JPS5981622A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To obtain a liquid crystal display device having a light display part and a nondisplay part nonexposing a film by using a polarizing plate formed by applying a polarizer having a specified transmittance of a simple substance onto a polarizer having a specified orthogonal transmittance. CONSTITUTION:The characteristics 1 of an incandescent tungsten bulb are low in specific intensity of the light in the region of short wavelength, but compartively high in that in the 600-700nm region. In the nondisplay part, the transmittance of light in 570-700nm wavelengths is greatly lowered, but the light in this region is allowed to reach the surface of the photosensitive emulsion of a film without decrease of the light. Therefore, the light from a light source can be effectively utilized, and at the same time, the film can be prevented from being exposed to the unnecessary light from the nondisplay part. Consequently a polarizer having an absorption region in 400-650nm wavelengths used for the conventional liquid crystal display device is used for the first polarizer, and the second polarizer having 570-700nm wavelength absorption region is applied onto the first polarizer, and contrast ratio is improved in the long wavelength region.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid crystal display element. More specifically, the present invention relates to a liquid crystal display element that is provided between a photographic film and a light source and used for recording information such as a date on the film.

Liquid crystal display elements have been widely accepted in the market due to their low voltage drive and low power consumption, and are being widely used in devices such as wristwatches. In addition, by combining the ability to display various displays with electrode patterns and the function as a light shutter,
The application of this technology to recording information such as the date of shooting on photographic film is about to expand, and this is a field with great expectations. In this J: Una record on photographic film,
Although LEDs have been used in the past, they are being replaced by liquid crystal display devices due to their cost, display color, and power consumption.

When recording the date, etc. on photographic film, there are two methods: one is to record the date from the front of the film in the same way as normal shooting, and the other is to expose it to a certain emulsion, but the latter method is the simplest and requires fewer modifications to the camera body. It is widely used because of its low cost. FIG. 3 is an explanatory diagram of the latter method, in which the light emitted from the light source 3 passes through the liquid crystal display element 4, and the shape of the pattern formed there is projected onto the photosensitive emulsion surface 6 through the film base material 5. The imprinted area becomes a double copy of the image taken from the front of the film. In order to reduce the effect on images taken from the front, it is common to use a liquid crystal display element that, unlike a normal liquid crystal display element, allows light to pass through in the display area and not in the non-display area.

Conventionally used liquid crystal display elements have the following drawbacks from the perspective of recording on film. That is, since the brightness changes depending on the subject in the double copy area, it is necessary to brighten the light source behind the liquid crystal display in order to obtain a clear imprint of the date, etc. even in bright conditions. However, conventional liquid crystal displays have the disadvantage that when the light source is made brighter, the absolute brightness of the non-display area increases, and the non-display area appears on the film in a dark subject area. For this reason, the present invention had to be implemented by darkening the light source and sacrificing the quality of the imprint in bright areas.The present invention considers the characteristics of the light source and the characteristics of photographic film, and solves the drawbacks of conventional liquid crystal display elements. The present invention provides a removed liquid crystal display element.

The present invention will be described in detail below using explanatory diagrams.

FIG. 2 shows the wavelength characteristics of a tungsten bulb used as a light source and a film base material. Looking at characteristic 1 of the tungsten light bulb, while the specific intensity of light is small at short wavelengths, the specific intensity from 600 rmn to 700 rpm is quite large. Furthermore, when focusing on the light transmittance 2 of the film base material, it can be seen that light is more easily transmitted on the long wavelength side. These two characteristics di
When imprinting a date, etc. from the rear surface of a film from the f-line, it is clear that the light reaching the photosensitive emulsion is biased considerably towards the longer wavelength side. However, since conventional LCD panels have the characteristic that the contrast ratio is highest in the vicinity of 500 mm to 550 m+n, the long wavelength light that is actually received by the photosensitive emulsion leaks out in the non-display areas. So it became.

The purpose of the present invention is to improve this drawback of conventional liquid crystal display elements and to provide an excellent liquid crystal display in which the display area is bright and the non-display area is not reflected in the film by making the most effective use of the light incident on the film. The purpose is to provide devices.

