JPH1138496A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel display device resolved in each defect in conventional light shielding and illuminating types. SOLUTION: The display device is provided with a plate 13 having a notch 14 formed inside, on which a luminous flux as a background image is made incident from one surface and which corresponds to a luminous flux such as a graphic, a character and a mark which is superimposed on the background image and outgoing from the other surface and a liquid crystal seal member 15 which is provided inside the notch 14 and can change a refractive index. The refractive index of the liquid crystal seal member 15 is adjusted to be greater than that of the plate 13. Illuminating light made incident from the side of the plate 13 is reflected by the boundary of the liquid crystal seal member 15 and the plate 13 and a luminous flux LR for displaying a focus detecting region display mark is superimposed on the background image OL and outgoing from the other surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device for displaying various marks together with a background image in a field of view of a camera or an image input device.

[0002]

2. Description of the Related Art Conventionally, as a display device for displaying a frame indicating a focus detection area on a finder device of a camera, a light-shielding display device using a liquid crystal element or an electrochromic element has been known. The light-blocking display device has a display element such as a liquid crystal element disposed in a field of view of a finder screen, and a part of the field of view is shielded in a frame shape by the display element to superimpose on a background image as a focus detection area. Things. In addition, a mark for displaying the focus detection area is formed on a microprism arranged at a position conjugate to the background image, and the microprism is illuminated obliquely from above or below the finder, and the microprism is illuminated. There is also known an illuminated display device that brightly displays a frame of a focus detection area on a background image of the above.

[0003]

However, in the light-shielded display device, the light-shielded frame only overlaps with the background image.
The visibility is low for the photographer, and when the background is dark, almost no visibility can be obtained. In addition, although the illuminated display device has high visibility, it requires a prism and an optical system for irradiating illumination light in the finder, and the finder device cannot be assembled by itself, has a complicated structure, is difficult to adjust,
There is a problem that a large space is required. In addition, when the illumination type display device is arranged two-dimensionally, for example, when the focus detection regions are arranged in a cross shape, it is difficult to secure the light guide path of the illumination light to the intersecting regions.

[0004] It is an object of the present invention to provide a new display device which solves the drawbacks of the conventional light-shielding type and illumination type.

[0005]

The present invention will be described with reference to FIG. 1 showing an embodiment. (1) The invention according to claim 1 is applied to a display device in which information images such as figures, characters, and symbols are superimposed on a background image incident from one surface to output information images such as graphics, characters, and symbols from the other surface. A flat plate 13 having a space 14 corresponding to the information image formed therein, and a refractive index variable member 15 provided inside the space 14 and capable of changing a refractive index, and illumination light incident from the side of the flat plate 13 Is incident on the variable-refractive-index member 15 having a larger refractive index than the refractive index of the flat plate 13, and the incident light is reflected at the interface between the variable-refractive-index member 15 and the flat plate 13 to form figures, characters, symbols, and the like. The light beam LR is superimposed on the background image OL. (2) In the display device according to the first aspect of the present invention, the refractive index of the refractive index variable member 15 is set between the first refractive index and the second refractive index.
(> The first refractive index), and the refractive index of the flat plate 13 is made smaller than at least the second refractive index. When the refractive index variable member 15 has the first refractive index, the light incident from the side goes straight without being reflected at the interface, and only the light flux of the background image is emitted from the display device.
When the refractive index variable member 15 is adjusted to the second refractive index, light incident from the side is reflected at the interface, and the information image is superimposed on the background image. (3) According to a third aspect of the present invention, in the display device of the second aspect, the refractive index of the flat plate 13 is substantially equal to the first refractive index. (4) In the display device according to the second aspect of the present invention, the refractive index of the flat plate 13 is made smaller than the first refractive index, and a part of the incident light from the side is constantly reflected so that the background can be obtained. Superimposed on the statue. The embodiment will be described with reference to FIGS. (5) According to a fifth aspect of the present invention, in the display device according to any one of the first to fourth aspects, the incident light is sequentially reflected such that the reflected light from the interface is emitted almost perpendicularly from the other surface. The first and second reflection surfaces 14a and 14b are provided at the interface. If the second refractive index of the variable refractive index member 15 cannot be made much larger than the refractive index of the flat plate 13, the angle of total reflection of the light incident from the side at the interface becomes larger than 45 degrees, and one reflection occurs. In this case, the reflected light from the interface cannot coincide with the emission direction of the background image. Therefore, the reflected light of the information image is made substantially coincident with the emission direction of the background image by sequentially reflecting at least the incident light on the first and second reflecting surfaces 14a and 14b.

