Display apparatus capable of controlling range of visually recognizable observation angle

Abstract

A display apparatus includes a display panel that displays an image, and a viewing angle restricting element that selectively irradiates light with directivity in a restricting direction at a predetermined angle with respect to a direction of normal to the display panel, toward an observation side of the display panel.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a perspective view of a display apparatus according to an embodiment of the present invention;

FIG. 2A shows exit light from the display apparatus when wide viewing angle display is selected;

FIG. 2B shows exit light from the display apparatus when narrow viewing angle display is selected;

FIG. 3 is an enlarged side view of part of a surface illuminant in the display apparatus;

FIG. 4 is a graph showing the intensity distribution of illumination light from the surface illuminant;

FIG. 5A is an enlarged side view of part of a viewing angle restricting element in the display apparatus;

FIG. 5B is an enlarged front view of part of the viewing angle restricting element in the display apparatus; and

FIG. 6 is a graph showing the intensity distribution of restricting light from the viewing angle restricting element.

Claims

1. A display apparatus comprising: a display panel that displays an image; anda viewing angle restricting element that selectively irradiates light with directivity in a restricting direction at a predetermined angle with respect to a direction of normal to the display panel, toward an observation side of the display panel.

2. An apparatus according to claim 1, wherein the viewing angle restricting element is arranged on the observation side of the display panel, and formed of a member that transmits image light irradiated from the display panel.

3. An apparatus according to claim 1, wherein the viewing angle restricting element comprises a light irradiating device that irradiates restricting light including light intensity peaks in at least two directions inclined in one direction and a direction opposite thereto at predetermined angles with respect to a direction of normal to the display panel, toward the observation side.

4. An apparatus according to claim 3, wherein the light irradiating device irradiates light with directivity including light intensity peaks in directions inclined toward one side in a horizontal direction seen from the observation side of the display apparatus and toward the other side opposite thereto at predetermined angles with respect to the direction of normal to the display apparatus.

5. An apparatus according to claim 1, wherein the display panel includes a range of viewing angle where a display image is visually recognizable, within an angular range that includes an exit direction of the light with directivity irradiated from the viewing angle restricting element and is wider than a range of spread angle of the light irradiated from the viewing angle restricting element.

6. An apparatus according to claim 1, wherein the display panel includes a predetermined range of viewing angle where a display image is visually recognizable, and the viewing angle restricting element irradiates light within a restricting angular range in the range of viewing angle that includes the predetermined restricting direction and is narrower than the range of viewing angle.

7. An apparatus according to claim 1, further comprising a surface illuminant that is arranged on a side opposite to the observation side of the display panel and irradiates the display panel with illumination light.

8. An apparatus according to claim 7, wherein the surface illuminant irradiates the display panel with the illumination light that spreads in a predetermined angular range including a direction of the light with directivity irradiated from the viewing angle restricting element, the direction being inclined with respect to the direction of normal to the display panel.

9. An apparatus according to claim 7, wherein the surface illuminant comprises a light guide plate that is formed of a flat plate-like transparent member, guides light entering thereto through at least one end face thereof, and irradiates the light through one plate surface thereof, andat least one light-emitting element that is arranged to oppose said at least one end face and cases light to enter the light guide plate through the end face.

10. An apparatus according to claim 1, wherein the viewing angle restricting element comprises a light guide member that is formed of a plate-like transparent member including two opposing plate surfaces and end faces intersecting the plate surfaces, and irradiates light entering the transparent member through at least one end face thereof, from one of the two plate surfaces of the transparent member in two directions inclined toward one side and a side opposite thereto at predetermined angles with respect to a normal to the plate surface, anda light source unit that is arranged on the end face of the light guide member and causes light to enter the light guide member through the end face thereof.

11. An apparatus according to claim 1, wherein the viewing angle restricting element comprises a light guide member that is formed of a transparent plate including two opposing plate surfaces, two end faces intersecting the two plate surfaces, and two other opposing side end faces respectively intersecting the two plate surfaces and the two end faces, and includes an incident end face, on at least one of the two end faces, to receive light, an exit surface, on one of the two plate surfaces, to irradiate light, and a reflection surface, on the other plate surface, to internally reflect light entering through the incident end face in directions inclined toward one side end face and the other side end face with respect to a normal to the incident end face, toward the exit surface in directions inclined in one direction and the other direction with respect to a plane including the normal to the incident end face and a normal to the exit surface, the reflection surface opposing a surface of the display panel on the observation side; anda light source unit that is arranged to oppose the incident end face of the light guide member and irradiates light in directions inclined toward one side end face and the other side end face of the light guide member with respect to the normal to the incident end face of the light guide member, toward the incident end face of the light guide surface.

