WO2023058432A1

WO2023058432A1 - Display device

Info

Publication number: WO2023058432A1
Application number: PCT/JP2022/034649
Authority: WO
Inventors: 美木子中西; 幹生岩村; 康夫森永
Original assignee: 株式会社Ｎｔｔドコモ
Priority date: 2021-10-08
Filing date: 2022-09-15
Publication date: 2023-04-13

Abstract

The purpose of the invention is to suppress blurring of an image when the image is generated by scanning image light.　A display device 1 comprises a reflecting member 10 having a reflecting surface 10a that reflects image light relating to an image, and an image light-emitting device 20 including an image light-emitting unit that is positioned and arranged with respect to the reflecting surface 10a and scans and emits image light while changing the emission direction with respect to the reflecting surface 10a, and a control unit 24 that performs control according to the emission direction of the image light to change the focal position of the image light emitted from the image light-emitting unit so that the image light reflected by the reflecting surface 10a becomes parallel light.

Description

Display device

The present invention relates to display devices.

Conventionally, there has been known a scanning display device equipped with a MEMS (Micro Electro Mechanical Systems) scanner that scans image light to generate an image. A scanning display device is used, for example, in a vehicle head-up display (see, for example, Patent Document 1).

JP 2015-169691 A

The scanning display device described above can also be used as a display device worn on the user's eyes, for example, as a spectacles-type display device. For example, the scanned image light is reflected by a reflecting member such as a hologram or a concave mirror in front of the user's eyes and projected onto the user's eyes, thereby allowing the user to recognize the image. It is desirable that the image light reflected by the reflecting member and projected on the user should be parallel light. The image light that is not parallel light is seen by the user as a blurred portion with degraded resolution.

In the display device worn on the user's eye, it is difficult to place the image light emitting device that emits image light at a fixed distance from all positions on the reflecting surface of the reflecting member. For example, the image light emitting device is arranged at a position where the image light is obliquely incident on the reflecting surface of the reflecting member. In such an arrangement, if the image light is uniformly emitted from the image light emitting device, some of the reflected image light will not be parallel light. Therefore, part of the image recognized by the user is blurred.

An embodiment of the present invention has been made in view of the above, and an object thereof is to provide a display device capable of suppressing blurring of an image when an image is generated by scanning image light.

In order to achieve the above object, a display device according to an embodiment of the present invention provides a reflective member having a reflective surface that reflects image light relating to an image; An image light emitting portion that scans and emits image light while changing the emitting direction with respect to the reflecting surface, and an image light emitting portion that emits the image light after being reflected by the reflecting surface according to the emitting direction of the image light so that the image light becomes parallel light. and a control unit that performs control to change the focal position of the image light emitted from the image light emitting unit.

In the display device according to one embodiment of the present invention, the image light reflected by the reflecting member becomes parallel light under the control of the control unit regardless of the position where the reflecting member reflects. Therefore, according to the display device according to the embodiment of the present invention, it is possible to suppress the blurring of the image when the image is generated by scanning the image light.

According to one embodiment of the present invention, it is possible to suppress image blurring when an image is generated by scanning image light.

1 is a diagram schematically showing the configuration of a display device according to an embodiment of the invention; FIG. It is a figure showing image light when control concerning an embodiment is not performed.

Hereinafter, embodiments of the display device according to the present invention will be described in detail along with the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and overlapping descriptions are omitted. Also, the dimensional ratios in the drawings do not necessarily match those in the description.

FIG. 1 schematically shows the configuration of a display device 1 according to this embodiment. As shown in FIG. 1 , the display device 1 includes a reflective member 10 and an image light emitting device 20 . In the display device 1, the image light emitting device 20 scans and emits image light (rays) relating to an image (video) to be displayed. That is, the display device 1 is a scanning display device. FIG. 1 shows image light beams A and B, which are part of image light beams to be scanned. The emitted image light is reflected by the reflecting member 10 and projected toward the eye (pupil) E of the user. The user perceives the image when the image light is incident on the user's pupil.

For example, the display device 1 is a display device such as a spectacles-type display device that is worn on the user's eyes. The reflecting member 10 is generally plate-shaped like a lens of spectacles, and is provided in a portion corresponding to the lens. The display device 1 may be provided with two reflecting members 10 corresponding to both eyes of the user. The display device 1 includes a frame that holds the reflecting member 10 in front of the user's eyes as a mechanism for wearing the user's eyes, like ordinary spectacles. The image light emitting device 20 is fixed, for example, at a temple of the frame at a position where the image light can be emitted to the reflecting member 10 as described above. The display device 1 may be provided with two image light emitting devices 20 respectively corresponding to the two reflecting members 10 .