That is, in the method according to the present invention, attention is paid to the long wavelength side of light, and in the non-display area, 700 nn from this 570 cylinder is
The transmittance of light in this wavelength range is significantly lowered, and in the display area, light in this wavelength range is allowed to reach the film emulsion surface without being reduced. Therefore, the light from the light source can be used effectively and unnecessary reflections of non-display areas can be prevented. For this purpose, in the present invention, a polarizing plate used in a conventional liquid crystal display element is used as a first polarizing body, and a second polarizing plate having an absorption range from a light wavelength of 570 mm to 700 mm is added thereon. By overlapping the panels, the contrast ratio in the long wavelength range, which has been a drawback of conventional liquid crystal displays, is significantly improved. This second polarizer is generally sometimes referred to as a color polarizer, and the one used in the present invention is a blue or rutted color polarizer. A color polarizing plate absorbs part of the wavelength range of linearly polarized light whose vibration direction is parallel to its absorption axis, and transmits most of the linearly polarized light whose vibration direction is perpendicular to its absorption axis. It has the property of causing Used in a twisted nematic liquid crystal display element, the color polarizing plate is designed so that in the non-display state, light with a vibration direction parallel to the absorption axis is incident, and in the display state, light with a vibration direction perpendicular to the absorption axis is incident. Then, in the absorption wavelength range of the color polarizing plate, the non-display area becomes darker, and the brightness of the display area can be prevented from being impaired.

In the present invention, the absorption range of the color polarizing plate is adjusted from the light wavelength of 570 to 70, taking into account the characteristics of the film and light source.
It is set between 0 m.

The method according to the invention can also be applied to conventional color liquid crystal display confectionery, in which case it is possible to enhance the vividness of the colors without significantly impairing the brightness. or,
Either the upper surface or the lower surface may be used for only one side, or may be used for both sides. When used on both sides, the color polarizing plate used on the top side and the absorption range on the bottom side can be different. In this case, various absorption wavelength ranges can be selected depending on the purpose of use. It is possible.

Hereinafter, specific examples according to the present invention will be described.

Example 1. As the first polarizer, type LO2-80 manufactured by MAW was used.
-1BS is prepared, and the same type 5 is used as the second polarizer.
OG-188 was prepared, and the two were laminated together so that the absorption axis of the first polarizer and the absorption axis of the second polarizer were parallel to each other. The polarizing plates thus produced were attached to both sides of a twisted nematic liquid crystal cell so that the absorption axes of the upper and lower polarizing plates were parallel to each other. At this time, make sure that the absorption axis of the polarizing plate is parallel to the alignment direction of liquid crystal molecules on either the upper or lower substrate of the liquid crystal cell. As a result of measuring the contrast ratio with respect to the wavelength of light for the liquid crystal display thus produced, the characteristics shown in Figure @1 were obtained. Furthermore, even when characters were actually imprinted onto the film, it was confirmed that almost no non-displayed areas were visible. This was reconfirmed by the fact that even when the brightness of the tungsten light bulb used was increased, there was almost no reflection of the non-displayed areas.

[Brief explanation of the drawing]

FIG. 1 shows the characteristics of the contrast ratio with respect to the wavelength of light of a liquid crystal display element in an example according to the present invention. FIG. 2 is an explanatory diagram of the characteristics of the specific intensity (1) of a tungsten bulb with respect to the wavelength of light and the transmittance (2) of the film base material. FIG. 3 is an explanatory diagram of a method for imprinting characters on a film, in which numeral 6 indicates a light source, 4 a liquid crystal display element, 5 a film base material, and 6 a photosensitive emulsion of the film. Amendment to Procedures for Diagram 5 of the 11th Rebellion (Voluntary) 1 Indication of the case Patent Application No. 189610 of 1989 21 Ming liquid crystal display device: 3 Relationship with the case of the person making the h0 correction Applicant 4 Representative Friend 5 Supplement J ■: Increased number of inventions due to 6, Supplementary written amendment to the subject specification procedure (voluntary) 1. Amend the scope of the claims as shown in the attached sheet. 2, page 4 of the specification, line 9, page 4, line 10, month, page 4, line 17, month, page 5, line 8, page 5, line 16, month, page 6, line 15 month. °Compensate pressure. Claims above In a liquid crystal display element consisting of a liquid crystal cell in which liquid crystal is sealed between two electrode substrates, and polarizing plates provided on the top and bottom surfaces of the liquid crystal cell, the polarizing plate protects the light. Wavelength 400 to 650
A liquid crystal display element characterized by laminating a first polarizing material having a single transmittance of 43% or less and a second polarizing material having a value of half the wavelength ratio of light or less. .

Claims (1)

[Claims] In a liquid crystal display element consisting of a liquid crystal cell in which liquid crystal is sealed between two electrode substrates, and polarizing plates provided on the upper and lower surfaces of the liquid crystal cell, the polarizing plates
The first polarizer has a single transmittance of 43% or less over the zero cylinder, and the orthogonal transmittance from the light wavelength of 570 mm to 70.0 mm is half the orthogonal transmittance from 400 to 550' + nm. A liquid crystal display element characterized in that it is formed by laminating a second polarizer having the following values.