WO2012133379A1 - Head-mounted display and method for adjusting brightness thereof - Google Patents

Abstract

A head-mounted display provided with display units (15,16) for displaying an image, a switching unit (6) for switching between a display state for displaying an image on the display units (15, 16) and a non-display state for not displaying an image on the display units (15, 16), brightness adjusting units (13, 14) for adjusting the brightness of the image displayed on the display units (15, 16), and an external light detector (5) for detecting the amount of external light. When the non-display state is switched to the display state by the switching unit (6), the brightness adjusting units (13, 14) adjusts the amount by which brightness is changed per unit of time in order to increase the brightness of the image from the brightness of the display units (15, 16) in the non-display state to the brightness of the image displayed on the display units (15, 16) in the display state, the adjustment being made in accordance with the amount of external light detected by the external light detector (5).

Description

Head mounted display and its brightness adjustment method

The present disclosure relates to a head mounted display that is characterized by switching between a display state in which video is displayed and a non-display state in which video is not displayed.

Patent Document 1 discloses a see-through type head mounted display (hereinafter referred to as HMD). The user can visually recognize an external scenery through the lens unit while viewing the image projected through the lens unit.

JP 2006-267887 A

When the user operates the switching unit, the display device switches from a non-display state in which no video is projected to a display state in which the video is projected. When an image is displayed on the display device, the image is projected onto the lens unit and appears in front of the user's eyes. When the video is displayed, the user's eyes undergo a rapid change in luminance. As a result, the user may not be able to accurately view the video until the user gets used to the brightness of the video. For example, when the user is in a dark place, the user's eyes have become accustomed to the darkness, so that the situation becomes more prominent. Further, when the switching unit is operated, the display device is switched from the display state to the non-display state. When the image disappears, the image disappears suddenly from the front. Thereby, the video displayed on the user's eyes remains as an afterimage, and the user may not be able to visually recognize the video accurately.

This disclosure is intended to provide a head mounted display that allows a user to accurately view a video regarding video display when switching between a non-display state and a display state.

One aspect of the present disclosure switches between a display unit that is mounted in front of a user's eyes and displays an image, a display state in which the display unit displays an image, and a non-display state in which the display unit does not display an image. A switching unit; a luminance adjusting unit that adjusts the luminance of an image displayed by the display unit; and an external light detecting unit that detects an external light amount. The luminance adjusting unit is in the non-display state by the switching unit. And, when switching from one of the display states to the other, to increase or decrease the luminance of the video from the luminance of the display unit in the non-display state to the luminance of the video displayed by the display unit in the display state This is an HMD that adjusts the amount of change in luminance per hour according to the external light amount detected by the external light detection unit.

According to this, when the switching unit is switched from one of the non-display state and the display state to the other, the luminance adjustment unit is configured to display the video displayed on the display unit according to the external light amount detected by the external light detection unit. Adjusts the amount of change in luminance that changes in luminance over time. By adjusting the amount of change in luminance according to the amount of external light, the user can accurately view the video when the switching unit switches from one of the non-display state and the display state to the other. Furthermore, it is possible to quickly change the brightness of the image in the display state. Furthermore, it is possible to quickly change the brightness to the non-display state.

In addition, when the switching unit is switched from the non-display state to the display state by the switching unit, the luminance adjustment unit is configured to display an image displayed by the display unit in the display state based on the luminance of the display unit in the non-display state. You may provide the increase adjustment part which adjusts the brightness | luminance change amount which changes per hour for increasing the brightness | luminance of an image | video to a brightness | luminance according to the said external light amount detected by the said external light detection part.

According to this, when the switching unit is switched from the non-display state to the display state, the luminance adjustment unit determines that the luminance of the video displayed on the display unit per unit time depends on the external light amount detected by the external light detection unit. Adjust the amount of change in brightness. By adjusting the amount of change in brightness according to the amount of external light, when the switching unit switches from the non-display state to the display state, the user can accurately view the image and also the brightness of the image in the display state. It can be changed quickly.

In addition, when the switching unit is switched from the display state to the non-display state by the switching unit, the brightness adjustment unit is configured to calculate the display unit in the non-display state from the luminance of the video displayed by the display unit in the display state. A reduction adjustment unit that adjusts a luminance change amount that changes per unit time to reduce the luminance of the video in accordance with the external light amount detected by the external light detection unit may be provided.

