CN115993717A

CN115993717A - Directional backlight display device with eye tracking function

Info

Publication number: CN115993717A
Application number: CN202111211588.1A
Authority: CN
Inventors: 陈锡勳
Original assignee: E Lead Electronic Co Ltd
Current assignee: E Lead Electronic Co Ltd
Priority date: 2021-10-18
Filing date: 2021-10-18
Publication date: 2023-04-21

Abstract

The invention provides a directional backlight display device with an eye tracking function, which comprises a light source module, a reflective narrow-angle diffusion sheet, a backlight display panel, an eye tracking module and a tracking operation control module. A reflective narrow angle diffuser has a rotation axis, and reflects light and forms a uniform directional light beam. The backlight type infrared image signal display panel is arranged on a projection light path of the uniform light directional light beam, and the uniform light directional light beam projects an image displayed by the backlight type display panel to a projection area. The tracking operation control module receives position information from the eye tracking module and forms an eye coordinate, calculates a corresponding correction projection area when the eye coordinate deviates, and controls a driving module to drive the reflective narrow-angle diffusion sheet to rotate along the rotating shaft, so that the angle of the light projected to the reflective narrow-angle diffusion sheet by the light source module is changed, and the light-equalizing directional light beam moves towards the correction projection area to achieve the effect of tracking eyes.

Description

Directional backlight display device with eye tracking function

Technical Field

The present invention relates to a directional backlight display device, and more particularly, to a directional backlight display device capable of tracking the position of eyes.

Background

As shown in fig. 1, in the previous invention of the applicant, the reflective narrow angle diffusion sheet 2 is provided with an array of a plurality of micro curved surface mirrors 21, and the array is arranged in a square shape or a hexagonal honeycomb shape, each micro curved surface mirror 21 has a size of 2.5 um-0.25 mm, the micro curved surface mirrors 21 can be micro concave mirrors or micro convex mirrors, and the reflective narrow angle diffusion sheet 2 can be a plane or a curved surface. Each micro-curved mirror 21 may have the same or different curvatures and angles.

The number of micro-curved mirrors 21 on the reflective narrow angle diffuser 2 can be tailored to the resolution and optical path design requirements.

As shown in fig. 2A, the plane mirror has a flat and smooth surface, and the incident angle of the incident light is equal to the reflection angle of the reflected light, so that the diffusion angle of the light beam is maintained unchanged, the diffusion effect is not generated, and the viewing angle is limited.

As shown in fig. 2B, in order for viewers at all angles to see the image on the projector planar screen, a wide surface scattering is required to diffuse the light projected on the plane in all directions, but at the same time, the brightness of the image is greatly reduced.

As shown in fig. 2C and 2D, the micro-curved mirror of the reflective narrow-angle diffusion sheet can diffuse the incident light toward a predetermined direction at a predetermined and narrow diffusion angle α1, so that the brightness of the viewing image can be greatly improved within the predetermined direction and the diffusion angle α1. Wherein the reflecting surface of the micro-curved mirror can be concave or convex.

Disclosure of Invention

As shown in fig. 3, in another previous invention of the applicant, the micro-curved mirror 21 array of the reflective narrow angle diffusion sheet 2 has the characteristic of diffusing light toward a set direction and a narrow angle, and when the light L of the light source module 1 is projected onto the reflective narrow angle diffusion sheet 2, a uniform directional light beam D generated by the light reflected from the reflective narrow angle diffusion sheet 2 penetrates a backlight display panel 3 (e.g. a liquid crystal panel) to form a uniform directional image light beam DI, and is projected and diffused to an area (eye box E).

The light-equalizing directional image beam of fig. 3 has a small spread angle and concentrated brightness, and can provide extremely high display brightness by adopting a low-power light source, but because the eye box is very small, the eyes of the viewer can exceed the original eye box and cannot see the image as long as the viewer moves the body or swings the head, or replaces different viewers.