A material that transmits light may be used as the reflecting member 10 . In this case, the user can visually recognize the external space together with the image displayed on the display device 1 . That is, the display device 1 may be see-through glasses (smart glasses).

The display device 1 does not have to be worn on the user's eyes, and the positional relationship between the reflecting member 10 and the image light emitting device 20 that scans and emits image light is fixed. Anything that can be arranged is acceptable. The reflecting member 10 and the image light emitting device 20 that scans and emits image light may or may not be connected to each other as in the case where the frame is used.

The reflecting member 10 is a member having a reflecting surface 10a that reflects image light. The reflective surface 10 a of the reflective member 10 has an area capable of reflecting the image light scanned and emitted by the image light emitting device 20 . As the reflecting member 10, for example, a conventional hologram, concave mirror, or the like can be used.

The image light emitting device 20 is an image light emitting unit that scans and emits image light relating to an image to be displayed. The image light emitting device 20 is positioned and arranged with respect to the reflecting surface 10 a of the reflecting member 10 . The image light emitting device 20 scans and emits image light onto the reflecting surface 10a while changing the emission direction (emission angle, deflection angle). For example, the image light emitting device 20 emits image light (rays) corresponding to each pixel forming an image in an emission direction corresponding to each pixel. The image light emitting device 20 scans and emits the image light, thereby allowing the user to recognize the image.

The image light emitting device 20 acquires information related to an image to be displayed and emits image light according to the acquired information. The image light emitting device 20 has a communication function, and may acquire information related to the image to be displayed from another device (not shown) connected by wire or wirelessly. Alternatively, the image light emitting device 20 may acquire information related to an image to be displayed that is stored in advance by itself.

The image light emitting device 20 can be configured using an image light emitting device (MEMS scanner) used for conventional MEMS (Micro Electro Mechanical Systems) scan displays. Note that the image light emitting device 20 may be any device other than the above as long as it scans and emits image light relating to an image to be displayed.

The image light emission device 20 may be provided at a position where the direction of the center of the range of emission directions of the image light differs from the direction of the front of the reflecting surface. For example, as shown in FIG. 1, the image light emitting device 20 may be provided so as to emit image light obliquely rather than from the front of the reflecting surface 10a. As described above, when the display device 1 is worn on the user's eyes, it is difficult to install the image light emitting device 20 in front of the reflecting surface 10a due to the configuration of the display device 1. is.

In this embodiment, the focal position of each image light emitted from the image light emitting device 20 is controlled (adjusted) so that the image light reflected by the reflecting surface 10a becomes parallel light as shown in FIG. adjusted. Since the image light reflected by the reflecting surface 10a becomes parallel light, it is possible to suppress blurring of an image when an image is generated by scanning the image light.

Here, we will explain the problems that occur when the above control is not performed. The distance from the output position of the image light of the image light output device 20 to the reflecting surface 10a varies depending on the output direction of the image light. For example, the distance from the output position of the image light A shown in FIG. When the distances are different in this manner, the focal position of the image light is uniform, that is, when the distance from the emission position of the image light to the focal position of the image light is constant, all the image light reflected by the reflecting surface 10a is collimated. Light and incapable. For example, as shown in FIG. 2, the reflected image light A can be parallel light, but the reflected image light B cannot be parallel light. In an image formed by image light, a portion formed by image light that is not parallel light appears blurred to the user.

In particular, as shown in FIG. 2, when the image light is emitted obliquely from the reflecting surface 10a, the difference in distance between the emission directions of the image light becomes large, and the blurring of the image may become conspicuous. The above control according to the present embodiment is for suppressing blurring of an image when an image is generated by scanning image light.

As shown in FIG. 1, the image light emitting device 20 includes a light source 21, a plurality of

lenses

22a, 22b, and 22c, a micromirror 23, and a controller 24. In addition to the above, the image light emitting device 20 also has a function normally possessed by an image light emitting device (for example, a function of acquiring information related to an image to be displayed). The light source 21 , the plurality of

lenses

22 a , 22 b , 22 c and the micromirror 23 constitute an image light emitting section of the image light emitting device 20 .