According to this, when the switching unit switches from the display state to the non-display state, the luminance adjustment unit causes the luminance of the video displayed on the display unit to be per unit time according to the external light amount detected by the external light detection unit. Adjust the amount of change in brightness. By adjusting the amount of change in brightness according to the amount of external light, when the switching unit switches from the non-display state to the display state, the image displayed on the user's eyes is reduced as an afterimage, and the user Can be accurately recognized, and can be quickly changed to the luminance in the non-display state.

The HMD includes a determination unit that determines whether or not the external light amount detected by the external light detection unit is greater than a predetermined value, and the luminance adjustment unit includes the external light amount detected by the determination unit. When it is determined that the brightness change amount is greater than the predetermined value, the brightness change amount is adjusted to a first value, and when the determination unit determines that the detected external light amount is equal to or less than the predetermined value, the brightness change amount is determined. You may adjust to the 2nd value smaller than the said 1st value.

According to this, when the determination unit determines that the external light amount is larger than the predetermined value, the luminance adjustment unit sets the luminance change amount as the first value, and the determination unit determines that the external light amount is equal to or less than the predetermined value. The brightness change amount is set to a second value smaller than the first value. Thereby, when the surroundings of the user are bright, the contrast between the light amount of the image incident on the user's eyes and the ambient external light amount is small. For this reason, the luminance change amount is relatively large, that is, the video is displayed relatively quickly. Further, when the surroundings of the user are dark, the contrast between the light amount of the image and the ambient light amount is large. For this reason, the amount of change in luminance is relatively small, that is, a video is displayed relatively slowly. Accordingly, it is possible to perform video display that allows the user to accurately recognize the external light amount.

The HMD may include a half mirror that is disposed in front of the user's eyes and reflects the image projected from the display unit to guide the eyes.

According to this, the HMD is equipped with a half mirror. In a situation where the image in front of the eyes and the surrounding scenery can be seen at the same time, switching the images instantaneously tends to adversely affect the eyes of the user. That is, by adjusting the luminance change amount of the transmissive head mounted display, it is possible to further reduce the adverse effects on the user's eyes compared to the immersive head mounted display.

In addition, the HMD includes a mounting detection unit that detects whether or not a user has mounted the head mounted display, and the brightness adjustment unit is configured to switch the switching when the mounting detection unit detects mounting of the head mounted display. When the display unit is switched between the display state and the non-display state by the unit, the luminance change amount is adjusted, and when the mounting detection unit does not detect mounting of the head mounted display, the switching unit displays the display When the state is switched between the non-display state and the non-display state, the luminance change amount may not be adjusted.

According to this, it is equipped with the mounting | wearing detection part which detects whether the user mounted | wore the head mounted display. Thereby, it is possible to adjust the luminance change amount only when the user wears the head mounted display. That is, the luminance change amount is adjusted only in an appropriate situation where it is necessary to adjust the luminance change amount. Conversely, in a situation where the user does not wear a head-mounted display, it is not necessary to perform a complicated process of adjusting the luminance change amount, and the luminance adjustment process can be simplified.

Further, the display unit includes a light modulation unit that forms a spatial modulation pattern corresponding to the video, and a display control unit that draws a video on the light modulation unit, and the luminance adjustment unit includes the light modulation A light source that illuminates light from the back of the unit, and a light source control unit that adjusts the amount of light of the light source, and the light source control unit adjusts the amount of light of the light source to adjust the image displayed on the light modulation unit The brightness change amount may be adjusted.

According to this, the HMD includes a light source control unit. Therefore, the luminance change amount of the image can be easily adjusted only by adjusting the light amount of the light source by the light source control unit.

Another aspect of the present disclosure is a luminance adjustment method for adjusting the luminance of an image displayed by a display unit provided in a head-mounted display that is worn in front of a user's eyes, wherein the display unit displays an image. A switching step for switching between a state and a non-display state in which the display unit does not display an image, an external light detection step for detecting an external light amount, and an adjustment step for adjusting the luminance of the video displayed by the display unit; And the adjustment step includes an image displayed by the display unit in the display state from a luminance of the display unit in the non-display state when the non-display state is switched to the display state in the switching step. The brightness change amount that changes per time for increasing the brightness of the video up to the brightness of the image is detected by the outside light detection step. An increase adjustment step that adjusts according to the amount of light, and when the display step is switched from the display state to the non-display state in the switching step, from the luminance of the video displayed by the display unit in the display state, in the non-display state A brightness adjustment step of adjusting a brightness change amount that changes per unit time to reduce the brightness of the video to the brightness of the display unit according to the outside light amount detected in the outside light detection step; Is the method.