The invention provides a directional backlight display device with an eye tracking function, which tracks eyes of an observer by moving positions of eye boxes, so that the observer can see complete images when the observer is positioned at different positions. As shown in fig. 4A, the cross-sectional area of the light-equalizing directional light beam D is larger than that of the backlight display panel 3, and when the backlight display panel 3 is fixed and the angle of the reflective narrow-angle diffusion sheet 2 is rotated, the direction of the light-equalizing directional light beam D can be changed, so that the light-equalizing directional image light beam DI generated by penetrating the backlight display panel 3 is projected in different directions. As shown in fig. 4B, when the reflective narrow angle diffusion sheet 2 is rotated upward by θ1 degrees, the light-uniformizing directional light beam D is also rotated upward by θ10 degrees, and θ10 is approximately equal to θ1×2. As shown in fig. 4C, when the reflective narrow angle diffusion sheet 2 is rotated by θ2 degrees toward the lower side, the light-uniformizing directional light beam D is also rotated by θ20 degrees toward the lower side, and θ20 is approximately equal to θ2×2; the angle of projection of the image I can be changed by only irradiating the light-equalizing directional beam D to the whole area of the backlight display panel 3 displaying the image I within the rotating angle range, so as to achieve the effect of moving the position of the eye box.

As shown in fig. 5, when the reflective narrow angle diffusion sheet 2 is rotated to move the position of the eye box, and the reflective narrow angle diffusion sheet 2 is rotated upward, downward, leftward and rightward, the light-equalizing directional light beam D is also rotated upward, downward, leftward and rightward, respectively, and the position of the eye box E is moved in the corresponding direction.

The invention provides a directional backlight display device with eye tracking function, comprising:

a light source module for projecting a light;

the reflective narrow-angle diffusion sheet is provided with an array of which a rotating shaft is controlled by a driving module and a plurality of micro-curved mirrors, and reflects the light and uniformly projects the light at a narrow diffusion angle to form a uniform light directional light beam;

a backlight display panel disposed on the projection path of the uniform directional light beam, the backlight display panel displaying an image, the uniform directional light beam penetrating the backlight display panel to project the image to a projection area (i.e. eye box);

an eye tracking module for detecting the position of an eye of the viewer;

and the tracking operation control module receives position information from the eye tracking module and forms an eye coordinate, when the eye coordinate deviates from the center of the projection area and the deviation value is larger than a set threshold value, the tracking operation control module calculates a correction projection area corresponding to the deviated eye coordinate and controls the driving module to drive the reflective narrow-angle diffusion sheet to rotate by taking the rotating shaft as the axis so as to change the angle of the light source module projected to the reflective narrow-angle diffusion sheet and enable the uniform-light directional light beam to move towards the correction projection area.

The eye tracking module can also detect the position of eyes of the viewer, the tracking operation control module calculates an intermediate coordinate of the eyes according to the position of the eyes, and when the intermediate coordinate deviates from the center of the projection area and the deviation value is larger than a set threshold value, the tracking operation control module calculates the correction projection area according to the deviated intermediate coordinate.

The reflective narrow-angle diffusion sheet and the driving module are arranged on a base, the base is provided with a second rotating shaft and is controlled by a second driving module, and the second driving module drives the reflective narrow-angle diffusion sheet to rotate by taking the second rotating shaft as an axis.

The reflective narrow-angle diffusion sheet can also rotate along the rotating shaft and the second rotating shaft at the same time.

The projection light path of the uniform-light directional image light beam comprises a windshield, the virtual image and the front scenery watched by the viewer are fused together, and the viewer can see the virtual image and the front scenery at the same time.

The projection light path of the uniform-light directional image light beam comprises a concave mirror, and the concave mirror is arranged between the windshield and the backlight display panel and is used for amplifying the size of a virtual image and lengthening the distance of the virtual image.

The driving module and the reflective narrow angle diffusion sheet are driven by gears, the reflective narrow angle diffusion sheet is provided with an input gear, and the driving module is provided with an output gear; the output gear and the input gear may be parallel axis gears, intersecting axis gears, or intersecting axis gears.

The driving module and the reflective narrow angle diffusion sheet are in flexible transmission, the reflective narrow angle diffusion sheet is provided with an input belt wheel, and the driving module is provided with an output belt wheel; the flexible driving element used by the output belt wheel and the input belt wheel can be a belt, a rope or a chain.

The second driving module and the base are driven by gears, the base is provided with a second input gear, and the second driving module is provided with a second output gear; the second output gear and the second input gear may be parallel axis gears, intersecting axis gears, or staggered axis gears.

The second driving module and the base are in flexible transmission, the base is provided with a second input belt wheel, and the second driving module is provided with a second output belt wheel; the flexible driving element used by the second output belt wheel and the second input belt wheel can be a belt, a rope or a chain.