The present invention has been described in relation to the drawings of the embodiments in the section of means for solving the above problems, but the present invention is not limited to the embodiments.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The display principle of a display device according to the present invention will be described with reference to FIGS. When a rectangular mark 12 is displayed at a central portion of a field of view 11 with uniform brightness as shown in FIG. 1, a rectangular mark 1 on a transparent flat plate 13 is displayed as shown in FIG.
A cut 14 is formed at the position 2 and a variable refractive index member 15 is provided on the surface of the transparent flat plate 13. The cut 14 is formed by providing an opening of the width and the length of the rectangular mark 12 to be displayed on the surface of the transparent flat plate 13, and one of the cuts 14 is formed with an inclined surface 14 </ b> M.

The refractive index variable member 15 is formed of a material whose refractive index increases when a predetermined electric field is applied in the front and back directions, and whose refractive index when no electric field is applied is substantially equal to the refractive index of the transparent plate 13 for display. You. A light source 16 is provided to face the end face of the transparent plate 13 for display, and the illumination light LL of the light source 16 is cut into the transparent plate 13 for display from the end face (side).
Is incident toward.

When a predetermined electric field is not applied to the variable refractive index member 15, the display transparent flat plate 13 and the refractive index variable member 15 have substantially the same refractive index.
The illumination light LL incident from the end face of No. 3 goes straight without being reflected at the cut 14 and is attenuated by repeating reflection and scattering on the inner surface of the transparent plate 13 for display. At this time, as shown in FIG. 2, the light flux OL of the background image is transmitted from the transparent plate 13 for display to the refractive index variable member 15.
, And only the background image is displayed in the field of view.

When a predetermined electric field is applied to the refractive index variable member 15, the refractive index increases, and the illumination light LL incident on the display transparent flat plate 13 is totally reflected by the cut 14 as shown in FIG. The light beam LR of the superimposed image (information image) is emitted from the surface of the member 15. Accordingly, the light flux OL of the background image overlaps, and the background image and the rectangular display mark 12 are displayed in the viewfinder in an overlapping manner.

The above is the display principle of the display device according to the present invention. Here, a more specific display device will be described.

The display transparent plate 13 has a refractive index of 1.53,
Assuming that the refractive index of the variable refractive index member 15 is 1.53 to 1.8, the critical angle of total reflection at the cut 14 when the refractive index variable member 15 is set to the maximum refractive index is 58.2 degrees. Since the illumination light LL is made to enter from the side in a direction perpendicular to the thickness direction of the transparent plate 13 for display, the angle of the cut 14 with respect to the horizontal plane is set to 31.8 degrees or less as shown in FIG. Then, the incident light is totally reflected at the cut 14.

As can be seen from FIG. 3, the light LR totally reflected at the cut 14 does not travel vertically from the exit surface 13a of the transparent plate 13 for display, but travels at a certain angle (58.2 degrees). In order to superimpose and display the reflected light LR from the cut 14 with the background image, it is necessary to emit the reflected light vertically from the exit surface of the variable refractive index 15.

Therefore, as shown in FIGS. 4 and 5, the reflecting surface of the cut 14 is formed by a first reflecting surface 14a and a second reflecting surface 14a.
b, and the first reflection surface 14a is
Is set to 22 degrees with respect to the incident surface, and the second reflection surface 14b is set to 67 degrees. Thereby, the light LR reflected at the cut 14
Will be reflected almost perpendicularly to the exit surface of the refractive index variable member 15. In FIG. 4, the transparent electrodes 17a and 17b are provided only in a region corresponding to the cut 14.

FIGS. 6 to 8 are views for explaining an embodiment in which the display device according to the present invention is applied to a finder display device. In FIG. 6, the light flux of the subject image that has passed through the lens LE is reflected upward by the quick return mirror MR and forms an image on the finder screen FS. The display device DU installed on the finder screen FS is
It is composed of a transparent flat plate 23, a liquid crystal sealing member 25, and a light source 26. The display device DU displays focus detection display areas L, R, U, C, and D in the field of view, as shown in FIG. In this case, a light source 26 incorporating three LEDs 26a, 26b, 26c is provided on the end surface of the transparent plate 23 for display, the cutout (not shown) of the display region U is illuminated by the LED 26a, and the regions L, C, R are illuminated by the LED 26b. Illuminate the cuts 24L, 24C, 24R (see FIG. 8),
The notch 24D of the area D is displayed by the LED 26c. LE
D26b illuminates the three cuts 24L, 24C, and 24R. As shown in FIG.
Since the liquid crystal sealing member 25 functions as an optical waveguide, the cuts 24C and 24L in the regions C and L can be illuminated with a sufficient amount of light.

