TWI738356B - Holographic display device - Google Patents

Abstract

The present disclosure provides a holographic display device, including: a display module for emitting at least a first color light and a second color light, a luminous efficiency of the first color light is higher than that of the second color light; and a diffraction module on exit paths of the first color light and the second color light, the diffraction module is configured to diffract the first color light with a first diffraction efficiency, and diffract the second color light with a second diffraction efficiency, so as to generating a holographic image. The first diffraction efficiency is smaller than the second diffraction efficiency.

Description

Holographic display device

The invention relates to the field of holographic display, in particular to a holographic display device.

The holographic display method combines holographic technology and waveguide technology to achieve the purpose of superimposing the virtual image with the external scene image in a projection manner.

The holographic products in the prior art include a head-mounted holographic display, and the user can see a three-dimensional holographic image by wearing it on the head. In the holographic display, light sources of various colors are diffracted by a diffraction structure to obtain a diffracted image. However, the source light usually includes multiple colors of light. The diffraction efficiency of colored light is different, which often results in color shift and image distortion in the finally obtained diffraction image.

One aspect of the present invention provides a holographic display device, including: a display module for emitting at least a first color light and a second color light, the luminous efficiency of the first color light is higher than the luminous efficiency of the second color light And a diffraction module, the diffraction module is arranged on the exit path of the first color light and the second color light for diffracting the first color light with a first diffraction efficiency, The second color light is diffracted with a second diffraction efficiency to generate a holographic image, wherein the first diffraction efficiency is less than the second diffraction efficiency.

According to the above-mentioned holographic display device, according to the luminous efficiency of the first color light and the second color light, the characteristics and matching sequence of the first diffraction element and the second diffraction element in the diffraction module are correspondingly set to reduce the first color light The difference in luminous intensity between the second color light and the second color light is beneficial to improve the color shift problem of the holographic image generated by the holographic display device and avoid the distortion of the holographic image.

10: Holographic display device

20: display module

21: Light-emitting components

22: Color conversion layer

221: first conversion unit

222: The second conversion unit

223: Transmission unit

23: substrate

30: Diffraction module

31: The first diffraction unit

311, 321: first diffraction component

312, 322: second diffraction component

313, 323: third diffraction component

32: The second diffraction unit

40: Optical waveguide

FIG. 1 is a schematic diagram of the structure of a holographic display device according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of the structure of the display module in FIG. 1.

This embodiment provides a holographic display device. Specifically, the holographic display device is a head-mounted holographic display device. When the holographic display device is worn on the user's head, it can show the user a three-dimensional holographic image.

Please refer to FIG. 1, the holographic display device 10 provided in this embodiment includes a display module 20, a diffraction module 30, and an optical waveguide 40 arranged between the display module 20 and the diffraction module 30. The display module 20 is used for emitting the first color light, the second color light and the third color light. In other embodiments, the display module 20 is used to emit the first color light and the second color light. The diffraction module 30 is configured to diffract and emit the first color light, the second color light, and the third color light. As a light propagation medium, the optical waveguide 40 is arranged on the emission paths of the first color light, the second color light, and the third color light, and is used to guide the first color light, the second color light, and the second color light. The color light and the third color light propagate between the display module 20 and the diffraction module 30, and combine the first color light, the second color light, and the third color light after being diffracted by the diffraction module 30 Shoot out. In this embodiment, the optical waveguide 40 can be made of transparent optical glass or optical plastic.

Referring to FIG. 2, the display module 20 includes a substrate 23 and a plurality of light-emitting elements 21 disposed on the same surface of the substrate 23, and each light-emitting element 21 is used to emit the first color light. In this embodiment, each light-emitting component 21 is a Micro Light-Emitting Diode (Micro-LED); each light-emitting component 21 is used to emit blue light, that is, the first color light is blue light.

