DISPLAY UNIT AND METHOD FOR OPERATING A DISPLAY UNIT

Abstract

Described herein is a display unit (1) comprising a pixel-matrix (11) with multiple pixels (110) and at least one refractive optical element (12) having a refractive power, wherein the pixels (110) are arranged to emit light having a definable color and intensity, the light emitted by the pixel-matrix (11) passes through the refractive optical element (12), and the refractive power is tunable.

Claims

1. Display unit comprising a pixel-matrix with multiple pixels and at least one refractive optical element having a refractive power, wherein the pixels are arranged to emit light having a definable color and intensity, the light emitted by the pixel-matrix passes through the refractive optical element, and the refractive power is tunable.

2. Display unit according to claim 1, wherein the refractive optical element is a tunable lens or a tunable lens array, the tunable lens or each lens of the tunable lens array comprises exactly one tunable surface or exactly two tunable surfaces, wherein the refractive power is tunable by changing the curvature of the tunable surface or the tunable surfaces.

3. Display unit according to claim 2, wherein the pixels are arranged in a first plane, the lenses of the lens array are arranged in a second plane, and the lenses are arranged at the corner points of an imaginary repetitive hexagonal line pattern, at the corner points of an imaginary repetitive rectangular line pattern or along the lines of an imaginary concentric circular pattern.

4. Display unit according to claim 1, wherein the refractive power of the optical element may be tuned in a range −40 diopters to +30 diopters.

5. Display unit according to claim 1, wherein the refractive power of the optical element may be tuned with a display frequency of at least 45 Hz, preferably at least 60 Hz.

6. Display unit according to claim 5, wherein the pixels are arranged to emit light of a definable color and intensity in an on-state and the pixels do not emit light in an off-state, the pixels are arranged to be switched into the on-state for a definable timespan, while the refractive power of the optical element is in a designated range and the refractive power is tuned with the display frequency.

7. Display unit according to claim 1, wherein the display unit is a virtual reality display, in particular a head mounted virtual reality display unit.

8. Display unit according to claim 1, wherein each pixel comprises a micro LED.

9. Method for operating a display unit, wherein the display unit comprises a pixel matrix with multiple pixels and at least one refractive optical element, wherein the refractive optical element has a refractive power, which is tunable, comprising the steps of, a) tuning the refractive optical power in an oscillating manner; b) switching the pixels from an off-state in an on-state for a definable time span, when the refractive power is within a dedicated range, wherein the pixel emits light of definable color and intensity in the on-state and the pixel does not emit light in the off-state.

10. Method according to claim 9, wherein in method step a) the refractive power is tuned with a frequency of at least 45 Hz, in particular at least 60 Hz, and an amplitude of at least 5 diopters in particular at least 10 diopters.

11. Method according to claim 9, wherein the refractive power set to an offset value, and the refractive power oscillates around said offset value in method step a).

12. Method according to claim 11, wherein the offset value is between −40 and +30 diopters and the offset value depends on the ametropia of the person using the display unit.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0028] FIGS. 1, 2, 3 and 4 show exemplary embodiments of display units in sectional views;

[0029] FIGS. 5, 6 and 7 show exemplary embodiments of refractive elements of display units in top views.

DETAILED DESCRIPTION

[0030] Further advantages and advantageous refinements and developments of the display unit and the method for operating the display unit result from the following exemplary embodiments illustrated in connection with the figures.

[0031] Identical, identical or identically acting elements are provided with the same reference symbols in the figures. The figures and the proportions of the elements shown in the figures among one another are not to be regarded as to scale. Rather, individual elements may be exaggerated in size for better displayability and/or for better comprehensibility.

[0032] FIG. 1 shows an exemplary embodiment of a display unit 1 comprising a pixel-matrix 11 and a refractive optical element 12. The refractive optical power of the optical element 12 is tunable. When operating the display unit 1, the optical power of the optical element 12 is tuned to an offset value between −40 diopters and +30 diopters. The offset value may be selected such that ametropia of a user 2 utilizing the display unit 1 is compensated. When operating the display unit, the optical power is modulated with a display frequency. The display frequency may be at least 50% or at least 100% of the refresh rate of the pixel-matrix 11. For example, the refresh rate is at least 90 Hz, in particular at least 120 Hz.

[0033] FIG. 2 shows an exemplary embodiment of a display unit 1. In this embodiment, the pixel-matrix 11 comprises multiple pixels 110, wherein each pixel consists of subpixels 1100. The subpixels 1100 of a pixel 110 are arranged to emit light of different wavelength ranges. Thus, each pixel 110 may emit additively mixed light of a desired color and intensity. For example, the subpixels 1100 are arranged to emit light in a red, green or blue wavelength range. In particular, each subpixel 1100 comprises a micro-LED.

[0034] The refractive optical element 12 comprises a tunable lens 120 having exactly one tunable optical surface 122. The tunable lens 120 comprises a lens shaper 121, a membrane and a liquid 123. The lens shaper 121 is arranged to push against a membrane, whereby the pressure of the liquid 123 is increased. Increased pressure of the liquid results in an increased curvature of the tunable optical surface 122. In operation, the light emitted by the pixel-matrix 11 goes through the refractive optical element 12 and is refracted at the tunable optical surface 122.

[0035] FIG. 3 shows an exemplary embodiment of a display unit 1 having exactly two tunable surfaces 122. The curvature of each tunable surface is controlled by means of a lens shaper 121. The lens shaper 121 respectively has an opening, into which the membrane expands, when the pressure of the liquid 123 is increased.

[0036] FIG. 4 shows an exemplary embodiment of a display unit, wherein the refractive optical element comprises a lens array with tunable lenses. The refractive optical element has exactly two tunable optical surfaces 122. Each tunable optical surface is part of a flexible membrane. Each tunable surface 122 is in direct contact with a lens shaper 121. The lens shaper 121 has a mesh structure, wherein openings in the mesh structure define the aperture of each lens of the tunable lens array. The openings may have a circular contour having a diameter of 2 millimeters.

[0037] FIG. 5 shows an exemplary embodiment of a refractive optical element 12 in a top view. The opticl element 12 comprises a lens array, with multiple lenses 12 which a arranged in a common plane. The lenses are defined by openings in the lens shaper 121. For example the openings have a diameter of about 2 mm. In the exemplary embodiment, the lenses 120 are arranged at the edges of an imaginary rectangular gridlines. Alternatively, the lenses 120 may be arranged at the edges of imaginary hexagonal gridlines.

[0038] FIG. 6 shows an exemplary embodiment of a refractive optical element 12 in top view. The exemplary embodiment of FIG. 6 differs from the exemplary embodiment of FIG. 5 in the arrangement of the lenses 120.

[0039] FIG. 7 shows an exemplary embodiment of a refractive optical element 12 in top view. The exemplary embodiment of FIG. 7 differs from the exemplary embodiment of FIGS. 5 and 6 in the arrangement of the lenses 120. The lenses 120 are arranged on imaginary circular lines in a concentric manner.

[0040] The invention is not restricted to the exemplary embodiments by the description based on these. Rather, the invention encompasses every new feature and every combination of features, which in particular includes every combination of features in the patent claims, even if this feature or this combination itself is not explicitly specified in the patent claims or exemplary embodiments.”

LIST OF REFERENCE NUMBERS

[0041] 1 display unit

[0042] 11 pixel-matrix

[0043] 110 Pixel

[0044] 1100 Subpixel

[0045] 12 refractive optical element

[0046] 120 Lens

[0047] 121 lens shaper

[0048] 122 tunable optical surface

[0049] 123 Liquid

[0050] 2 User