The transmission mode of the driving module driving the reflective narrow-angle diffusion sheet and the second driving module driving the base can be the same or different.

The eye tracking module is provided with an infrared light source and two infrared cameras, the infrared light source projects infrared rays to the viewer, the two infrared cameras capture the infrared rays reflected by the viewer to form two infrared image signals to the tracking operation control module, and the tracking operation control module forms the eye coordinates through an image identification and position coordinate algorithm.

The eye tracking module may also have an infrared light source, an infrared camera and a distance sensor, the infrared light source projects an infrared ray to the viewer, the infrared camera captures the infrared ray reflected by the viewer to form an infrared image signal to the tracking operation control module, the distance sensor obtains a distance signal of the distance between the head of the viewer and the distance sensor to the tracking operation control module, and the tracking operation control module forms the eye coordinates through an image identification and position coordinate algorithm.

Drawings

Fig. 1 is a schematic view of a disclosed reflective narrow angle diffuser.

Fig. 2A, 2B, 2C, and 2D are schematic diffusion diagrams of projection light on different reflection surfaces.

Fig. 3 is a schematic diagram of a directional backlight display device applied by the applicant.

Fig. 4A, fig. 4B, and fig. 4C are schematic diagrams of a light beam and a backlight display panel after reflection and diffusion by the reflective narrow angle diffusion sheet.

Fig. 5 is a schematic view of the movement of an ophthalmic lens rotating a reflective narrow angle diffuser.

Fig. 6 is a schematic view of the first embodiment.

Fig. 7A, 7B, and 7C are schematic diagrams of monocular tracking according to the first embodiment.

Fig. 8A, 8B, and 8C are schematic diagrams of binocular tracking according to the first embodiment.

Fig. 9 is a schematic diagram of a second embodiment.

Fig. 10 is a schematic view of a third embodiment.

Fig. 11 is a schematic view of a fourth embodiment.

Fig. 12A to 12J are schematic views of gear transmission.

Fig. 13A, 13B, 13C, and 13D are schematic views of a single shaft embodiment of a gear transmission.

Fig. 14A, 14B, 14C are schematic views of a geared dual spindle embodiment.

Fig. 15A, 15B, 15C are schematic views of a flexible drive embodiment.

Fig. 16A and 16B are schematic diagrams of an eye tracking module.

Fig. 17A and 17B are schematic diagrams illustrating the position detection calculation of eye movement.

Fig. 18A, 18B, and 18C are schematic diagrams of eye movement position detection calculation and reflective narrow angle diffuser rotation.

Fig. 19 is another schematic diagram of an eye tracking module.

Fig. 20A, 20B, and 20C are schematic views of the longitudinal tracking of the eye box.

Reference numerals illustrate:

2: reflective narrow angle diffuser

3: backlight type display panel

D: uniform light directional beam

DI: uniform light directive image light beam

E: eye box

Alpha, alpha 1: diffusion angle

1: light source module

2: reflective narrow angle diffuser

21: micro-curved mirror

22: rotating shaft

23: input gear

B23: input belt wheel

And B230: second input pulley

And (B): flexible driving member

FB2: second flexible transmission part

3: backlight type display panel

4: driving module

41: motor with a motor housing

42: reduction gear set

43: output gear

B43: output belt wheel

B430: second output belt pulley

40: second driving module

401: second motor

402: second reduction gear set

403: second output gear

5: eye tracking module

51: infrared light source

52. 521, 522: infrared camera

53: distance sensor

6: tracking operation control module

61: position information

62: eye coordinates

7: windshield glass

8: concave mirror

9: base seat

91: frame

92: second rotating shaft

93: second input gear

CLP: center shaft

CL, CL1, CL2: center line

D: uniform light directional beam

DI: uniform light directive image light beam

E: eyes (eyes)

ER: right eye

E2: two eyes

I: image processing apparatus

L: light ray

P: viewers and viewers

RL: infrared ray

T: target object

VI: virtual image

Z: eye box

SL, SR, SD, SU, dc, dcc, dcch, dccv, dp: distance of

STH, STV: displacement threshold value

θ1, θ10, θ2, θ20, Δθfl, Δθpl, Δθfr, Δθpr, Δθf, Δθp, θp1, θp2, θc11, θc12, θc21θc22, θc, Δψpu, Δψfu, Δψpd, Δψfd, ψc: angle of

Detailed Description

As shown in fig. 6, a directional backlight display device with eye tracking function includes a light source module 1 for projecting light L, a reflective narrow angle diffuser 2, a backlight display panel 3, a driving module 4, an eye tracking module 5, and a tracking operation control module 6.