Referring to FIG. 2, the display module 20 further includes a color conversion layer 22, which is disposed on the exit path of the first color light, and is used to convert part of the first color light into the second color The light converts part of the first color light into the third color light, and is used to directly transmit the remaining first color light. In this embodiment, the second color light is green light, and the third color light is red light. In this embodiment, the color conversion layer 22 is a quantum dot layer. The color conversion layer 22 includes a plurality of first conversion units 221, a plurality of second conversion units 222, and a plurality of transmission units 223. Contains different types of quantum dots, the transmission unit 223 does not include quantum dots, each first conversion unit 221 is used to convert part of the first color light into the second color light, and each second conversion unit 221 The unit 222 is used to convert part of the second color light into the third color light, and each transmission unit 223 is used to directly transmit the remaining first color light that is not converted.

Among the first color light, the second color light, and the third color light emitted from the color conversion layer 22, the first color light is directly emitted from the transmission unit 223 without the color conversion layer 22 without undergoing color conversion. The second color light and the third color light are obtained by color conversion of the first color light emitted by each light-emitting component 21, and then among the first color light, the second color light, and the third color light emitted from the color conversion layer 22, The luminous efficiency of the first color light is higher than the luminous efficiency of the second color light and the third color light. According to the properties of different types of quantum dots, the color conversion efficiency of the quantum dots in each first conversion unit 221 is higher than the color conversion efficiency of the quantum dots in each second conversion unit 222, so the luminous efficiency of the second color light Higher than the luminous efficiency of the third color light.

When the light-emitting components 21 are driven to emit light with a preset driving voltage, the measured luminous intensity of the first color light emitted from the color conversion layer 22 is A ₁ , the luminous intensity of the second color light is A ₂ , and the third color light The luminous intensity of is A ₃ , and the luminous efficiency is proportional to the luminous intensity, then A ₁ >A ₂ >A ₃ . Since the luminous efficiency of the first color light, the second color light and the third color light are different, that is, the luminous intensity is different, it is easy to cause color shift in the holographic image generated by the holographic display device 10, which affects the image display effect.

In this embodiment, the above-mentioned color shift problem is improved by the diffraction module 30.

Please refer to FIG. 1 again, the diffraction module 30 is disposed on the side of the optical waveguide 40 away from the display module 20. The diffraction module 30 includes a first diffraction unit 31 and a second diffraction unit 32 spaced apart from each other. The first diffracting unit 31 is used to diffract the first color light, the second color light, and the third color light for the first time, and the second diffracting unit 32 is used to diffract the first color light, the second color light, and the first color light. The three-color light is diffracted for the second time to generate the holographic image. The optical waveguide 40 is used to guide the first color light, the second color light, and the third color light in the display module 20 and the first diffraction unit. 31 and the second diffraction unit 32 propagate between.

Please continue to refer to FIG. 1, the first diffraction unit 31 includes a first diffraction element 311, a second diffraction element 312, and a third diffraction element 313. In this embodiment, the first diffraction element 311, the second diffraction element 312, and the third diffraction element 313 are diffraction gratings. The first diffraction element 311, the second diffraction element 312, and the third diffraction element 313 are stacked in sequence. The first diffractive component 311 is used to diffract the first color light, the second diffractive component 312 is used to diffract the second color light, and the third diffractive component 313 is used to diffract the third color light.

It should be understood that in this embodiment, the first diffractive element 311 is mainly used to diffract the first color light, but the second color light and the third color light both pass through the first diffractive element 311, so the first diffractive element 311 311 also has a certain diffracting effect on the second color light and the third color light, but the diffracting effect of the first diffractive component 311 on the first color light is much greater than that of the second color light and the third color light. Shooting effect. Similarly, the second diffractive component 312 is mainly used to diffract the second color light, and the diffracting effect of the second diffractive component 312 on the second color light is much greater than that on the first color light and the third color light. The third diffractive component 313 is mainly used to diffract the third color light, and the third diffractive component 313 has a much greater diffracting effect on the third color light than on the first color light and the second color light effect.