When the display of the areas C and L is dark due to insufficient light quantity, as shown in FIG.
Steps are provided in R, 24C, and 24L, and the illumination light of the LED 26b is made into parallel light by the lens 27, and the transparent plate 23 for display is used.
May be incident.

In the case of the finder display device shown in FIGS. 6 to 8, the transparent electrodes are provided only in the notches for displaying the respective regions L, R, U, C and D, as in FIG. The notches are provided with first and second reflecting surfaces in the same manner as in FIG. 4 so that the reflected light for display is emitted perpendicularly from the exit surface of the liquid crystal sealing member 25.

The operation of the display device during photographing by the camera will be described in more detail with reference to FIGS. When the release button is half-pressed, focus detection is performed in any of the selected focus detection areas. At this time, a voltage is applied to the pair of electrodes of the display notch located in the selected focus detection area, and the refractive index of the liquid crystal interposed in the notch increases. At the same time, the LEDs 26a to 26c are turned on, and the illumination light enters from the end face of the transparent flat plate 23.
As described above, the illumination light is reflected twice and emitted vertically only at the notch portion having a large refractive index, and the mark of the focus detection area is displayed in the finder with the mark of the focus detection area sparsely imposed on the background image. At this time, by turning on / off the voltage applied to the electrode periodically or turning on / off the LED at a predetermined cycle, the display mark blinks and the visibility can be improved.

Since no voltage is applied to the electrodes in the non-selected focus detection area, the refractive index of the liquid crystal in that part is substantially equal to the refractive index of the transparent flat plate, and the illumination light is reflected at the cut portion. In addition, the light flux of the background image passes through the transparent flat plate 23 and the liquid crystal sealing member 25 and is emitted from the display device without being affected by the cut portion.

Further, if a voltage is applied to the electrode in the cut portion corresponding to the focus detection area to display the focus detection area mark after the end of the focus detection operation, the focus detection area is set at the start and end of the focus detection. It is displayed and operability is good. Further, the operability is further improved by selectively using the color of the light projected from the LED at the start and end of the focus detection, for example, green at the start and red at the start.

Instead of the light source 26 using the three LEDs 26a to 26c, a linear light source 36 as shown in FIG.
May be used. Also, as shown in FIG.
The illumination light projected from 6a is converted to a cylindrical lens 46.
The light may be made into parallel light by b, and the illumination light may efficiently travel through the waveguide inside the transparent flat plate 23 and the liquid crystal sealing member 25.

In the above description, the refractive index of the liquid crystal is 1.53
It is assumed that the refractive index when no voltage is applied is approximately equal to the refractive index of the transparent flat plate 23. However, even when no voltage is applied to the liquid crystal, the illumination light is slightly reflected at the cut portion so that it can be visually recognized. Alternatively, the refractive index of the liquid crystal when no voltage is applied may be made larger than the refractive index of the transparent flat plate 23 within a range where total reflection is not performed. In this case, if the refractive index of the liquid crystal is set to, for example, 1.6 to 1.8, the critical angle of total reflection at a refractive index of 1.6 without application of voltage is 17 degrees, and there is no total reflection. The focus detection area mark can be reflected and constantly displayed faintly.

As described above, the light totally reflected at the cut portion is displayed as a mark in the finder.
In some cases, the photographer may feel dazzling. In that case, the reflection surface of the cut is made to be a scattering surface, and the light flux superimposed on the background image is diffused, so that the amount of light is reduced, but so-called "soft light" can be obtained.

When it is difficult to manufacture the first and second reflecting surfaces shown in FIG. 4, the cut portion is formed by a cutout 44A of a quarter spherical surface as shown in FIG. The cut 44B may be a 1/2 spherical surface as shown. In the case of a spherical surface, the illumination light is emitted vertically from the emission surfaces of the liquid crystal sealing members 45A and 45B while repeating total reflection up to a critical angle at the interface. In FIGS. 10A and 10B, 43
A and 43B are transparent flat plates, and 47a and 47b are transparent electrodes. Although the reflecting surface is approximately spherical, it is preferable to use an asteroid curve.

FIGS. 11A and 11B are diagrams showing an example of the case where characters, symbols, and the like are displayed on the display device according to the present invention. As shown in FIG. 11B, a plurality of grooves 54 having a rectangular shape in plan view and a saw-tooth shape in cross section are engraved as transparent segments on the transparent flat plate 53. The groove 54 is shown in FIG.
As shown in (b), one side surface is provided inclined, and when a voltage is applied to the electrode corresponding to the groove 54 of the liquid crystal 55, the illumination light from the LEDs 56a and 56b is totally reflected by the groove 54. The numeral "8" is displayed, and if a voltage is applied only to the selected electrode, the desired numeral is displayed. If the illuminating light from the light sources 56a and 56b is inclined with respect to the groove 54, the angle of the luminous flux seen in the groove becomes shallower, and a margin to the critical angle can be obtained. By doing so, the so-called “display viewing angle” is widened.

