TWI714503B - Display apparatus - Google Patents

Abstract

A display apparatus includes a coherent light source, a display unit, a light-diffusing element, and at least one optical element. The coherent light source is configured to provide coherent light beams. The display unit is configured to form a three-dimensional image beam based on interference of the coherent light beams, wherein the three-dimensional image beam is imaged on an intermediate imaging surface after passing through the display unit. The light-diffusing element is located on the intermediate imaging surface, wherein a diffusion angle of the three-dimensional image beam is sequentially changed by passing through the light-diffusing element. The at least one optical element is located on a transmission path of the three-dimensional image beam from the light-diffusing element, and is configured to project the three-dimensional image light beam passing through the display unit out of the display apparatus to display a three-dimensional image.

Description

Display device

The present invention relates to a display device using coherent light beams, and more particularly to a display device using holography.

Three-dimensional (3D) display technology is applied in various image display fields, such as movies, television (television, TV), and mobile phones. Ultimately, the purpose of 3D display is to enable a person to experience 3D effects (as if he or she is in a real environment). Therefore, various technologies including stereophonic solutions and multi-view solutions have been researched. Holography is representatively used as a technique for restoring 3D spatial light information to the form of real light. Holography can restore light in space based on interference (ie, the waveform of light).

However, since the coherent light beams used in display devices using holography have high coherence, constructive or destructive interference is formed in space, and speckle-like speckles are generated on the illuminated surface. This kind of speckle is an irregular noise-like pattern with seemingly irregular bright and dark noise points, which will cause uneven brightness on the illuminated surface. Therefore, the image quality of the projection device using the light source is likely to be degraded, and the user's visual perception is deteriorated.

An existing method for eliminating speckle in general display devices using coherent light beams is to install a vibrating mirror in front of the coherent light source to homogenize the coherent light beam. However, because this method changes the spatial light information of the coherent light beam, it will It affects the formation of holograms, so it cannot be applied to display devices using holography.

The present invention provides a display device capable of providing images with good image quality.

The display device of the present invention includes a coherent light source, a display unit, a light diffusion element and at least one optical element. The co-tuned light source provides a co-tuned beam. The display unit forms a three-dimensional image beam based on the interference of the coherent beam, and the three-dimensional image beam is imaged on an intermediate imaging surface after passing through the display unit. The light diffusion element is arranged on the intermediate imaging surface, wherein the three-dimensional image beam passes through the light diffusion element to sequentially change the diffusion angle of the three-dimensional image beam. At least one optical element is located on the transmission path of the three-dimensional image beam from the light diffusion element, and is used to project the three-dimensional image beam passing through the display unit out of the display device to display the three-dimensional image.

In an embodiment of the present invention, the aforementioned light diffusing element has an actuator, and the actuator is electrically connected to the light diffusing element, and is used to drive the light diffusing element at a driving frequency.

In an embodiment of the present invention, the aforementioned actuator is used to drive the light diffusion element to vibrate, and the driving frequency is the vibration frequency of the light diffusion element.

In an embodiment of the present invention, the aforementioned actuator is used to drive the light diffusion element to rotate, and the driving frequency is the rotation frequency of the light diffusion element.

In an embodiment of the present invention, the above-mentioned light diffusion element is a liquid crystal element, and the light diffusion element includes a controller, and the controller controls the arrangement state of the liquid crystal molecules in the liquid crystal element to change with time.

In an embodiment of the present invention, the above-mentioned controller can control the light diffusion element to form a plurality of diffusion patterns, and each diffusion pattern is correspondingly formed in a different time sequence, and the liquid crystal molecules when the light diffusion element forms one of the diffusion patterns The arrangement state of and the arrangement state of liquid crystal molecules when the light diffusion element forms another diffusion pattern are different from each other.

In an embodiment of the present invention, the above-mentioned controller can control a diffusion pattern switching frequency of the light diffusion element. The diffusion pattern switching frequency is the frequency of the formation of multiple diffusion patterns per unit time, and when the type of the multiple diffusion patterns is In the case of N types, the range of the switching frequency is greater than N times of 60 Hz.