That is, the first color light, the second color light, and the third color light are all absorbed by the first diffraction element 311, the second diffraction element 312, and the third diffraction element 313 in the first diffraction unit 31. Define the total diffraction efficiency of the first diffraction element 311, the second diffraction element 312, and the third diffraction element 313 for the first color light as the diffraction efficiency of the first diffraction unit 31 for the first color light; Definition The total diffraction efficiency of the first diffraction element 311, the second diffraction element 312, and the third diffraction element 313 for the second color light is the diffraction efficiency of the first diffraction unit 31 for the second color light; The total diffraction efficiency of the first diffraction element 311, the second diffraction element 312, and the third diffraction element 313 for the third color light is the diffraction efficiency of the first diffraction unit 31 for the third color light.

The luminous intensity after light is diffracted by the first diffractive unit 31 is the product of the luminous intensity before the light is incident on the first diffractive unit 31 and the diffraction efficiency of the first diffractive unit 31. Define the diffraction efficiency of the first diffraction unit 31 for the first color light as η ₁ %, and the luminous intensity of the first color light after being diffracted by the first diffraction unit 31 is A ₁₁ ; define the first diffraction unit 31 pair The diffraction efficiency of the second color light is η ₂ %, and the luminous intensity of the second color light after being diffracted by the first diffraction unit 31 is A ₂₂ ; defines the diffraction efficiency of the first diffraction unit 31 for the third color light Is η ₃ %, and the luminous intensity of the third color light after being diffracted by the first diffracting unit 31 is A ₃₃ . Then: A ₁₁ =A ₁ *η ₁ %, A ₂₂ =A ₂ *η ₂ %, A ₃₃ =A ₃ *η ₃ %.

In this embodiment, the stacking sequence among the first diffractive element 311, the second diffractive element 312, and the third diffractive element 313 affects the first diffractive unit 31 for the first color light, the second color light, and the third diffractive element. The diffraction efficiency of color light has an influence. Therefore, by adjusting the stacking sequence among the first diffraction element 311, the second diffraction element 312, and the third diffraction element 313, the first diffraction unit 31 can adjust the first color light, the second color light, and the Diffraction efficiency of the third color light. In this embodiment, the stacking sequence among the first diffraction element 311, the second diffraction element 312, and the third diffraction element 313 is determined according to the luminous efficiency of the first color light, the second color light, and the third color light. That is, the stacking order among the first diffractive element 311, the second diffractive element 312, and the third diffractive element 313 is determined according to the luminous intensity of the first color light, the second color light, and the third color light. Specifically, when A ₁ >A ₂ >A ₃ , adjust the stacking order among the first diffraction component 311, the second diffraction component 312, and the third diffraction component 313 so that η ₁ %<η ₂ %<η ₃ %.

Since A ₁ >A ₂ >A ₃ and η ₁ %<η ₂ %<η ₃ %, the first color light, the second color light, and the third color light pass through the first diffraction component 311 and the second diffraction element After the component 312 and the third diffraction component 313 are diffracted, _{the difference between the luminous intensities A 11} , A ₂₂ and A ₃₃ is smaller than the difference between the luminous intensities A ₁ , A ₂ and A ₃ .

Therefore, in the holographic display device 10 provided in this embodiment, according to the luminous efficiency of the first color light, the second color light, and the third color light, the first diffraction component 311 and the second diffraction component in the diffraction module 30 are arranged 312 and the third diffractive component 313 are stacked in order to adjust the first diffractive component 311, the second diffractive component 312 and the third diffractive component 313 to the first color light, the second color light and the third color The diffraction efficiency of light, so as to adjust the luminous intensity of the first color light, the second color light, and the third color light after being diffracted by the first diffraction element 311, the second diffraction element 312, and the third diffraction element 313 In order to reduce the difference in luminous intensity between the first color light, the second color light, and the third color light, it is beneficial to improve the color shift of the holographic image generated by the holographic display device 10 and avoid image distortion.