In addition to the finder display device of the camera, the display device of the present invention can be used as a display device of various image input devices, and can also be used as a display device for displaying vehicle speed, time, and the like on a front shield window of a vehicle. . Further, it can be used as a display device for displaying a clock and various information on a window. In such a case, as shown in FIG. 12, it is preferable to improve the visibility by providing a diffusion plate 67 in the surface region of the liquid crystal sealing member 65 corresponding to the cut 64 of the transparent flat plate 63.

In the above description, illumination light is emitted using a light emitting element such as an LED, but natural light may be incident on a transparent flat plate and used as a display light source. In the above-described embodiment, the transparent flat plate is arranged on the incident side of the background image,
Although the refractive index changing members are arranged on the exit side of the superimposed image, they may be arranged in reverse.

[0028]

【The invention's effect】

(1) According to the present invention, by reflecting illumination light incident from the side of a flat plate at an interface where the refractive index changes from large to small, a figure, a character,
Since a luminous flux such as a symbol is generated and emitted, a new display device that solves the problems of the light-shielded or illuminated display device can be provided. (2) If the refractive index of the flat plate is made smaller than that of the first reflecting surface as in the invention of claim 4, a part of the light incident on the flat plate from the side is always reflected, and the reflected light of the information image is reflected on the background It can always be displayed over the image. (3) If the incident light is reflected by the first and second reflecting surfaces as in the invention of claim 5, the second refractive index of the refractive index variable member is much smaller than the refractive index of the flat plate. Even if the size cannot be increased, the reflected light of the information image can be made substantially coincident with the emission direction of the background image.

[Brief description of the drawings]

FIG. 1 is a plan view of a display field for explaining a principle of a display device of the present invention.

FIG. 2 is a cross-sectional view of the display device of FIG. 1 taken along the line II-II.

FIG. 3 is a diagram illustrating a critical angle at which illumination light of a display device according to the present invention is totally reflected.

FIG. 4 is a diagram illustrating a reflection surface of an interface for correcting the direction of emission light from which illumination light is totally reflected in the display device according to the present invention.

FIG. 5 is a diagram illustrating that incident light is reflected twice and emitted vertically.

FIG. 6 is a perspective view illustrating a case where the present invention is applied to a finder display device of a camera.

7 is a plan view of a display field of viewfinder display device of FIG. 7;

FIG. 8A is a view VIII- showing a cut of the display device of FIG. 7;
FIG. 8B is a cross-sectional view taken along the line VIII, and FIG.

FIG. 9 is a perspective view showing another example of the light source.

FIG. 10 is a cross-sectional view showing another example of the cut.

FIG. 11A is a plan view of a display device that displays characters,
(B) is a sectional view taken along the line bb.

FIG. 12 is a cross-sectional view when a diffusion plate is provided on the surface of a liquid crystal sealing member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Field of view 12 Display mark 13, 23 Transparent flat plate 14, 24 Cut 14a, 14b First and second reflective surface 15, 25 Liquid crystal sealing member 16, 26, 36, 46, 56a, 56b Light source

Claims (5)

[Claims] 1. A display device in which information images such as figures, characters, and symbols are superimposed on a background image incident from one surface and output from the other surface, wherein a space corresponding to the information image is provided. A flat plate formed therein, and a refractive index variable member provided inside the space and having a changeable refractive index, the illumination light incident from the side of the flat plate being more than the refractive index of the flat plate. By making the refractive index incident on the variable-refractive-index member having a large refractive index, reflecting the incident light at the interface between the variable-refractive-index member and the flat plate, the figure, the character, the luminous flux corresponding to the symbol, and the like to the background image. A display device configured to be superimposed. 2. The display device according to claim 1, wherein the variable refractive index member has a first refractive index to a second refractive index (> 2).
The display device, wherein the refractive index is adjusted within a range of (first refractive index), and the flat plate has a refractive index smaller than at least the second refractive index. 3. The display device according to claim 2, wherein a refractive index of said flat plate is substantially equal to said first refractive index. 4. The display device according to claim 2, wherein a refractive index of the flat plate is smaller than the first refractive index, and a part of the incident light from the side is constantly reflected to superimpose a background image. A display device characterized in that it is imposed. 5. The display device according to claim 1, wherein said incident light is sequentially reflected such that reflected light from said interface is emitted substantially perpendicularly from said other surface. And a second reflection surface provided at the interface.