Display system
A display system including a lightguide and first and second reflective layers disposed on opposite sides of the lightguide is provided. The lightguide has opposing first and second major surfaces and includes a light extraction pattern for extracting light that would otherwise be confined and propagate within the lightguide primarily by total internal reflection. Light extracted by the light extraction pattern exits the lightguide through at least one of the first and second major surfaces of the lightguide. Each of the first and second reflective layers has an average specular reflectance of at least 50% in a predetermined wavelength range. The light extraction pattern may be repeatedly imaged by the first and second reflective layers to produce three-dimensional stacked images of the light extraction pattern.
1. A display system, comprising:
a lightguide, comprising:
opposing first and second major surfaces and a first side surface at a first end of the lightguide extending between and joining the first and second major surfaces; and
a light extraction pattern for extracting light that would otherwise be confined and propagate within the lightguide primarily by total internal reflection, light extracted by the light extraction pattern exiting the lightguide through at least one of the first and second major surfaces of the lightguide; and
first and second reflective layers disposed on opposite sides of the lightguide adjacent the respective first and second major surfaces of the lightguide, an average specular reflectance of each of the first and second reflective layers being at least 50% in a predetermined wavelength range.
2. The display system of claim 1 , wherein the lightguide is sufficiently thin and the first and second reflective layers are sufficiently close to one another so that the light extraction pattern is repeatedly imaged by the first and second reflective layers to produce a substantially hall of mirrors effect.
3. The display system of claim 2 , wherein when a light source is disposed at the first side surface of the lightguide and light emitted by the light source enters the lightguide through the first side surface and propagates within the lightguide primarily by total internal reflection, the light extraction pattern extracts the propagating light, the light extraction pattern and the repeated images thereof being visible to a viewer from a predetermined viewing distance.
4. The display system of claim 1 , wherein light extracted by the light extraction pattern exiting the lightguide through at least one of the first and second major surfaces of the lightguide has a substantially non-uniform brightness distribution across the lightguide.
5. The display system of claim 1 , wherein an average specular transmittance of at least one of the first and second reflective layers is from about 1% to about 15% in the predetermined wavelength range.
6. The display system of claim 1 , wherein the average specular reflectance of one, but not the other, of the first and second reflective layers is at least 90% in the predetermined wavelength range.
7. The display system of claim 1 , wherein the predetermined wavelength range is in a visible range of the electromagnetic spectrum.
8. The display system of claim 1 further comprising a first light source disposed proximate the first side surface, light emitted by the first light source entering the lightguide through the first side surface and propagating within the lightguide primarily by total internal reflection, the light extraction pattern extracting the propagating light, the extracted light propagating toward a viewer at a predetermined viewing distance and making the light extraction pattern visible to the viewer without a vision aid.
9. A display system comprising a lightguide sandwiched between and substantially coextensive with substantially specularly reflective first and second reflective layers, such that when the display system is activated, a plurality of a same image is displayed stacked along a thickness direction of the lightguide, a brightness of the stacked images decreasing along the thickness direction.
10. The display system of claim 9 , wherein the lightguide has a round cross-sectional profile.
11. The display system of claim 9 , wherein the first and second reflective layers are substantially parallel, substantially coextensive and have a substantially uniform spacing of less than about 5 mm therebetween.
12. A display system comprising substantially parallel, coextensive first and second reflective layers having a substantially uniform spacing of less than about 5 mm therebetween, each reflective layer having an average specular reflectance of at least 85% in a predetermined wavelength range, at least one of the reflective layers having an average specular transmittance of about 1% to about 15% in the predetermined wavelength range.
13. The display system of claim 12 , wherein each reflective layer has an average specular reflectance of at least 90% in the predetermined wavelength range, and at least one of the reflective layers has an average specular transmittance of about 1% to about 10% in the predetermined wavelength range.
14. The display system of claim 12 , wherein each reflective layer has an average specular reflectance of at least 90% in the predetermined wavelength range, and at least one of the reflective layers has an average specular transmittance of about 1% to about 5% in the predetermined wavelength range.
15. The display system of claim 12 , wherein the first reflective layer is a first mirror and the second reflective layer is a second mirror separate from the first mirror.
16. The display system of claim 12 , wherein the first and second reflective layers are first and second portions of a continuous mirror.
17. The display system of claim 12 further comprising a lightguide disposed between the first and second reflective layers such that when the display system is activated, a plurality of a same image is displayed stacked along a thickness direction of the lightguide, a brightness of the stacked images decreasing along the thickness direction.