Please continue to refer to FIG. 1, the second diffraction unit 32 includes a first diffraction element 321, a second diffraction element 322 and a third diffraction element 323. The stacking sequence among the first diffraction component 321, the second diffraction component 322 and the third diffraction component 323 is the same as the stacking sequence in the first diffraction unit 31. In other embodiments, the stacking sequence among the first diffraction element 321, the second diffraction element 322 and the third diffraction element 323 may be different from the stacking sequence in the first diffraction unit 31. The first diffractive component 321 is used to diffract the first color light emitted from the first diffractive unit 31, the second diffractive component 322 is used to diffract the second color light emitted from the first diffractive unit 31, and the third The diffractive component 323 is used to diffract the third color light emitted from the first diffractive unit 31. By arranging the stacking sequence of the first diffraction element 321, the second diffraction element 322, and the third diffraction element 323 in the second diffraction unit 32, the first diffraction element emitted from the second diffraction unit 32 can be further reduced. The difference in luminous intensity between the first color light, the second color light, and the third color light is beneficial to further improve the color shift of the holographic image generated by the holographic display device 10. I won't repeat them here.

Those of ordinary skill in the art should realize that the above embodiments are only used to illustrate the present invention, and not to limit the present invention. As long as they fall within the essential spirit of the present invention, the above embodiments are appropriately made. Changes and changes fall within the scope of protection of the present invention.

10: Holographic display device

20: display module

30: Diffraction module

31: The first diffraction unit

311, 321: first diffraction component

312, 322: second diffraction component

313, 323: third diffraction component

32: The second diffraction unit

40: Optical waveguide

Claims (9)

A holographic display device, which is improved by comprising: a display module for emitting at least a first color light and a second color light, the luminous efficiency of the first color light is higher than the luminous efficiency of the second color light; And a diffraction module, which is arranged on the exit paths of the first color light and the second color light, and is used to diffract the first color light with the first diffraction efficiency, and The second color light is diffracted with a second diffraction efficiency to generate a holographic image, wherein the first diffraction efficiency is lower than the second diffraction efficiency; the display module includes: a plurality of light-emitting components, For emitting the first color light; and a color conversion layer, arranged on the exit path of the first color light, for converting part of the first color light into at least the second color light. The holographic display device according to claim 1, wherein the display module is also used to emit a third color light, and the diffraction module is also used to diffract the third color light with a third diffraction efficiency The luminous efficiency of the second color light is higher than the luminous efficiency of the third color light, and the second diffraction efficiency is lower than the third diffraction efficiency. The holographic display device according to claim 2, wherein the diffraction module includes a first diffraction element, a second diffraction element, and a third diffraction element that are sequentially stacked; the first diffraction element is used for To diffract the first color light, the second diffractive element is used to diffract the second color light, and the third diffractive element is used to diffract the third color light. The holographic display device according to claim 3, wherein the holographic display device includes a first diffraction unit and a second diffraction unit that are independent of each other, and each of the first diffraction unit and the second diffraction unit It includes a first diffractive component, a second diffractive component, and a third diffractive component; the first color light, the second color light, and the third color light pass through the The first diffraction unit performs the first diffraction, and then the second diffraction unit performs the second diffraction to generate the holographic image. The holographic display device according to claim 4, wherein the holographic display device further includes an optical waveguide disposed between the display module and the diffraction module for guiding The first color light, the second color light, and the third color light propagate between the display module, the first diffraction unit, and the second diffraction unit. The holographic display device according to claim 3, wherein the first diffraction element, the second diffraction element, and the third diffraction element are all diffraction gratings. The holographic display device according to claim 1, wherein the color conversion layer is also used to convert part of the first color light into a third color light. The holographic display device according to claim 7, wherein the first color light is blue light, the second color light is green light, and the third color light is red light. The holographic display device according to claim 1, wherein the color conversion layer is a quantum dot layer.

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