The reflective narrow angle diffusion sheet 2 is provided with a rotating shaft 22 and an input gear 23, the reflective surface of the reflective narrow angle diffusion sheet 2 is provided with an array formed by a plurality of micro-curved mirrors 21, and the reflective narrow angle diffusion sheet 2 reflects light rays L and uniformly projects the light rays L at a narrow diffusion angle to form a uniform light directional light beam D;

the backlight type display panel 3 is disposed on a projection light path of the light-equalizing directional light beam D (i.e., in a projection direction of the light-equalizing directional light beam D), the backlight type display panel 3 displays an image I, the light-equalizing directional light beam D penetrates the backlight type display panel 3 and illuminates the image I to form the light-equalizing directional image light beam DI, and the light-equalizing directional image light beam DI is projected to a projection area (i.e., an eye box Z of the viewer P);

the driving module 4 is provided with a motor 41 and a reduction gear set 42, the motor 41 is connected to the reduction gear set 42, an output gear 43 of the reduction gear set 42 is meshed with the input gear 23 of the reflective narrow angle diffusion sheet 2, and the motor 41 drives the output gear 43 through the reduction gear set 42 to drive the reflective narrow angle diffusion sheet 2 to rotate around the rotating shaft 22;

the eye tracking module 5 has an infrared light source 51, an infrared camera 52 and a distance sensor 53, wherein the infrared light source 51 projects infrared rays RL to the viewer P, the infrared camera 52 captures the infrared rays RL reflected by the viewer P to form an infrared image signal, and the distance sensor 53 obtains a distance signal between the head of the viewer and the distance sensor 53.

The tracking control module 6 has an operation processor, an algorithm and a motor control circuit, and the eye tracking module 5 outputs the infrared light image signal and the distance signal to the tracking control module 6 as position information 61 of the eyes E of the viewer P, and the tracking control module 6 generates the eye coordinates 62 of the eyes E of the viewer P by an algorithm of image recognition and position coordinates. When the eye coordinates 62 deviate from the center coordinates of the eye box Z and the deviation value is greater than a set threshold value, the tracking operation control module 6 calculates an angle required to rotate when the projection area is moved to a corrected projection area (i.e., the current position of the eye), the current position of the reflective narrow angle diffusion sheet 2 is taken as a reference, and controls the driving module 4 to drive the reflective narrow angle diffusion sheet 2 to rotate, so as to change the incident angle of the light L of the light source module 1 projected to the reflective narrow angle diffusion sheet 2, and enable the light-equalizing directional light beam D to turn and the projection area (eye box Z) of the light-equalizing directional image light beam DI to move towards the corrected projection area, thereby achieving the effect of tracking the eye. The set threshold value can avoid driving the reflective narrow angle diffusion sheet 2 excessively frequently, reduce the system operation load and motor noise, and rotate the reflective narrow angle diffusion sheet to adjust the projection area only when the position of the eyes E of the viewer P is greatly changed and the projection area (i.e., the eye box Z of the viewer P) is about to be separated.

In another embodiment, the eye tracking module 5 may have an infrared light source 51 and two infrared cameras 52, the infrared light source 51 projects infrared rays RL to the viewer P, the two infrared cameras 52 capture the infrared rays RL reflected by the viewer P to form two infrared image signals, the eye tracking module 5 outputs the infrared image signals to the tracking control module 6 as the position information 61 of the eyes E of the viewer P, and the tracking control module 6 generates the eye coordinates 62 of the eyes E of the viewer P by an image recognition and position coordinate algorithm.

