Computer graphics processing and selective visual display system – Plural physical display element control system – Display elements arranged in matrix
Reexamination Certificate
1998-02-17
2003-04-29
Wu, Xiao (Department: 2774)
Computer graphics processing and selective visual display system
Plural physical display element control system
Display elements arranged in matrix
C345S102000, C396S296000
Reexamination Certificate
active
06556179
ABSTRACT:
This application claims the benefit of Japanese Application, Nos. 9-048458 and 9-169669 which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a display device and more specifically to a display device which is installed on or near a specular surface of an optical finder of a silver salt camera or the like, superimposes a pattern on a finder image and displays the pattern. The present invention also relates to a camera having this display device.
2. Description of the Prior Art
A display device for performing a predetermined display in a finder of a camera or the like has heretofore adopted a method in which a liquid crystal panel filled with a twist type liquid crystal material is controlled by a transparent electrode (ITO). The method using a polymer dispersed liquid crystal has also adopted the method in which this liquid crystal is filled over a glass material surface, a control is operated by the transparent electrode and the display is performed. Recently, the method in which information is displayed in the finder of the camera by the use of a host/guest type liquid crystal has been also adopted.
In case of the camera, many fine prisms are aligned on a finder surface so that they may be shaped into characters and symbols to be displayed. A light is emitted from an upper or a lower portion of the finder, whereby a reflected light directly comes into eyes through the finder so that the characters and symbols are displayed.
Any of the above-described methods has both merits and demerits. Any methods are not said to be desirable. The display device using the twist type liquid crystal has a visual field angle. The display is limited depending on a direction of observation. Furthermore, since a rotating angle of the liquid crystal is controlled, conditions are disadvantageously varied due to a temperature or the like. Thus, a contrast control is required. This results in inconvenience. In case of another arrangement, that is, when the twist type liquid crystal is used for the finder of the camera so that a transmission-type superimposition is performed, a polarizing plate is required for a liquid crystal display. Thus, since a light transmittance is 50% at maximum in a portion which transmits the light, a visual field of the finder is considerably darkened. Therefore, a subject image to be picked up in the finder cannot be clearly seen.
Furthermore, in the method using the polymer dispersed liquid crystal as it is, when the polymer dispersed liquid crystal is turned off, it is cloudy opaque or white turbid and the light is thus scattered. When the polymer dispersed liquid crystal is turned on, it is transparent. Due to such properties, a logic circuit for turning off a portion to be displayed must be constructed. This causes a problem. The fact that a display portion is displayed in a turn-off state does not mean that a display logic has only to be reversely operated. Thus, the problem is not solved.
In case of the commercially available/typical liquid crystal controlled by front and rear electrodes, only when both the front and rear electrodes are turned on, the display portion is visibly recognized. Both the electrodes are therefore arranged so that routes of the front and rear electrodes guided to the display portion may not overlap with each other. Both the electrodes are turned on, whereby it is possible to visibly recognize the display portion alone where the electrodes overlap with each other. This means that the portion alone, where a logical product of the front and rear electrodes is obtained, is displayed in accordance with the logic indicating that the display is accomplished by a turn-on.
However, if this display logic is reversely operated, when at least one of the front and rear electrodes is turned off, the display is performed. Thus, a desired portion alone cannot be displayed by controlling the two electrodes. In this case, the display portion is displayed by a logical sum of both the electrodes. In this method, the selective and limited display cannot be therefore performed. Since the routes of the electrodes are displayed, it is difficult to obtain the high-quality display device.
The method reflecting the light by a microprism is different from the method in which the display portion is blackly emerged by shutting out the light from the portion to be displayed. That is, since the display portion apparently emits the light, the display portion has excellent visibility. Advantageously, the display can be clearly seen even if a background is dark. However, even when the display portion is not displayed, the display portion does not transmit the light and the light remains shut out from the display portion. Thus, this portion disadvantageously conceals the background. Also required is a three-dimensional arrangement in which a projecting portion is located over or under a display surface. Therefore, disadvantageously, an installation is considerably limited for loading this arrangement. It is thus necessary to manufacture a change in the display contents to correct or reform an expensive plastic injection mold. This causes not only a cost problem but also a problem of waste of time. This is a factor which prevents the display contents from being optionally changed as required.
Furthermore, heretofore, in the camera having an AF (auto-focus control) mechanism, an AF auxiliary light irradiating device for irradiating the subject with an AF auxiliary light has been exclusively disposed on a camera body. At the time of the dark background or the like, the subject is irradiated with a luminous flux from a light source such as an LED of this device. The reflected light is detected, whereby an auto-focus control is performed. This device is individually disposed in the camera in order to use the AF auxiliary light.
A single-lens reflex camera is provided with a mechanism in which a diaphragm value shown on a lens ring of a lens attached to the camera is projected into the finder visual field in order that the diaphragm value is confirmed in the finder at the time of a pick-up. This mechanism includes a lens ring illuminating device having an illumination optical system for partially illuminating the lens ring in order to effectively perform such a projection even in a dark environment. This illumination optical system directly illuminates a mark indicative of the diaphragm value of a diaphragm member, whereby the mark of the diaphragm value can be readably projected into the finder even when a natural light is weak.
However, if an additional optical system or the like is arranged in the camera in order to project the AF auxiliary light as described above, this is a considerable burden on the camera having a limited space. Furthermore, since an additional member is needed, a cost is increased. Thus, this device is not desirable in view of the cost. This problem is similarly caused in case of the device for illuminating the diaphragm member.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a display device having excellent visibility and no dependence on a visual field angle and capable of accomplishing a high-quality display and of immediately switching both of a display brightly emerged in a background and a dark display in accordance with a subject condition and a user's request.
In order to solve the above problem, a display device of the present invention comprises: a pair of plate-like light transmittable members; a display member located so as to form a predetermined pattern between a pair of light transmittable members, the display member being composed of a material whose light transmittance is electrically changed; and a pair of light transmittable electrodes, at least one of a pair of light transmittable electrodes having a shape corresponding to the pattern, a pair of light transmittable electrodes being formed on a pair of light transmittable members and for electrically controlling the material.
According to this display device, the material locat
Homma Itaru
Iwane Toru
Ueda Takehiko
Watanabe Toshimi
Morgan & Lewis & Bockius, LLP
Nikon Corporation
Wu Xiao
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