The light source 21 is a device that generates and emits image light. The light source 21 is, for example, an LED (Light Emitting Diode) or a laser light source. That is, the image light may be LED light or laser light. The light source 21 is positioned and fixed within the image light emitting device 20 . The generation and emission of the image light by the light source 21 may be performed in the same manner as the image light emission device provided in the conventional scanning display device.

The plurality of

lenses

22a, 22b, and 22c are optical elements used for emitting image light and arranged in the traveling direction of the image light. A plurality of

lenses

22a, 22b, and 22c are used to control the focal position of the image light. As shown in FIG. 2 , a plurality of

lenses

22 a , 22 b , 22 c are arranged in order on the optical path of the image light emitted from the light source 21 . As a mechanism including the

lenses

22a, 22b and 22c, a conventional zoom lens mechanism used for controlling the focal position of light can be used.

Among the plurality of

lenses

22a, 22b, and 22c, the lens 22b provided in the middle is provided so as to be movable in the optical path direction (back and forth) of the image light, and is the focal point of the image light emitted from the image light emission device 20. The position can be changed. The

other lenses

22 a and 22 c are positioned and fixed within the image light emitting device 20 . The image light emitting device 20 has a mechanism for moving the lens 22b, and the lens 22b is moved under the control of the controller 24. FIG. A conventional mechanism may be used for moving the lens 22b.

Note that the number of the plurality of

lenses

22a, 22b, and 22c does not have to be three as described above, and may be any number. Also, the lens that is moved to control the focal position of the image light does not have to be the lens 22b provided in the middle, and any specific lens may be used. Further, the optical elements used for controlling the focal position of the image light need not be the

lenses

22a, 22b, and 22c, and may be optical elements other than the lenses.

The micromirror 23 is a member for changing the emission direction of the image light, that is, for scanning the image light. The micromirror 23 is provided on the optical path of the image light emitted from the lens 22c. The micromirror 23 reflects the image light emitted from the lens 22 c as the image light emitted from the image light emitting device 20 . The micromirror 23 is provided so that the angle of the reflecting surface can be changed. The angle of the reflecting surface of the micromirror 23 is controlled so that the image light is emitted from the image light emission device 20 in the emission direction according to the position of the image light in the image. Control of the angle of the micromirror 23 may be performed in the same manner as in the conventional scanning display device. As the micromirror 23, a micromirror used in a conventional scanning display device can be used.

The control unit 24 adjusts the focal position of the image light emitted from the image light emitting device 20 according to the emission direction of the image light so that the image light reflected by the reflecting surface 10a of the reflecting member 10 becomes parallel light. This is the functional unit that controls the change. For example, the control unit 24 may include a mechanism (for example, an electronic board for control or a small computer) for controlling an optical system related to emission of image light, which is also provided in a conventional scanning display device. It can be realized by providing a function.

The control unit 24 moves the lens 22b back and forth to change the focal position of the image light emitted from the image light emitting device 20. The control unit 24 stores in advance the position of the lens 22b for each emission direction of the image light, and moves the position of the lens 22b based on the storage. That is, the controller 24 moves the position of the lens 22b in synchronization with the movement of the micromirror 23. FIG. The movement of the lens 22b for each emission direction of the image light is for adjusting the focal position of the image light to a position where the image light after being reflected by the reflecting surface 10a of the reflecting member 10 becomes parallel light as described above. is. For example, when the image light is emitted in a direction in which the distance from the image light emission position in the image light emission device 20 to the reflection surface 10a of the reflection member 10 is short, that is, when the optical path of the image light is shortened. , the control unit 24 moves the lens 22b away from the light source 21 . Note that the above-described relationship between the emission direction of the image light and the movement direction of the lens 22b is an example, and depending on the conditions (for example, the lens used), the reflected image light becomes parallel light due to a relationship other than the above. The lens 22b may be moved as shown.

As described above, the positional relationship between the reflecting surface 10a of the reflecting member 10 and the output position of the image light in the image light output device 20 is fixed. Therefore, based on the optical characteristics of the reflecting surface 10a, it is calculated in advance which position should be the focal position so that the image light after reflection becomes parallel light for each emission direction of the image light. can do. Control by the control unit 24 may be performed based on the pre-calculation.

Note that the control by the control unit 24 may be performed so that the reflected image light becomes parallel light. Therefore, the image light after the actual reflection does not necessarily have to be strictly parallel light, and it is sufficient if the image light after the actual reflection is close to the parallel light.