As shown in fig. 7A, the range of the eye box Z covers only the right eye ER, the light-equalizing directional light beam formed by reflection of the reflection type narrow angle diffusion sheet 2 penetrates the backlight type display panel 3 to become the light-equalizing directional image light beam DI, and the center of the projection area (the eye box Z) is at the right eye ER of the viewer P. As shown in fig. 7B, when the right eye ER of the viewer P is detected to move a distance SL to the left of the viewer, and the distance SL is greater than a horizontal displacement threshold STH, for example, 2 cm, the driving module 4 rotates the reflective narrow angle diffusion sheet 2 by an angle Δθfl to the left of the viewer, so that the light-equalizing directional image light beam DI passing through the backlight display panel 3 is rotated by an angle Δθpl to the left of the viewer, and the center of the eye box Z is moved to the right eye ER of the viewer P. As shown in fig. 7C, if the right eye ER of the viewer P is detected to move a distance SR to the right of the viewer, and the distance SR is greater than the horizontal displacement threshold STH, the driving module 4 rotates the reflective narrow-angle diffusion sheet 2 by an angle Δθfr to the right of the viewer, and rotates the light-homogenizing directional image light beam DI passing through the backlight display panel 3 by an angle Δθpr to the right of the viewer, so that the center of the eye box Z moves to the right eye ER of the viewer P. Thus, the position change of the right eye ER of the viewer P is continuously detected and tracked to adjust the projection position of the eye box Z, so that the image watched by the viewer P is not interrupted.

As shown in fig. 8A, if the projection area (eye box Z) covers both eyes E2, the center of the projection area (eye box Z) of the light-equalizing directional image light beam DI is in the middle of both eyes E2 of the viewer P. As shown in fig. 8B, when the distance SL of the left eye E2 of the viewer P is detected and is greater than a horizontal displacement threshold STH, for example, 3 cm, the driving module 4 rotates the reflective narrow angle diffusion sheet 2 by an angle Δθfl toward the left of the viewer, so that the light-equalizing directional image light beam DI passing through the backlight display panel 3 rotates by an angle Δθpl toward the left of the viewer, and the center of the projection area is maintained in the middle (i.e. the middle coordinates) of the left eye E2 of the viewer P. As shown in fig. 8C, if the distance SR that the right eye ER of the viewer P moves to the right of the viewer is detected, and the distance SR is greater than the horizontal displacement threshold value STH, the driving module 4 rotates the reflective narrow-angle diffusion sheet 2 by an angle Δθfr to the right of the viewer P, and rotates the light-homogenizing directional image light beam DI passing through the backlight display panel 3 by an angle Δθpr to the right of the viewer, so as to maintain the center of the projection area in the middle (i.e. middle coordinates) of the eyes E2 of the viewer P. Thus, the position change of the eyes E2 of the viewer P is continuously detected and tracked to adjust the projection position of the eye box Z, so that the image watched by the viewer P is not interrupted.

As shown in fig. 9, the second embodiment further includes a base 9 and a second driving module 40, wherein the reflective narrow-angle diffuser 2 and the driving module 4 are mounted on the base 9, the base 9 has a second rotating shaft 92 and a second input gear 93, the second driving module 40 has a second motor 401 and a second reduction gear set 402, the second motor 401 is connected to the second reduction gear set 402, a second output gear 403 of the second reduction gear set 402 is meshed with the second input gear 93 of the base 9, and the second motor 401 drives the second output gear 403 to drive the base 9 to rotate around the second rotating shaft 92 through the second reduction gear set 402.

When the reflective narrow angle diffusion sheet 2 rotates around the rotation shaft 22, the reflective narrow angle diffusion sheet 2 may also rotate around the second rotation shaft 92.

As shown in fig. 10, in the third embodiment, the projection light path of the backlight display panel 3 further includes a windshield 7, which is located between the viewer P and the backlight display panel 3, and projects the virtual image VI to the viewing direction of the viewer P, so that the viewer P can see the virtual image VI and the front scene at the same time.

As shown in fig. 11, the projection light path of the backlight display panel 3 further includes a concave mirror 8 between the windshield 7 and the backlight display panel 3, so that the uniform directional image light beam DI projected by the backlight display panel 3 is reflected by the concave mirror 8 and the windshield 7, and the concave mirror 8 is used for enlarging the size of the virtual image VI and lengthening the distance of the virtual image VI.

In the above embodiment, the output gear, the input gear, the second output gear, and the second input gear may be parallel shaft gears, such as spur gears (fig. 12A), helical gears (fig. 12B), racks (fig. 12C), helical racks (fig. 12D), internal gears (fig. 12E), helical internal gears (fig. 12F), intersecting shaft gears, such as straight bevel gears (fig. 12G), helical bevel gears (fig. 12H), or intersecting shaft gears, such as intersecting shaft helical gears (fig. 12I), and worm gears (fig. 12J).

