion 11. On the other hand, since the light passing through the front polarizing member 10 is cut into a unidirectional component, the amount of light passing through the liquid crystal cell 4 is reduced.

Therefore, the characters, symbols, etc. provided on the facing member 12 appear to shine more brightly than the brightly visible portions of the background or image caused by the twisting action of the liquid crystal 9. Since outside light is originally strong light, the difference in brightness is so small that it hardly affects visual recognition when illuminated with outside light, such as in the daytime, but it becomes large when the light from the lamp 14 is used, such as at night, and the brightness difference is large when the light from the lamp 14 is used, such as at night. There was a problem where only 12 appeared to be illuminated.

[Purpose of the invention] This invention was devised by focusing on the problems of the conventional example, and it is possible to arrange the liquid crystal display element and the end panel material on the front side in close proximity to each other. An object of the present invention is to provide a liquid crystal display device illuminated from the front with light from a light source, which can improve the feeling of non-uniform brightness when the light source is illuminated.

[Summary of the idea]

In order to achieve the above object, this invention constructs a liquid crystal cell by sandwiching a liquid crystal between two transparent electrode plates with electrodes of a predetermined shape formed on opposing surfaces, and at least the front surface of this liquid crystal cell is provided with polarized light. Further, a member having a reflective function is disposed on the rear surface of the liquid crystal cell, and the direction of molecular arrangement of the liquid crystal is changed in accordance with the application of voltage to the electrode, thereby controlling the transmission of light from the relationship with the polarization axis of the polarizing member. A liquid crystal display element that is controlled to display a display according to the shape of the electrode, and an endpaper that is located in front of the liquid crystal display element to make the liquid crystal display element visible from the front and that forms characters, symbols, etc. on the front surface. and a light source that illuminates the liquid crystal display element and the facing member from the front, wherein a polarizing axis of the polarizing member of the liquid crystal display element is provided between the liquid crystal display element, the facing member, and the light source. A polarizing member is provided with the polarizing axis aligned so that it is parallel to the polarizing member.

〔Example〕

Hereinafter, an embodiment of this invention will be described based on FIGS. 2 and 3, and the same or equivalent parts as in the conventional example shown in FIG.

An illumination opening 16 formed in the upper part of the cylindrical hood part 11, which is located at the front of the instrument case 1 and has a facing member 12 on which characters, symbols, etc. are formed, is provided with a front polarized light of the liquid crystal display element. Part 1
Polarizing member 17 with the polarization axis aligned parallel to 0
is attached, and the light from the lamp 14 is polarized by the polarizing member 17.
When the light passes through the light, only a unidirectional component is irradiated toward the liquid crystal display element and the facing member 12.

With such a configuration, the light from the lamp 14 is
First, the light becomes a unidirectional component by the polarizing member 17,
It advances to the liquid crystal display element side and illuminates characters, symbols, etc. used for display on the liquid crystal display element and provided on the facing member 12.

First, let us consider the light that performs display on the liquid crystal display element. The light that reaches the front polarizing member 10 is polarized so that it can be transmitted through the front polarizing member 10 by the polarizing member 17 whose polarizing axis is parallel to that of the front polarizing member 10, so that it is not cut off as in the conventional case. In this state, the light reaches the liquid crystal cell 4, and thereafter a predetermined display is performed by the same operation as in the conventional example (see FIG. 3). At this time, the amount of light passing through the liquid crystal cell 4 is almost the same as in the conventional case, and the contrast between the light-transmitting part and the non-transmitting part is almost the same as in the conventional case.

Next, the illumination of the facing member 12 will be considered. Conventionally, the facing member 12 was directly illuminated by light with multidirectional components, but with this structure, the polarizing member 17 irradiates the light with a reduced amount of polarization, and in this case, the facing member 12 is illuminated with only one light beam. There is no problem even if the light is polarized with only the directional component; the only difference is that the illuminance is lower than in the past, and the facing member 12
Only the development that shines brighter than others is avoided.

[Effect of idea]

In this way, this invention constructs a liquid crystal cell by sandwiching a liquid crystal between two transparent electrode plates with electrodes of a predetermined shape formed on their opposing surfaces, and also includes a polarizing member or a polarizing member on at least the front surface of the liquid crystal cell. A member having a reflective function is disposed on the rear surface, and the molecular arrangement direction of the liquid crystal is changed according to the voltage applied to the electrode, and the transmission of light is controlled from the relationship with the polarization axis of the polarizing member. a liquid crystal display element that performs display according to the shape of the liquid crystal display element; a facing member that is located in front of the liquid crystal display element to make the liquid crystal display element visible from the front and forms characters, symbols, etc. on the front surface; In a liquid crystal display device having a display element and a light source that illuminates the facing member from the front, a space between the liquid crystal display element, the facing member, and the light source is such that the light source is parallel to the polarization axis of the polarizing member of the liquid crystal display element. It is equipped with a polarizing member whose polarizing axes are aligned, and therefore, it is possible to limit the illumination of the facing member without reducing the amount of light provided for display on the liquid crystal display element, so that it is possible to limit the illumination of the facing member. When viewed from above, the overall brightness balance is maintained appropriately, suppressing eye fatigue caused by excessive lighting in some areas, and significantly improving the visual effect and usage environment. In particular, when using a light source for lighting at night, etc., the display can improve the sense of uneven brightness, and if applied to liquid crystal display devices used as display devices for vehicle instruments, it will quickly and reliably provide the necessary information for driving. This makes it possible to recognize information such as information, and to concentrate more on the surrounding environment, allowing for more accurate vehicle operation, which greatly contributes to traffic safety in light of recent traffic conditions.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view showing the structure of a conventional liquid crystal display device, FIG. 2 is a schematic sectional view showing the structure of a liquid crystal display device according to an embodiment of this invention, and FIG. 3 is a display example of the same liquid crystal display device. FIG. 1... Instrument case, 2... Member having a reflective function,
4...Liquid crystal cell, 9...Liquid crystal, 10...Polarizing member, 12
... facing member, 14... lamp, 17... polarizing member.

Claims (1)

[Scope of utility model registration request] A liquid crystal cell is constructed by sandwiching a liquid crystal between two transparent electrode plates with electrodes of a predetermined shape formed on opposing surfaces, and at least a polarizing member is provided on the front surface of this liquid crystal cell, and a reflective function is provided on the rear surface of the liquid crystal cell. A display according to the shape of the electrode is provided by disposing a member having the structure and changing the molecular arrangement direction of the liquid crystal in accordance with voltage application to the electrode, controlling light transmission from the relationship with the polarization axis of the polarization member, and displaying according to the shape of the electrode. a liquid crystal display element, a facing member located in front of the liquid crystal display element to make the liquid crystal display element visible from the front and forming characters, symbols, etc. on the front surface; In a liquid crystal display device having a light source that illuminates from the front, a polarizing member having a polarizing axis aligned parallel to a polarizing axis of the polarizing member of the liquid crystal display element between the liquid crystal display element, the facing member, and the light source. A liquid crystal display device characterized by being provided with.