Based on the above, the display device of the embodiment of the present invention can adjust the overall uniformity of the three-dimensional image light beam through the configuration of the light diffusion element. Therefore, the three-dimensional image beam formed by the light diffusion element has good uniformity. In this way, the display device can provide a three-dimensional image showing uniform brightness, thereby improving the image quality and the user's visual perception.

FIG. 1 is a schematic structural diagram of a display device according to an embodiment of the invention. 1, in this embodiment, the display device 100 includes a coherent light source 110, a display unit 120, a light diffusion element 130 and at least one optical element 140. The co-tuned light source 110 is used to provide a co-tuned beam 50. For example, in this embodiment, the coherent light source 110 is a laser light source, and the display unit 120 can be a liquid-crystal-on-silicon panel (LCOS panel), which can be used to modulate the coherent light beam 50. Phase so that the coherent light beams 50 passing through the display unit 120 can form a three-dimensional image light beam 60 based on interference with each other. However, the present invention is not limited to this. In other embodiments, the display unit 120 may also be other beam modulators that can be used to modulate the phase of the co-modulated beam 50. As long as the display unit 120 can be used as a spatial light modulator and can have a structure capable of modulating the phase of the coherent light beam 50.

In addition, as shown in FIG. 1, in this embodiment, the display device 100 may further include a lens ML. Specifically, the lens ML can be arranged to correspond to each pixel on the display unit 120, and guide the coherent beam 50 to a specific position in the display unit 120, so that the coherent beam 50 can be effectively modulated into a three-dimensional image. The image beam 60, wherein the three-dimensional image beam 60 records the spatial light information required to form a three-dimensional image.

In this way, the display unit 120 can be used to form a three-dimensional image beam 60 based on the interference of the coherent beam 50, and, as shown in FIG. 1, the three-dimensional image beam 60 is imaged on an intermediate imaging surface IS after passing through the display unit 120 . More specifically, as shown in FIG. 1, in this embodiment, the light diffusion element 130 is also disposed on the intermediate imaging plane IS.

Furthermore, as shown in FIG. 1, in this embodiment, the light diffusion element 130 has an actuator 131, and the actuator 131 is electrically connected to the light diffusion element 130, and is used to drive the light diffusion element 130 at a driving frequency. . For example, the actuator 131 is used to drive the light diffusion element 130 to rotate, and the driving frequency is the rotation frequency of the light diffusion element 130.

In this way, the three-dimensional image light beam 60 passes through the light diffusion element 130 to sequentially change the diffusion angle of the three-dimensional image light beam 60. Moreover, due to the effect of persistence of vision, the brightness of the light spots on the illuminated surface as observed by the human eye will be the superimposed brightness of the light spots at different time points within the duration of the vision. Since the light diffusing element 130 can change the spot distribution of the three-dimensional image light beam 60 over time, but does not affect the spatial light information recorded by it, the light spots of the three-dimensional image light beam 60 passing through the light diffusing element 130 at different time points The distribution is not the same, but the three-dimensional image beam 60 can still retain its recorded spatial light information. Therefore, the superposition of the light spots at different time points in the visual duration will produce a light spot with a relatively uniform brightness, so that the three-dimensional image beam 60 formed by the light diffusion element 130 has better uniformity and still can It retains its recorded spatial light information and can display three-dimensional images smoothly.

Specifically, since the light diffusing element 130 is configured to sequentially change the diffusion angle of the three-dimensional image light beam 60, the size of the light diffusing element 130 is preferably slightly larger than that of the three-dimensional image light beam 60 on the intermediate imaging surface IS. The size of the upper part, so that the light diffusion element 130 can adjust the uniformity of the overall three-dimensional image beam 60. For example, in this embodiment, the size range of the light diffusing element 130 is greater than 1 cm.