As shown in fig. 13A, the reflective narrow angle diffusion sheet 2 may have a rotating shaft 22 in a horizontal direction, wherein the output gear 43 is a spur gear, the input gear 23 is a spur gear on the rotating shaft 22, and the motor 41 drives the spur gear on the rotating shaft 22 through the reduction gear set 42 to rotate the reflective narrow angle diffusion sheet 2 in the horizontal direction.

As shown in fig. 13B, the output gear 43 is a worm, the input gear 23 is a worm wheel on the rotating shaft 22, and the motor 41 drives the worm wheel on the rotating shaft 22 through the reduction gear set 42 to rotate the reflective narrow angle diffusion sheet 2 in the horizontal direction.

As shown in fig. 13C, the reflective narrow angle diffusion sheet 2 may have a vertical rotation shaft 22, wherein the output gear 43 is a spur gear, the input gear 23 is an internal curved rack on the reflective narrow angle diffusion sheet 2, and the motor 41 drives the spur gear through the reduction gear set 42 to drive the internal curved rack to rotate the reflective narrow angle diffusion sheet 2 in the vertical direction.

As shown in fig. 13D, the output gear 43 is a worm, the input gear 23 is a worm wheel on the rotating shaft 22, and the motor 41 drives the worm wheel on the rotating shaft 22 through the reduction gear set 42 to rotate the reflective narrow angle diffusion sheet 2 in the vertical direction.

As shown in fig. 14A, the reflective narrow angle diffusion sheet 2 may also have both horizontal and vertical rotation axes, in which the output gear 43 is a worm, the input gear 23 is a worm wheel on a vertical rotation axis, and the motor 41 drives the worm wheel on the vertical rotation axis through the reduction gear set 42 to rotate the reflective narrow angle diffusion sheet 2 in the vertical direction. The second output gear 403 is a spur gear, the second input gear 93 is a spur gear located on the horizontal rotation axis of the base 9, and the second motor 401 drives the spur gear via the second reduction gear set 402 to drive the spur gear on the horizontal rotation axis of the base 9, and rotates the reflective narrow angle diffusion plate 2 in the horizontal direction.

As shown in fig. 14B, the output gear 43 is a worm, the input gear 23 is a worm wheel on a vertical rotation axis, and the motor 41 drives the worm wheel on the vertical rotation axis through the reduction gear set 42 to rotate the reflective narrow angle diffusion sheet 2 in the vertical direction. The second output gear 403 is a straight-tooth conical gear, the second input gear 93 is a straight-tooth conical gear located on the horizontal rotation axis of the base 9, and the second motor 401 drives the straight-tooth conical gear through the second reduction gear set 402 to drive the straight-tooth conical gear on the horizontal rotation axis of the base 9 to rotate the reflective narrow-angle diffusion sheet 2 in the horizontal direction.

As shown in fig. 14C, there may be provided a motor 41 and a second motor 401 for driving a bevel gear as an output gear 43 and a second output gear 403, the two bevel gears being engaged with each other, the two

motors

41, 401 being located on the same axis, the motor 41 driving the output gear 43 on the axis through a reduction gear set 42, the second motor 401 driving the frame 91 through a second reduction gear set 402, the second output gear 403 being provided on the frame 91, the second output gear 403 being rotatable on the frame 91, the second output gear 403 being interlocked with the reflective narrow angle diffusion sheet 2. When the motor 41 rotates and the second motor 401 does not rotate, the frame 91 is fixed, and the motor 41 drives the output gear 43 through the reduction gear set 42 to drive the second output gear 403 and the reflective narrow angle diffusion sheet 2 to rotate in the horizontal direction. When the motor 41 and the second motor 401 are rotated in the same direction at the same speed, there is no relative rotation between the output gear 43 and the second output gear 403, and the frame 91 rotates in the vertical direction with the reflective narrow angle diffusion sheet 2. When the motor 41 and the second motor 401 rotate at different speeds, there is a relative rotation between the output gear 43 and the second output gear 403, and the second output gear 403 rotates in the horizontal direction with the reflective narrow angle diffusion sheet 2, and the frame 91 rotates in the vertical direction with the reflective narrow angle diffusion sheet 2.

The output gear, the input gear, the second output gear, and the second input gear in the above embodiments may be replaced by pulleys and flexible driving members, and the flexible driving members may be belts, ropes, or chains.

