Liquid crystal viewfinder

• US 4,977,456 A
• Filed: 02/13/1990
• Issued: 12/11/1990
• Est. Priority Date: 06/04/1985
• Status: Expired due to Term

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Furuya, Yoshikiyo
• Primary Examiner(s): Chin, Tommy P.
• Application Number:
  US07/479,192
• Time in Patent Office: 301 Days
• Field of Search: 358/224, 358/213.11, 358/213.13, 358/236, 358/241, 358/209, 358/59, 358/60
• US Class Current: 348/333.01
• CPC Class Codes: G02F 1/1313 specially adapted for a particular application
• CPC Class Codes: H04N 23/53 of electronic viewfinders, e.g. rotatable or detachable
• CPC Class Codes: H04N 23/63 by using electronic viewfinders

Abstract

An electronic viewfinder for displaying video images captured in an attached electronic camera utilizes a liquid crystal display which can be illuminated from the rear by ambient illumination or by light from an included fluorescent lamp. The liquid crystal display is positioned at a slight angle to the viewer'"'"'s line of sight and light transmitted by the display is diffused thereafter to provide a high quality image.

Claims

1. An electronic viewfinder for reproducing an image representative of video signals captured by a video camera used by a viewer, the viewfinder comprising:

a liquid crystal assembly which includes liquid crystal display panel means responsive to said video signals for reproducing the image, said liquid crystal display panel means having a front surface and a rear surface;

housing means for enclosing the liquid crystal display panel means;

artificial illuminating means located within the housing means and directly behind the rear surface of the liquid crystal display panel means, relative to the viewer, for illuminating the liquid crystal display panel means;

first diffusing means located between the liquid crystal display panel means and artificial illuminating means for controlling the illumination provided by the illuminating means so as to uniformly irradiate the surface of the liquid crystal display panel means facing the illuminating means;

circuit means coupled to the video camera and the liquid crystal display panel means and including a main electric circuit assembly, said circuit means for supplying the video signals to the liquid crystal panel display means;

first detachable connector means for detachably coupling the liquid crystal assembly to the main electric circuit assembly; and

second detachable connector means for detachably coupling said artificial illuminating means to said main electric circuit assembly.

2. The electronic viewfinder of claim 1, and further comprising:

second diffusing means in the line of sight between the viewfinder and the liquid crystal display panel means onto which said image is projected for viewing when the liquid crystal display panel means is actuated by the video signals, the second diffusing means being located in close proximity to the liquid crystal display panel means to avoid fading-off of the image.

3. The electronic viewfinder of claim 2 wherein the second diffusing means comprises one of a diffusing surface on a transparent plate which is adjacent to the liquid crystal display panel means and a diffusing surface on the face of the liquid crystal display panel means.

4. The electronic viewfinder of claim 2 wherein the second diffusing means comprises one of a ground glass surface, a surface having a multiplicity of convex lenses formed thereon, and a surface having thereon lens-like materials of a different refractive index.

5. The electronic viewfinder of claim 2 wherein the liquid crystal display panel means comprises a plurality of image forming elements which are spaced apart at a uniform pitch, and the second diffusing means comprises lens-like elements which are spaced apart at the same pitch.

6. The electronic viewfinder of claim 1 wherein the artificial illuminating means includes a fluorescent lamp.

7. The electronic viewfinder of claim 6, and further comprising:

reflecting means adjacent to the fluorescent lamp for redirection light therefrom onto the liquid crystal display panel means.

8. The electronic viewfinder of claim 7, further including removable lamp cover means detachably connected to and for removably positioning the fluorescent lamp and the reflecting means to illuminate the rear surface of the liquid crystal panel display means.

9. The electronic viewfinder of claim 6, and further comprising:

light guiding means for directing light from the fluorescent lamp onto the rear of the liquid crystal display panel means.

10. The electronic viewfinder of claim 9 wherein the fluorescent lamp is located obliquely to the rear of the liquid crystal display panel means and the light guiding means comprises a transparent body having a convex surface which faces the rear surface of the liquid crystal display panel means for directing light thereto and having a concave surface which is located obliquely relative to the convex surface for collecting light from the fluorescent lamp.

11. The liquid crystal display means of claim 10 and further comprising:

aperture means in a wall of the housing for admitting ambient light thereto; and

reflector means disposed in the housing between the fluorescent lamp and the liquid crystal display panel means for directing light from the aperture means to the liquid crystal display panel means.

12. The electronic viewfinder of claim 11 wherein the reflector means is semitransparent.

13. The electronic viewfinder of claim 11 wherein the aperture means comprises a diffusing surface.

14. The electronic viewfinder of claim 9, further including removable lamp cover means detachably connected to the housing means and for removably locating the fluorescent lamp and the light guiding means to illuminate the rear surface of the liquid crystal panel display means.

15. The electronic viewfinder of claim 6, and further comprising:

means adjacent the liquid crystal display panel means for directing ambient light thereto in lieu of light from the fluorescent lamp.

16. The liquid crystal display of claim 6 and further comprising:

removable lamp cover means in a wall of the housing means on which the fluorescent lamp is carried for locating the fluorescent lamp at the rear of the liquid crystal display panel means.

17. The electronic viewfinder of claim 1 wherein the artificial illuminating means includes reflector means and further comprising:

housing means for enclosing the liquid crystal display panel means and the reflector means; and

aperture means in a wall of the housing means through which ambient light can be directed to the reflector means.

18. The electronic viewfinder of claim 17 wherein the reflector means is semitransparent.

19. The electronic viewfinder of claim 17 wherein the aperture means comprises a diffusing surface.

20. The electronic viewfinder of claim 1, further including semi-transparent reflector means between the liquid crystal display panel means and the artificial illuminating means;

and window means in the housing means for receiving light from outside of the housing to illuminate the liquid crystal display panel means, whereby use of power to energize the source of artificial light is minimized.

21. The electronic viewfinder of claim 1, further including removable cover means for removably positioning the artificial illuminating means adjacent to the rear surface of the liquid crystal display panel means.

22. The electronic viewfinder of claim 1, further including masking plate means disposed adjacent to and facing the front surface of the liquid crystal display panel means and for preventing leakage of light from the artificial illuminating means.

23. The electronic viewfinder of claim 22, wherein a cover glass serves as the masking plate means.

24. The electronic viewfinder of claim 1, wherein the artificial illuminating means is disposed substantially perpendicularly to the rear surface of the liquid crystal display panel means.

25. The electronic viewfinder of claim 1, further including removable cover means for removably positioning the artificial illuminating means adjacent to the rear surface of the liquid crystal display panel means.

26. The electronic viewfinder of claim 1, further including masking plate means disposed adjacent to and facing the front surface of the liquid crystal display panel means and for preventing leakage of light from the artificial illuminating means.

27. The electronic viewfinder of claim 1, further including reflecting means for reflecting light from said artificial illuminating means onto the liquid crystal display panel means and located behind said artificial illuminating means relative to the viewer.