DISPLAY ASSEMBLY

Abstract

The present invention concerns a display assembly comprising an organic light-emitting diode display device comprising at least one OLED comprising an emitting stack placed on a transparent substrate, whose back face is placed on the emitting surface of the OLED, and a secondary object to be illuminated, said transparent substrate comprising a front face and at least one side face arranged to light a secondary object.

Claims

1. A display assembly comprising an organic light-emitting diode display device comprising at least one OLED comprising an emitting stack placed on a transparent, semi-transparent or translucent substrate, whose back face is placed on the emitting surface of the OLED, and a secondary object to be illuminated, said transparent substrate comprising a front face and at least one side face arranged to light a secondary object.

2. An assembly according to any of the preceding claims comprising an analogue time display.

3. The assembly according to claim 2, wherein the secondary object includes the analogue time dial.

4. The assembly according to claim 1, wherein the secondary object is arranged inside a watch aperture.

5. The assembly according to claim 1, wherein said side face is depolished to produce diffused light during use.

6. A positive assembly according to claim 1, wherein said side face is at an angle of between 90 and 135 relative to the front face.

7. An assembly according to claim 1, wherein said transparent substrate has a refractive index of at least 1.5 and preferably comprised between 1.6 and 1.8.

8. The assembly according to claim 1, wherein opaque covers are arranged on the side faces that do not illuminate the secondary object.

9. The assembly according to claim 1, wherein the front face of the substrate includes an integrated or added decoration.

10. The assembly according to claim 1, wherein the substrate is surmounted by a semi-transparent dial.

11. A watch including a display assembly comprising an organic light-emitting diode display device comprising at least one OLED comprising an emitting stack placed on a transparent, semi-transparent or translucent substrate, whose back face is placed on the emitting surface of the OLED, and a secondary object to be illuminated, said transparent substrate comprising a front face and at least one side face arranged to light a secondary object.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 represents a perspective view of a watch including a display assembly according to the invention.

[0016] FIG. 2 represents a cross-sectional view of a watch including a display assembly according to the invention represented in FIG. 1.

[0017] FIG. 3 represents an enlargement of area 10 of FIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

[0018] It is an object of the present invention to propose a display assembly comprising an organic light-emitting diode (OLED) display device A, used for displaying information on demand to the user, and a secondary object 6 to be illuminated, which makes the best use of the light emitted by one or more OLEDs of OLED display device A, trapped between the faces of the substrate of the device and recovered to illuminate the secondary object 6 associated with the OLED device.

[0019] According to an embodiment of the invention represented in FIGS. 1 to 3, a watch M is shown incorporating a mixed display device comprising an active lighting screen A (backlit, LED or OLED), which can be decorated on the face thereof oriented towards the user, and a passive display comprising a time dial cooperating with hands 11 and a passive display member 6 visible through an aperture 7 arranged in the dial.

[0020] As represented in FIG. 3, the display assembly of the invention uses the light trapped by total reflection in a transparent layer 2 of the active display by extracting the light through a side face 8 substantially perpendicular to the main faces or at an angle comprised between 90 and 135 relative to the front face. The active display device of the invention comprises an emitting layer of the OLED type 1 placed on the back face of transparent substrate 2. This may be an active matrix OLED screen, or a liquid crystal screen (LCD) particularly of the TFT type, associated with a backlight device comprising an OLED or a LED. In this latter case, the light is recovered from the side faces of the light guide of the backlight device. In the present description, this screen is assumed to be the main display.

[0021] In such a device, only light 4 emitted by the OLED forming an angle to the surface normal of the display glass lower than the critical angle, can emerge from the front face of the transparent substrate.

[0022] According to the invention, part of light 5 trapped between the parallel faces of transparent substrate 2 by total reflection is extracted through at least one side face 8 made in the selected area. This light can then be used to light other elements 6, referred to as secondary elements, such as an analogue time display or a display member visible through aperture 7, for example a date disc 6.

[0023] It is possible to modify the ratio between the light emitted by the front face and the light emitted by the edge or side face of the substrate by modifying the refractive index of the substrate: the higher the refractive index of the substrate, the more light will be trapped in transparent layer 2. It may, from this point of view, be advantageous to use a high index substrate 2, such as sapphire, whose refractive index is 1.768.

[0024] One or more additional layers 3 can be added to the surface of transparent substrate 2. These layers can, for example, act as anti-scratch, anti-reflective or decorative layers.

[0025] Side faces 8 of substrate 2 preferably have a texture that reduces internal reflection, to optimise light extraction. In particular, water jet, grinding or ultrasonic cutting techniques have the advantageous effect of frosting on depolishing the side 8 of substrate 2, thereby improving diffusion and thus the uniformity of light extraction.

[0026] Depending upon the position of the secondary object 6 to be illuminated, it may be advantageous to incline lighting side 8. In particular, as represented in FIG. 1, an object slightly set back from the main display, as would be the case of a conventional date display via a mechanically driven date disc (see FIGS. 2 and 3), is, preferably, illuminated by side faces oriented towards this secondary display, which has the additional advantage of reducing the direct view to the user, and therefore of reducing glare.

[0027] To prevent undesired illumination, the side faces which do not illuminate a secondary object can advantageously be covered with an opaque, preferably reflective layer 9.

[0028] As represented in FIGS. 2 and 3, the organic light-emitting diode (OLED) display device of the invention is advantageously incorporated in mixed watches, comprising a conventional time display including hands 11 and an aperture 7 underneath which a date disc 6 is driven. In such case, the hands are back lit by the main OLED display device which forms a dial located behind the hands, whereas aperture 7 is lit by side faces 8 of aperture 7 arranged in substrate 2 of the organic light-emitting diode (OLED) display device of the invention.