As shown in fig. 15A, the reflective narrow angle diffusion sheet 2 may have a rotation axis in a horizontal direction, the output pulley B43 of the driving module 4 is coupled with the input pulley B23 of the reflective narrow angle diffusion sheet 2 by means of a flexible transmission FB, the motor 41 drives the output pulley B43 through the reduction gear set 42, and drives the input pulley B23 by means of the flexible transmission FB to drive the reflective narrow angle diffusion sheet 2 to rotate in the horizontal direction.

As shown in fig. 15B, the reflective narrow angle diffusion sheet 2 may have a vertical rotation axis, the output pulley B43 of the driving module 4 is coupled with the input pulley B23 of the reflective narrow angle diffusion sheet 2 by means of a flexible transmission FB, the motor 41 drives the output pulley B43 through the reduction gear set 42, and drives the input pulley B23 by means of the flexible transmission FB to drive the reflective narrow angle diffusion sheet 2 to rotate in the vertical direction.

As shown in fig. 15C, the reflective narrow angle diffusion sheet 2 may also have a rotation axis in both horizontal and vertical directions, the output pulley B43 of the driving module 4 is coupled to the input pulley B23 of the reflective narrow angle diffusion sheet 2 by means of the flexible transmission FB, the motor 41 drives the output pulley B43 through the reduction gear set 42, and drives the input pulley B23 to drive the reflective narrow angle diffusion sheet 2 to rotate in the vertical direction by means of the flexible transmission FB. The second output pulley B430 of the second driving module 401 is coupled to the second input pulley B230 of the base 9 by means of the second flexible transmission FB2, the second motor 401 drives the second output pulley B430 through the second reduction gear set 402, and drives the second input pulley B230 by means of the second flexible transmission FB2 to drive the reflective narrow angle diffusion sheet 2 to rotate in the horizontal direction.

As shown in fig. 16A, the eye tracking module 5 may be an infrared light source 51 and two horizontally spaced

infrared cameras

521 and 522, which are spaced apart from each other by a distance DCC. As shown in fig. 16B, the image of each ir camera is defined by a conical coordinate system, so that the horizontal angle thetac between the target T and the center line CL of the ir camera or the vertical angle ψc between the target T and the center line CL of the ir camera can be known, and the distance between the target T and the ir camera can not be known.

As shown in fig. 17A, by two infrared cameras 521, 555 with known horizontal distances Dcc, the horizontal angles θc11, θc21 between the center lines of the two infrared cameras and the right eye of the viewer can be measured, and the longitudinal distance Dc between the right eye of the viewer and the infrared camera can be calculated by trigonometric function formula:

as shown in fig. 17B, when the distance SL of the viewer's right eye moving to the left, the horizontal angles θc12 and θc22 between the two infrared camera centerlines CL1 and CL2 and the viewer's right eye are measured, and the distance SL of the viewer's right eye moving at present can be calculated by trigonometric function formula:

as shown in fig. 18A, the vertical distance between the

infrared cameras

521 and 522 and the backlight display panel 3 is known as a, so that the vertical distance Dp between the right eye of the viewer and the backlight display panel can be estimated:

D _p ＝D _c +a

as shown in fig. 18B, the initial central axis CLP of the backlight display panel 3 forms a horizontal angle θp1 with the image light projected to the right eye of the viewer, and when the right eye of the viewer moves a distance SL to the left, the horizontal angle θp2 required by the image light projected to the right eye of the viewer can be calculated by matching the longitudinal distance Dp between the right eye of the viewer and the backlight display panel:

as shown in fig. 18C, the angle Δθp by which the image light projected from the backlight display panel 3 needs to be deflected can be calculated:

Δθ _p ＝θ _p2 -θ _p1

according to the optical lever principle of the reflection law, when the incident light is unchanged and the mirror surface rotates by an angle alpha, the angle of the reflected light is changed to be 2 alpha, so that the horizontal angle delta theta f of the reflective narrow-angle diffusion sheet required to rotate can be obtained:

one of the infrared cameras of the eye tracking module 5 may be changed to a distance sensor, which may detect the distance of the head of the viewer by using infrared, ultrasonic or millimeter waves. The tracking operation control module obtains an infrared image signal and a distance signal, and calculates the position coordinates of eyes of the viewer at the moment by using an image identification and position coordinate algorithm to obtain the horizontal angle of the reflective narrow-angle diffusion sheet required to rotate.

In order to detect the precise movement amount in the horizontal direction, the two infrared cameras 521,522 of the eye tracking module may be disposed horizontally at a distance Dcch and vertically at a distance Dccv as shown in fig. 19.

