JPH05173123A - Liquid crystal display device - Google Patents

Abstract

PURPOSE:To provide the liquid crystal display device which can be increased in the brightness in the viewing direction of a user without increasing the light intensity of a lighting device. CONSTITUTION:An interference film filter 3 which passes vertical light as it is, but reflects light having an angle larger than a certain incidence angle to the side of the lighting device 2 is provided on the top surface of the lighting device 2 provided behind the liquid crystal display element 4. Consequently, the interference film filter 3 emits only the light in vertical direction and other light is repeatedly reflected by the interference filter 3 and in the lighting device 2, so that only the light in vertical direction is emitted toward the liquid crystal display element 4. Then the light output in the vertical direction (viewing direction of user) of the interference film filter 3 is increased.

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 for displaying a display content of a liquid crystal display element to a user by light emitted from a lighting device.

[0002]

2. Description of the Related Art As prior art, Japanese Patent Laid-Open No. 62-1827
The technique disclosed in Japanese Patent No. 87 is known. In this technique, a light-shielding member made of a material that reflects light, such as aluminum foil, and capable of arbitrarily controlling the amount of light transmission is provided between the liquid crystal display element and the illumination.

[0003]

The provision of the light shielding member reduces the transmittance of light passing through the liquid crystal display element, so that the brightness of the liquid crystal display device as a whole is reduced. In the conventional liquid crystal display device, light transmitted through the liquid crystal display element is diffused as shown by a chain line B in FIG. On the other hand, in some cases, such as a display device for a vehicle, the visual recognition position of the user is limited to a specific narrow range. Thus, in the case where the user's visual recognition position is limited to a specific narrow range, the diffused light is wasted, and it is necessary to further increase the luminous intensity of the lighting device in order to increase the brightness in the specific direction. there were.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a liquid crystal display device capable of increasing the brightness in the viewing direction of a user without increasing the luminous intensity of the lighting device.

[0005]

A liquid crystal display device according to the present invention comprises a liquid crystal display element for displaying to a user using liquid crystal,
An illumination device that irradiates the liquid crystal display element with light, and an interference film filter that is arranged between the liquid crystal display element and the illumination device and converges the light emitted by the illumination device toward a user's visual recognition position. The technical means including and was adopted.

[0006]

In the liquid crystal display device having the above structure, the light emitted from the illumination device is converged by the interference film filter,
It is aimed at the user's visual recognition position. As a result, the light transmitted through the liquid crystal display element is radiated toward the visual recognition position of the user.

[0007]

According to the liquid crystal display device of the present invention, as described above, the light emitted from the illumination device is converged toward the user by the interference film filter. Is directed to the user's visual recognition position without waste. For this reason, the brightness of the liquid crystal display device at the position visually recognized by the user becomes higher than the conventional one without increasing the luminous intensity of the lighting device.

[0008]

EXAMPLE Next, a liquid crystal display device of the present invention will be described based on an example shown in the drawings. [Structure of Embodiment] FIGS. 1 to 4 show an embodiment of the present invention, and FIG. 1 is a schematic sectional view of a liquid crystal display device. The liquid crystal display device 1 of the present embodiment is mounted on an automobile and is composed of a lighting device 2, an interference film filter 3, and a liquid crystal display element 4.

The illuminating device 2 includes an irradiating section 5 for irradiating light,
The diffusion unit 6 uniformly diffuses the light emitted from the irradiation unit 5. The irradiation unit 5 includes a halogen lamp 7 that emits strong light and a diffusion unit 6 that diffuses the light emitted by the halogen lamp 7.
It consists of a reflector 8 pointing toward. The diffusing section 6 is a glass on which an acrylic diffusing plate 9 for diffusing the light received from the irradiating section 5 and a light-shielding film 10 for eliminating the uneven brightness distribution of the light transmitted through the diffusing plate 9 shown in FIG. It is composed of the plate 11, and the distance between the diffusion plate 9 and the glass plate 11 is set to be as small as about 1 cm. The light-shielding film 10 is made of, for example, aluminum that reflects light, and its distribution on the glass plate 11 is determined by simulation so that the light transmittance is reduced in a strong light portion that has passed through the diffusion plate 9.