According to this, when the switching step is switched between the display state and the non-display state, the adjustment step determines the luminance of the video displayed on the display unit according to the external light amount detected by the external light detection step. Adjust the amount of luminance change that changes per hour. By adjusting the amount of change in brightness according to the amount of external light, the user can accurately view the video even when the video is displayed instantaneously, and can quickly change the brightness of the video in the display state. Can do. In addition, even if the image is erased instantaneously, the image displayed on the user's eyes is reduced from remaining as an afterimage, preventing the user from feeling uncomfortable, and quickly changing to a non-display luminance. Can be made.

The external view which shows the whole structure of HMD1. The block diagram which shows the electric constitution of HMD1. The flowchart which shows the internal process of CPU10 at the time of a video shifting from a non-display state to a display state, or from a display state to a non-display state. Explanatory drawing which shows a mode that the brightness | luminance of an image | video changes when an image | video transfers from a non-display state to a display state or from a display state to a non-display state.

As shown in FIG. 1, the HMD 1 includes a head mounting portion 2 and a frame 3. The user can also visually recognize the outside world while visually recognizing the image projected on the half mirror 4. That is, the HMD 1 is a see-through HMD.

The head mounting unit 2 is a device that projects image light in front of the user H's eyes. The video light is generated by converting a video signal transmitted through a cable (not shown) by a video generation unit described later. The head mounting unit 2 includes a half mirror 4, an external light detection unit 5, a switching unit 6, a mounting detection unit 7, and a video input unit 8.

The video input unit 8 receives a video signal via a cable (not shown). The video signal is, for example, in the High Definition Multimedia Interface (HDMI: registered trademark) format. The video input unit 8 is an HDMI terminal, for example.

The half mirror 4 is a mirror on which the image light emitted from the image generation unit is projected. The user can visually recognize the image light projected on the half mirror 4 through the half mirror 4 while visually recognizing the scenery of the outside world. The half mirror 4 is made of, for example, a plate material such as glass or transparent resin on which a metal thin film is formed so that the transmittance becomes a predetermined ratio (for example, 50%).

External light detection unit 5 detects external light in front of the user's eyes. The external light detection unit 5 is, for example, an illuminance sensor that outputs a detection signal corresponding to the illuminance in front of the eyes.

The switching unit 6 is configured to be operable by the user. By the operation of the switching unit 6, the display state in which the image light is projected onto the half mirror 4 is switched to the non-display state in which the image light is not projected onto the half mirror 4. The switching unit 6 switches from a non-display state in which the image light is not projected onto the half mirror 4 to a display state in which the image light is projected onto the half mirror 4. The switching unit 6 has, for example, a configuration that switches between a display state and a non-display state by pressing a button.

The wearing detection unit 7 detects whether or not the HMD 1 is worn on the user's head H. The attachment detection unit 7 is a distance sensor, for example. The attachment detection unit 7 includes an infrared LED and an infrared sensor. The infrared LED emits infrared light. The infrared sensor detects infrared light reflected by the user's head.

The frame 3 supports the head mounting part 2. The frame 3 is formed so that the user's eyes and the half mirror 4 face each other when the head mounting portion 3 is mounted on the user's head H. The frame 3 has a frame shape of eyeglasses, for example.

As shown in FIG. 2, the video signal is input to the video generation unit 10 via the video input unit 8. The video generation unit 10 emits video light based on the video signal. The video generation unit 10 includes a CPU 17, a ROM 11, a RAM 12, a light source control unit 13, a light source 14, a display control unit 15, a light modulation unit 16, and a system bus 18. The CPU 17 constitutes a computer together with the ROM 11 and the RAM 12. The system bus 18 includes an external light detection unit 5, a switching unit 6, a mounting detection unit 7, a video input unit 8, a CPU 17, a ROM 11, a RAM 12, a light source control unit 13, a display control unit 15, Connected to each.

The ROM 11 stores a program for realizing processing according to a flowchart described later. The program is executed by the CPU 17 using the RAM 12. The ROM 11 stores at least set luminance BDmax, minimum luminance BDmin, predetermined light amounts L1, L2, L3, L4, L5, and L6, and predetermined luminance change amounts A1, A2, A3, A4, A5, and A6.

The RAM 12 functions as a temporary storage area for storing various variables to be referred to when the CPU 17 executes a program stored in the ROM 11. The various variables include at least an external light amount L described later.