Therefore, the movement amount of eyes in the horizontal and vertical directions can be detected, the rotation angle of the reflective narrow-angle diffusion sheet in the horizontal and vertical directions at the moment is calculated, the driving module is controlled to rotate the angle of the reflective narrow-angle diffusion sheet, the center of the eye box is maintained in eyes of an observer, and the image watched by the observer is not interrupted.

As shown in fig. 20A, for example, the uniform light directional light beam reflected and diffused by the reflective narrow angle diffusion sheet 2 passes through the backlight type display panel 3, and then becomes a uniform light directional image light beam DI, and the center of the projected eye box Z is positioned on the right eye ER of the viewer P.

As shown in fig. 20B, when the downward movement distance SD of the right eye ER of the viewer is detected and is greater than a vertical displacement threshold STV, for example 1 cm, the driving module rotates the reflective narrow-angle diffusion sheet downward by an angle Δψfd, so that the light-homogenizing directional image beam passing through the backlight display panel 3 rotates downward by an angle Δψpd, and the center of the eye box Z is maintained at the right eye ER of the viewer P.

As shown in fig. 20C, when the distance SU is detected that the right eye ER of the viewer moves upward, and the distance SU is greater than the vertical displacement threshold STV, the driving module rotates the reflective narrow-angle diffusion sheet upward by an angle Δψfu, so that the light-homogenizing directional image beam passing through the backlight display panel 3 rotates upward by an angle Δψpu, and the center of the eye box Z is maintained at the right eye ER of the viewer P.

The eye position change of the observer is continuously detected and tracked to adjust the projection position of the eye box, so that the eye box is amplified to different positions, and the image watched by the observer is not interrupted.

Claims

1. A directional backlight display device having an eye tracking function, comprising:

a light source module for projecting a light;

a backlight display panel disposed on the projection light path of the reflective narrow angle diffusion sheet, wherein the backlight display panel displays an image, and the uniform directional light beam penetrates through the backlight display panel to form a uniform directional image light beam to be projected to a projection area;

an eye tracking module;

and the tracking operation control module receives position information from the eye tracking module and forms an eye coordinate, when the eye coordinate deviates from the center of the projection area, the tracking operation control module calculates a correction projection area according to the deviated eye coordinate and controls the driving module to drive the reflective narrow-angle diffusion sheet to rotate by taking the rotating shaft as the axis so as to change the angle of the light source module projected to the reflective narrow-angle diffusion sheet and enable the uniform-light directional image light beam to be projected on the correction projection area.

2. The device of claim 1, wherein the eye tracking module detects a binocular position, the tracking operation control module calculates an intermediate coordinate of the eye coordinates according to the binocular position, and the tracking operation control module calculates the corrected projection area according to the deviated intermediate coordinate when the intermediate coordinate deviates from the center of the projection area.

3. The device of claim 1, wherein the tracking control module calculates the corrected projection area according to the deviated eye coordinates when the eye coordinates deviate from the center of the projection area and the deviation is greater than a predetermined threshold.

4. The device of claim 1, wherein the reflective narrow angle diffuser and the driving module are mounted on a base having a second axis of rotation and controlled by a second driving module.

5. The device of claim 4, wherein the reflective narrow angle diffuser rotates along the axis and the second axis simultaneously.

6. The device of claim 1, wherein the projection path of the uniform directional image beam comprises a windshield.

7. The device of claim 6, wherein the projection path of the uniform directional image beam comprises a concave mirror disposed on the path between the windshield and the backlight display panel.

8. The device of claim 1, wherein the reflective narrow angle diffuser has an input gear engaged with an output gear set of the driving module.

9. The directional backlight display device with eye tracking as defined in claim 1, wherein the reflective narrow angle diffuser has an input pulley, and the driving module drives the input pulley through an output pulley and a flexible transmission member.

10. The device of claim 4, wherein the base has a second input gear engaged with a second output gear set of the second driving module.

11. The device of claim 4, wherein the base has a second input pulley, and the second driving module drives the second input pulley through a second output pulley and a second flexible transmission member.

12. The directional backlight display device with eye tracking as defined in claim 1, wherein the position information comprises two infrared image signals.

13. The directional backlight display device with eye tracking as defined in claim 1, wherein the position information comprises an infrared image signal and a distance signal.