12. An apparatus according to claim 11, wherein the light source unit comprises a light-emitting member that is arranged to oppose the incident end face of the light guide member and emits light toward the incident end face of the light guide member, anda prism array that is arranged between the incident end face of the light guide member and the light-emitting member, and refracts the light from the light-emitting member in directions inclined toward one side end face and the other side end face of the light guide member with respect to the normal to the incident end face of the light guide member, to enter the light guide member through the incident end face.

13. An apparatus according to claim 1, wherein the display panel comprises a liquid crystal display panel including a screen region where pixels that control transmission of light are arranged in a matrix, and a surface illuminant that is arranged on a side opposite to the observation side of the liquid crystal display panel and radiates illumination light spreading in an angular range that includes an exit direction of the light with directivity irradiated from the viewing angle restricting element and is wider than a range of spread angle of the light irradiated from the viewing angle restricting element, toward the liquid crystal display panel.

14. A display apparatus comprising: a display panel that displays an image within a predetermined range of viewing angle where an image is visually recognizable; anda viewing angle restricting element that is arranged on an observation side of the display panel, transmits image light irradiated from the display panel, and selectively irradiates, toward the observation side, restricting light with directivity having a light intensity peak in a restricting direction that is within the range of viewing angle and inclined at a predetermined angle with respect to a direction of normal to the display panel.

15. An apparatus according to claim 14, further comprising a surface illuminant that is arranged on a side opposite to the observation side of the display panel and irradiates the display panel with illumination light that spreads in a range of viewing angle where the image is visually recognizable.

16. An apparatus according to claim 14, wherein the viewing angle restricting element irradiates the restricting light in a restricting angular range that includes a restricting direction inclined at a predetermined angle with respect to the direction of normal to the display panel and is narrower than the range of viewing angle.

17. An apparatus according to claim 14, wherein the viewing angle restricting element comprises a light guide member that is formed of a plate-like transparent member including two opposing plate surfaces and end faces intersecting the plate surfaces, and irradiates light entering the transparent member through at least one end face thereof, from one of the two plate surfaces of the transparent member in two directions inclined toward one side and a side opposite thereto at predetermined angles with respect to a normal to the plate surface, anda light source unit that is arranged on the end face of the light guide member and causes light to enter the light guide member through the end face thereof.

18. An apparatus according to claim 17, wherein the light source unit comprises a light-emitting element array that is arranged to oppose the incident end face of the light guide member and includes light-emitting elements arrayed that emit light toward the incident end face of the light guide member, anda prism array that includes isosceles triangular prism portions arrayed, is arranged between the incident end face of the light guide member and the light-emitting element array, and refracts the light from the light-emitting element array in directions inclined toward one side end face and the other side end face of the light guide member with respect to the normal to the incident end face of the light guide member, to enter the light guide member through the incident end face.

19. A display apparatus comprising: a liquid crystal display panel that includes a screen region where pixels that control transmission of light are arranged in a matrix, and displays an image formed of the pixels within a visually recognizable predetermined range of viewing angle;a viewing angle restricting element that comprises a light guide member and a light source unit, the light guide member being arranged on an observation side of the liquid crystal display panel, formed of a plate-like transparent member including two opposing plate surfaces and end faces intersecting the plate surfaces, transmitting image light irradiated from the display panel, and irradiating light entering the transparent member through at least one end face thereof, through one of the two plate surfaces of the transparent member in two directions inclined toward one side and a side opposite thereto at predetermined angles with respect to a direction of normal to the plate surface within the range of viewing angle, and the light source unit being arranged at the end face of the light guide member and causing the light to enter the light guide member through the end face; anda surface illuminant that is arranged on a side opposite to the observation side of the liquid crystal display panel and irradiates the liquid crystal display panel with illumination light that spreads within the range of viewing angle.

20. An apparatus according to claim 19, wherein the viewing angle restricting element comprises a light guide member that is formed of a transparent plate including two opposing plate surfaces, two end faces intersecting the two plate surfaces, and two other opposing side end faces intersecting the two plate surfaces and the two end faces, and includes an incident end face, on at least one of the two end faces, to receive light, an exit surface, on one of the two plate surfaces, to irradiate light, and a reflection surface, on the other plate surface that includes inclined reflecting portions to internally reflect light entering through the incident end face in directions inclined toward one side end face and the other side end face with respect to a normal to the incident end face, toward the exit surface in directions inclined in one direction and the other direction with respect to a plane including the normal to the incident end face and a normal to the exit surface, the reflection surface opposing a surface of the display panel on the observation side; anda light source unit that is arranged to oppose the incident end face of the light guide member and irradiates light in directions inclined toward one side end face and the other side end face of the light guide member with respect to the normal to the incident end face of the light guide member, toward the incident end face of the light guide surface to reach the reflecting portions of the light guide member.