Furthermore, as shown in FIG. 1, in this embodiment, at least one optical element 140 is located on the transmission path of the three-dimensional image beam 60 from the light diffusion element 130, and is used to transfer the three-dimensional image passing through the display unit 120 The light beam 60 is projected out of the display device 100 to display a three-dimensional image. For example, in this embodiment, the three-dimensional image light beam 60 passing through the intermediate imaging plane IS can be transmitted to the optical element 140, and projected out of the display device 100 through these optical elements 140 and then imaged again to display the three-dimensional image . The optical element 140 includes an optical element such as a concave mirror CM or a windshield WS. In this way, since the three-dimensional image beam 60 formed by the light diffusion element 130 has good uniformity, the display device 100 will also be able to provide a display screen with uniform brightness, thereby improving the image quality and the user's visual perception.

2A is a front view of an image provided by a conventional display device according to a comparative example. FIG. 2B is a front view of an image provided by the display device according to FIG. 1. FIG. The conventional display device for displaying the image of FIG. 2A is similar to the display device 100 of FIG. 1, but the difference is as follows. The conventional display device does not have the configuration of the light diffusing element 130. In this way, as shown in FIG. 2A, the image of the conventional display device has obvious light spots. In contrast, as shown in FIG. 2B, the image of the display device 100 is uniform and clear in brightness, and has good image quality. Improve the user's visual perception.

It is worth noting that in the foregoing embodiments, although the actuator 131 is used to drive the light diffusion element 130 to rotate as an example, the present invention is not limited thereto. In another embodiment, the actuator 131 can also drive the light diffusion element 130 to vibrate, so that the spot distribution of the three-dimensional image beam 60 changes with time. This will be further explained below.

FIG. 3 is a schematic structural diagram of a display device according to another embodiment of the invention. Please refer to FIG. 3. The display device 300 of FIG. 3 is similar to the display device 100 of FIG. 1, but the differences are as follows. The actuator 131 is used to drive the light diffusion element 130 to vibrate, and the driving frequency is the vibration frequency of the light diffusion element 130. In this way, the display device 100 can still adjust the uniformity of the overall 3D image beam 60 through the configuration of the light diffusion element 130, and the display device 300 can also achieve similar effects and advantages to the aforementioned display device 100. , I won’t repeat it here.

Furthermore, since the light diffusing element 130 of this embodiment vibrates to make the spot distribution of the three-dimensional image light beam 60 change over time, the moving range of the light diffusing element 130 is compared with that of rotating. Smaller. Therefore, the volume of the display device 300 can be further reduced.

4 is a schematic structural diagram of a display device according to another embodiment of the invention. Please refer to FIG. 4. The display device 400 of FIG. 4 is similar to the display device 300 of FIG. 3, but the differences are as follows. In this embodiment, the light diffusing element 430 is a liquid crystal element LC, and the light diffusing element 430 includes a controller 432, and the controller 432 controls the arrangement state of the liquid crystal molecules in the liquid crystal element LC to change with time. For example, when the optical axis directions of the liquid crystal molecules in the liquid crystal element LC are substantially disordered and interlaced with each other, the three-dimensional image beam 60 passing through the light diffusion element 430 will be scattered by the liquid crystal molecules. In other words, when the controller 432 controls the arrangement state of the liquid crystal molecules in the liquid crystal element LC to be in a chaotic state, the light diffusing element 430 can be in a fogging state and can be used to change the diffusion angle of the three-dimensional image beam 60. On the other hand, when the controller 432 controls the optical axis directions of the liquid crystal molecules in the liquid crystal element LC to be substantially the same, the diffusion angle of the three-dimensional image light beam 60 passing through the light diffusion element 430 will not be changed. In other words, the light diffusion element 430 at this time can be in a transparent state.

In this way, when the controller 432 controls the arrangement state of the liquid crystal molecules in the liquid crystal element LC to change in time sequence, the diffusion angle of the three-dimensional image light beam 60 passing through the light diffusion element 430 also changes in time sequence accordingly. In this way, the display device 400 can still adjust the uniformity of the overall three-dimensional image beam 60 through the configuration of the light diffusion element 430. Therefore, the display device 400 can also achieve similar effects and advantages to the aforementioned display device 300. Further explanation will be given below.