The light source control unit 13 is connected to the light source 14. The light source control unit 13 outputs a luminance control signal that gradually increases the amount of light from the light source 14 when the switching unit 6 switches from the non-display state to the display state. Furthermore, the light source control unit 13 also outputs a luminance control signal such that the light amount from the light source 14 gradually decreases when the switching unit 6 switches from the display state to the non-display state.

The light source 14 emits light with a predetermined amount of light according to the luminance control signal output from the light source control unit 13. The light emitted from the light source 14 is modulated into video light by the light modulator 16. The image light condensed by the condenser lens is emitted to the half mirror 4. The light source 14 is, for example, an LED.

The display control unit 15 is connected to the light modulation unit 16. The display control unit 15 receives the video signal output from the video input unit 8 and optically modulates the display control signal so that the video light is displayed based on information such as color and gray scale included in the video signal. To the unit 16.

The light modulator 16 operates so that the light emitted from the light source 14 is modulated based on the display control signal output from the display controller 15. The light modulation unit 16 is, for example, an LCD.

The processing of the CPU 17 is started according to the brightness control program of FIG. Each step shown in the flowchart represents processing of the CPU 17.

When a power button (not shown) is pressed and the power to the HMD 1 is turned on, in step 100, the brightness control program is started.

In step 101, it is determined whether or not the wearing detection unit 7 has detected that the HMD 1 is worn on the head H of the user. If the attachment of the HMD 1 is detected, the process proceeds to step 102. If it is not detected that the HMD 1 is attached, step 101 is repeated.

In step 102, it is determined whether or not the switching unit 6 has switched from the non-display state to the display state. If the switching unit 6 determines that the non-display state has been switched to the display state, the process proceeds to step 103. If it is not determined that the switching unit 6 has switched from the non-display state to the display state, Step 102 is repeated.

In step 103, the external light detection unit 5 is instructed to detect the external light amount L, and the external light amount L detected by the external light detection unit 5 is stored in the RAM 12.

In step 104, it is determined whether or not the external light quantity L is greater than or equal to a predetermined light quantity L1. If the external light quantity L is greater than or equal to the light quantity L1, the process proceeds to step 105. When the external light amount L is smaller than the predetermined light amount L1, the process proceeds to step 106. The predetermined light quantity L1 is stored in the ROM 11 in advance.

In Step 105, as a result of determining that the external light quantity L is greater than or equal to the light quantity L1 in Step 104, the brightness change amount A1 is set as the brightness change amount A. Then, the process proceeds to Step 109. The predetermined brightness change amount A1 is stored in the ROM 11 in advance.

In step 106, it is determined whether or not the external light quantity L is smaller than the predetermined light quantity L1 and the external light quantity L is greater than or equal to the predetermined light quantity L2. If the external light amount L is smaller than the predetermined light amount L1 and the external light amount L is equal to or greater than the predetermined light amount L2, the process proceeds to step 107. When the external light quantity L is smaller than the predetermined light quantity L2, the process proceeds to step 108. The predetermined light quantity L2 is stored in the ROM 11 in advance.

In step 107, when it is determined in step 106 that the external light amount L is smaller than the predetermined light amount L1 and the external light amount L is equal to or greater than the predetermined light amount L2, the luminance change amount A2 is set as the luminance change amount A. . The predetermined brightness change amount A2 is stored in the ROM 11 in advance. The luminance change amount A2 is smaller than the luminance change amount A1. After step 107, the process proceeds to step 109.

In step 108, when it is determined in step 106 that the external light amount L is equal to or greater than the predetermined light amount L1, the luminance change amount A3 is set as the luminance change amount A. The predetermined brightness change amount A3 is stored in the ROM 11 in advance. The luminance change amount A3 is smaller than the luminance change amount A2. After step 108, the process proceeds to step 109.

In step 109, the light source control unit 13 is instructed to set the light amount of the light source 14 to the minimum luminance BDmin. In accordance with this command, the light amount of the light source 14 is set to the minimum luminance BDmin by the light source control unit 13. The minimum luminance BDmin is, for example, 0 cd / m ² and is stored in advance in the ROM 11.

In step 110, the display control unit 15 is instructed to change the video display from the non-display state to the display state. Upon receiving this command, the display control unit 15 controls the light modulation unit 16 based on the video signal input to the video input unit 8 so that the light emitted from the light source 14 becomes video light according to the video signal. To do.