Further, the control unit 24 may perform not only control of the focus position of the image light, but also control to correct aberrations such as astigmatism and chromatic aberration of the image light. The control may be performed in the same manner as conventional control for correcting aberration. The above is the configuration of the display device 1 .

In the display device 1 according to the present embodiment, the image light is emitted so that the image light reflected by the reflecting surface 10a of the reflecting member 10 becomes parallel light according to the emission direction of the image light under the control of the control unit 24. The focal position of the image light emitted from the device 20 is changed. Therefore, the image light reflected by the reflecting member 10 becomes parallel light regardless of the position of reflection on the reflecting surface 10a of the reflecting member 10 . Therefore, according to this embodiment, it is possible to suppress blurring of an image when an image is generated by scanning with image light. As a result, for example, it is possible to increase the resolution (improve the quality) of the image of the see-through glass using the MEMS scan display.

Further, as in the above-described embodiment, the control for changing the focal position of the image light is performed by a plurality of lenses, such as the

lenses

22a, 22b, and 22c, which are used to emit the image light and are arranged in the traveling direction of the image light. It may be performed using an optical element. Also, a plurality of optical elements may be arranged between the light source 21 and the micromirror 23 in the optical path of the image light. According to this configuration, control for changing the focus position of the image light can be reliably and easily performed, and the display device 1 can be realized reliably and easily. Moreover, by adopting such a configuration, it is possible to reduce the size of the image light emitting device 20 . However, the configuration for realizing the control to change the focus position of the image light does not necessarily have to be the one described above, and may be other than that.

Further, as in the above-described embodiment, the image light emitting device 20 (image light emitting unit) is arranged such that the direction of the center of the range of the emitting direction of the image light is different from the direction of the front of the reflecting surface 10a of the reflecting member 10. may be provided in That is, the image light emitting device 20 may be provided at a position where the image light is emitted in an oblique direction with respect to the reflecting surface 10a of the reflecting member 10 . As described above, if the display device 1 is worn on the user's eyes, the configuration as described above may be unavoidable. Even in such a case, blurring of the image can be reliably suppressed. However, the arrangement position of the image light emitting device 20 with respect to the reflecting surface 10a of the reflecting member 10 is not limited to the above, and may be any position as long as an image can be formed by the image light.

It should be noted that the block diagrams used in the description of the above embodiments show blocks for each function. These functional blocks (components) are realized by any combination of at least one of hardware and software. Also, the method of implementing each functional block is not particularly limited. That is, each functional block may be implemented using one device that is physically or logically coupled, or directly or indirectly using two or more devices that are physically or logically separated (e.g. , wired, wireless, etc.) and may be implemented using these multiple devices. A functional block may be implemented by combining software in the one device or the plurality of devices.

Functions include judging, determining, determining, calculating, calculating, processing, deriving, investigating, searching, checking, receiving, transmitting, outputting, accessing, resolving, selecting, choosing, establishing, comparing, assuming, expecting, assuming, Broadcasting, notifying, communicating, forwarding, configuring, reconfiguring, allocating, mapping, assigning, etc. can't For example, a functional block (component) responsible for transmission is called a transmitting unit or transmitter. In either case, as described above, the implementation method is not particularly limited.

The order of the processing procedures, sequences, flowcharts, etc. of each aspect/embodiment described in the present disclosure may be changed as long as there is no contradiction. For example, the methods described in this disclosure present elements of the various steps using a sample order, and are not limited to the specific order presented.

Input/output information may be stored in a specific location (for example, memory) or managed using a management table. Input/output information and the like can be overwritten, updated, or appended. The output information and the like may be deleted. The entered information and the like may be transmitted to another device.

The determination may be made by a value represented by one bit (0 or 1), by a true/false value (Boolean: true or false), or by numerical comparison (for example, a predetermined value).

Each aspect/embodiment described in the present disclosure may be used alone, may be used in combination, or may be used by switching along with execution. In addition, the notification of predetermined information (for example, notification of “being X”) is not limited to being performed explicitly, but may be performed implicitly (for example, not notifying the predetermined information). good too.

Although the present disclosure has been described in detail above, it is clear to those skilled in the art that the present disclosure is not limited to the embodiments described in the present disclosure. The present disclosure can be practiced with modifications and variations without departing from the spirit and scope of the present disclosure as defined by the claims. Accordingly, the description of the present disclosure is for illustrative purposes and is not meant to be limiting in any way.