The interference film filter 3 is an optical filter that sharpens the directivity of the light by directing the traveling direction of the transmitted light in one direction and directs the light emitted from the illumination device 2 to the visual recognition position of the user. , An example is Ti2O2-Si
It consists of a multilayer film of O2. The characteristic of the interference film filter 3 is that light in the vertical direction is allowed to pass through the interference film filter 3 as it is, but light having an angle larger than a certain incident angle is reflected to the incident side (see FIG. 3). The light reflected by the illuminating device 2 is reflected by the reflector 8 and the diffusing plate 9 and again enters the interference film filter 3, and part of the light passes through the interference film filter 3 as light in the vertical direction and the rest of the light. Are again reflected to the lighting device 2 side. By repeating this, the light output of the component perpendicular to the interference film filter 3 increases, and the light distribution is as shown by the solid line A in FIG. By adjusting the vertical direction of the interference film filter 3 to the visual recognition position of the user, the light incident from the illumination device 2 is converged and emitted in a specific range (a specific range centered on the visual recognition position of the user). be able to.

The liquid crystal display element 4 has a well-known structure in which liquid crystal is sandwiched between two transparent plates, a transparent electrode is provided on the transparent plate, and the transparent electrodes are energized and controlled. A monochrome or color liquid crystal display element is used. ing.

[Operation of Embodiment] Next, the operation of the above embodiment will be briefly described. Halogen lamp 7 of lighting device 2 is ON
When liquid crystal display is performed on the liquid crystal display element 4,
The light emitted from the halogen lamp 7 is diffused by the diffusion plate 9. The diffused light is repeatedly reflected and diffused by the light-shielding film 10 in which the vapor deposition area, the vapor deposition site, and the reflectance are set according to the nonuniformity of the light emitted from the diffuser plate 9, and the diffused light is emitted from the glass plate 11. The plane uniform light is emitted to the interference film filter 3. The light that has entered the interference film filter 3 is converged and emitted in a specific range centered on the visual recognition position of the user due to the characteristics of the interference film filter 3. Then, the light emitted from the interference film filter 3 to the liquid crystal display element 4 passes through the liquid crystal display element 4 in accordance with the display state of the liquid crystal and is emitted toward the position visually recognized by the user.

[Effects of the Embodiment] In this embodiment, the lighting device 2 is provided between the halogen lamp 7 and the plane for emitting light.
Since the light emitted from the lighting device 2 is made uniform in the plane by providing the light shielding film 10, the lighting device 2 is compared with the technique of separating the two diffusion plates to eliminate the uneven brightness (see FIG. 5). Can be thinned by several cm. Therefore, the liquid crystal display device 1 of the present embodiment is suitable for use as a display means that requires a narrow space, such as an automobile. Further, in the liquid crystal display device 1 of the present embodiment, the light emitted from the illumination device 2 is converged toward the user by the interference film filter 3, so that the light transmitted through the liquid crystal display element 4 is not wasted by the user. Faced to the viewing position. Therefore, the lighting device 2
The decrease in brightness due to the provision of the light shielding film 10 inside can be recovered by the interference film filter 3.

[Modification] In the above embodiment, an example in which the illumination device is provided with a light-shielding film to eliminate the uneven brightness is shown. However, as shown in FIG. You can eliminate the unevenness. Further, the present invention may be applied to a liquid crystal display device using an illuminating device that has not been subjected to processing for eliminating uneven brightness. Further, although an example in which a halogen lamp is used is shown as an example of the illumination device, another point light source such as an incandescent lamp is used, or as shown in FIG. 6, a linear light source 13 using a fluorescent lamp, a neon tube, or the like is used. May be.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a liquid crystal display device (Example).

FIG. 2 is a perspective view of a glass plate on which a light-shielding film is deposited (Example).

FIG. 3 is a graph showing the relationship between the incident angle and the transmittance of the interference film filter (Example).

FIG. 4 is a light distribution distribution of light that has passed through an interference film filter (Example).

FIG. 5 is a schematic sectional view of a liquid crystal display device (modification).

FIG. 6 is a schematic sectional view of a liquid crystal display device (another modification).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Illumination device 3 Interference film filter 4 Liquid crystal display element

Claims (1)

[Claims] 1. A liquid crystal display element for displaying to a user using liquid crystal, an illuminating device for irradiating the liquid crystal display element with light, and a illuminating device arranged between the liquid crystal display element and the illuminating device. A liquid crystal display device comprising: an interference film filter that converges light emitted from the device toward a user's visual recognition position.