More specifically, the controller 432 can also control the arrangement state of the liquid crystal molecules of the light diffusion element 430 to present a specific arrangement state according to the region where it is located. That is, the controller 432 can control the light diffusion element 430 to form a plurality of diffusion patterns. In addition, the controller 432 can also control the diffusion patterns to be correspondingly formed in different timings, and the arrangement state of the liquid crystal molecules when the light diffusion element 430 forms one of the diffusion patterns is the same as that when the light diffusion element 430 forms the other diffusion pattern. The arrangement states of the liquid crystal molecules are different from each other.

More specifically, in this embodiment, the controller 432 can control a diffusion pattern switching frequency of the light diffusion element 430. The diffusion pattern switching frequency is the frequency formed by multiple diffusion patterns per unit time, and when the multiple diffusion patterns When the type of is N, the switching frequency range is greater than N times of 60 Hz. In this way, the controller 432 can adjust the uniformity of the overall three-dimensional image light beam 60 by controlling the type of diffusion pattern of the light diffusion element 430 and the switching frequency of the diffusion pattern, and the display device 400 can also achieve the aforementioned The similar effects and advantages of the display device 300 will not be repeated here.

In summary, the display device of the embodiment of the present invention can adjust the overall uniformity of the three-dimensional image beam through the configuration of the light diffusion element. Therefore, the three-dimensional image beam formed by the light diffusion element has good uniformity. In this way, the display device can provide a three-dimensional image showing uniform brightness, thereby improving the image quality and the user's visual perception.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention. Anyone with ordinary knowledge in the technical field can make some changes and modifications without departing from the spirit and scope of the present invention. The scope of protection of the present invention shall be determined by the scope of the attached patent application.

50: Coherent beam

60: 3D image beam

100, 300, 400: display device

110: Coherent light source

120: display unit

130, 430: light diffusion element

131: Actuator

140: optical components

432: Controller

CM: Concave mirror

IS: Intermediate imaging surface

LC: liquid crystal element

ML: lens

WS: Windshield

FIG. 1 is a schematic structural diagram of a display device according to an embodiment of the invention. 2A is a front view of an image provided by a conventional display device according to a comparative example. FIG. 2B is a front view of an image provided by the display device according to FIG. 1. FIG. FIG. 3 is a schematic structural diagram of a display device according to another embodiment of the invention. 4 is a schematic structural diagram of a display device according to another embodiment of the invention.

50: Coherent beam

60: 3D image beam

100: display device

110: Coherent light source

120: display unit

130: light diffusion element

131: Actuator

140: optical components

CM: Concave mirror

IS: Intermediate imaging surface

ML: lens

WS: Windshield

Claims (3)

A display device includes: a co-tuned light source to provide a co-tuned beam; a display unit that forms a three-dimensional image beam based on the interference of the co-tuned beam, and the three-dimensional image beam is imaged on the display unit after passing through the display unit An intermediate imaging surface; a light diffusion element, arranged on the intermediate imaging surface, wherein the three-dimensional image light beam passes through the light diffusion element to sequentially change the diffusion angle of the three-dimensional image light beam, and the light The diffusion element is a liquid crystal element, and the light diffusion element includes a controller that controls the arrangement state of the liquid crystal molecules in the liquid crystal element to change with time; and at least one optical element located in the light source On the transmission path of the three-dimensional image beam of the diffusion element, the three-dimensional image beam passing through the display unit is projected out of the display device to display a three-dimensional image. The display device according to claim 1, wherein the controller is capable of controlling the light diffusion element to form a plurality of diffusion patterns, each of the diffusion patterns is correspondingly formed in different timings, and the light diffusion element is formed The arrangement state of the liquid crystal molecules in one of the diffusion patterns is different from the arrangement state of the liquid crystal molecules when the light diffusion element forms the other diffusion pattern. The display device according to claim 2, wherein the controller is capable of controlling a diffusion pattern switching frequency of the light diffusion element, and the diffusion pattern switching frequency is a frequency at which the plurality of diffusion patterns are formed per unit time, And when the multiple When there are N types of diffusion patterns, the range of the switching frequency is greater than N times of 60 Hz.

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