Software, whether referred to as software, firmware, middleware, microcode, hardware description language or otherwise, includes instructions, instruction sets, code, code segments, program code, programs, subprograms, and software modules. , applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, and the like.

In addition, software, instructions, information, etc. may be transmitted and received via a transmission medium. For example, the software uses at least one of wired technology (coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), etc.) and wireless technology (infrared, microwave, etc.) to website, Wired and/or wireless technologies are included within the definition of transmission medium when sent from a server or other remote source.

In addition, the information, parameters, etc. described in the present disclosure may be expressed using absolute values, may be expressed using relative values from a predetermined value, or may be expressed using other corresponding information. may be represented.

The terms "determining" and "determining" used in this disclosure may encompass a wide variety of actions. "Judgement" and "determination" are, for example, judging, calculating, computing, processing, deriving, investigating, looking up, searching, inquiring (eg, lookup in a table, database, or other data structure), ascertaining as "judged" or "determined", and the like. Also, "judgment" and "determination" are used for receiving (e.g., receiving information), transmitting (e.g., transmitting information), input, output, access (accessing) (for example, accessing data in memory) may include deeming that a "judgment" or "decision" has been made. In addition, "judgment" and "decision" are considered to be "judgment" and "decision" by resolving, selecting, choosing, establishing, comparing, etc. can contain. In other words, "judgment" and "decision" may include considering that some action is "judgment" and "decision". Also, "judgment (decision)" may be read as "assuming", "expecting", "considering", or the like.

The terms "connected", "coupled", or any variation thereof, mean any direct or indirect connection or coupling between two or more elements, It can include the presence of one or more intermediate elements between two elements being "connected" or "coupled." Couplings or connections between elements may be physical, logical, or a combination thereof. For example, "connection" may be read as "access". As used in this disclosure, two elements are defined using at least one of one or more wires, cables, and printed electrical connections and, as some non-limiting and non-exhaustive examples, in the radio frequency domain. , electromagnetic energy having wavelengths in the microwave and optical (both visible and invisible) regions, and the like.

The term "based on" as used in this disclosure does not mean "based only on" unless otherwise specified. In other words, the phrase "based on" means both "based only on" and "based at least on."

Any reference to elements using the "first," "second," etc. designations used in this disclosure does not generally limit the quantity or order of those elements. These designations may be used in this disclosure as a convenient method of distinguishing between two or more elements. Thus, reference to a first and second element does not imply that only two elements can be employed or that the first element must precede the second element in any way.

Where "include," "including," and variations thereof are used in this disclosure, these terms are inclusive, as is the term "comprising." is intended. Furthermore, the term "or" as used in this disclosure is not intended to be an exclusive OR.

In this disclosure, if articles are added by translation, such as a, an, and the in English, the disclosure may include that the nouns following these articles are plural.

In the present disclosure, the term "A and B are different" may mean "A and B are different from each other." The term may also mean that "A and B are different from C". Terms such as "separate," "coupled," etc. may also be interpreted in the same manner as "different."

1... display device, 10... reflective member, 10a... reflective surface, 20... image light emitting device, 21... light source, 22a, 22b, 22c... lens, 23... micromirror, 24... control unit.

Claims

a reflective member having a reflective surface that reflects image light relating to an image;
an image light emitting unit that is positioned and arranged with respect to the reflecting surface and that scans and emits the image light while changing the emitting direction with respect to the reflecting surface;
a control unit that performs control to change the focal position of the image light emitted from the image light emitting unit so that the image light after being reflected by the reflecting surface becomes parallel light according to the emission direction of the image light;
A display device.
The image light emitting unit includes a plurality of optical elements used for emitting image light and arranged in the traveling direction of the image light,
2. The display device according to claim 1, wherein the control unit performs control to change the focal position of the image light by moving one of the plurality of optical elements in the traveling direction of the image light.
The image light emitting unit further includes a light source for emitting image light and a micromirror for scanning the image light emitted from the light source,
3. The display device according to claim 2, wherein the plurality of optical elements are arranged between the light source and the micromirror in an optical path of image light.
The display device according to any one of claims 1 to 3, wherein the image light emitting portion is provided at a position where the direction of the center of the range of the emitting direction is different from the direction of the front of the reflecting surface.