In step 111, the light source control unit 13 is instructed to increase the luminance according to the luminance change amount A. In accordance with this command, the light amount of the light source 14 is gradually increased by the light source controller 13 from the minimum luminance BDmin to the set luminance BDmax. The luminance change amount A is determined so that the change amount A increases as the external light amount L increases. Further, the luminance change amount A is determined according to a time T required to reach a set luminance BD from a minimum luminance BDmin described later. Specifically, the luminance change amount A is determined such that the time T from the minimum luminance BDmin to the set luminance BD is between 0.1 seconds and 1.0 seconds. The set brightness BDmax is, for example, 600 cd / m ² and is stored in advance in the ROM 11.

In step 112, it is determined whether or not the switching unit 6 has switched from the display state to the non-display state. If it is determined that the display state has been switched to the non-display state, the process proceeds to step 113. If it is not determined that the display state is switched to the non-display state, step 112 is repeated.

In step 113, the outside light detection unit 5 is instructed to detect the outside light amount L. The external light amount L detected by the external light detection unit 5 is stored in the RAM 12.

In step 114, it is determined whether or not the external light quantity L is greater than or equal to a predetermined light quantity L3. If the external light quantity L is greater than or equal to the predetermined light quantity L3, the process proceeds to step 115. When the external light quantity L is smaller than the predetermined light quantity L3, the process proceeds to step 116.

In step 115, when it is determined in step 114 that the external light amount L is greater than or equal to the predetermined light amount L3, the luminance change amount A4 is set as the luminance change amount A. Then, the process proceeds to step 115.

In step 116, it is determined whether or not the external light quantity L is smaller than the predetermined light quantity L3 and the external light quantity L is equal to or greater than the predetermined light quantity L4. If the external light quantity L is smaller than the predetermined light quantity L3 and the external light quantity L is greater than or equal to the predetermined light quantity L4, the process proceeds to step 117. When the external light quantity L is smaller than the predetermined light quantity L4, the process proceeds to step 118.

In step 117, when it is determined in step 116 that the external light amount L is smaller than the predetermined light amount L3 and the external light amount L is equal to or greater than the predetermined light amount L4, the luminance change amount A5 is set as the luminance change amount A. . After the processing of step 117, the process proceeds to step 119.

In step 118, when it is determined in step 116 that the external light amount L is smaller than the predetermined light amount L4, the luminance change amount A6 is set as the luminance change amount A. After the process of step 118, the process proceeds to step 119.

In step 119, the light source control unit 13 is instructed to decrease the luminance until the minimum luminance BDmin is reached in accordance with the luminance change amount A. The greater the external light quantity L, the greater the change amount A. In accordance with this command, the light amount of the light source 14 is gradually decreased by the light source control unit 13 until the minimum luminance BDmin is reached. The minimum luminance BDmin is, for example, 0 cd / m ² .

In step 120, the display control unit 15 is instructed to change the video display from the display state to the non-display state. Upon receiving this instruction, the display control unit 15 initializes the light modulation unit 16 based on the video signal input to the video input unit 8.

When a power button (not shown) is pressed and the power to the HMD 1 is cut off, in step 121, the brightness control program ends.

In FIG. 4, the horizontal axis represents time, and the vertical axis represents luminance. The luminance change amount A1 is a value determined such that, for example, the time T1 from the minimum luminance BDmin = 0 cd / m ² to the set luminance BDmax = 600 cd / m ² reaches 0.1 second. The luminance change amount A2 is a value determined such that the time T2 from the minimum luminance BDmin = 0 cd / m ² to the set luminance BDmax = 600 cd / m ² is 0.4 seconds, for example. The luminance change amount A3 is a value determined such that, for example, the time T3 from the minimum luminance BDmin = 0 cd / m ² to the set luminance BDmax = 600 cd / m ² reaches 1.0 second. The luminance change amount A4 is a value determined such that the time T4 from the set luminance BDmax = 600 cd / m ² to the minimum luminance BDmin = 0 cd / m ² is 0.1 second, for example. The luminance change amount A5 is a value determined such that the time T5 from the set luminance BDmax = 600 cd / m ² to the minimum luminance BDmin = 0 cd / m ² is 0.3 seconds, for example. The luminance change amount A6 is a value determined such that the time T6 from the set luminance BDmax = 600 cd / m ² to the minimum luminance BDmin = 0 cd / m ² is 0.8 seconds, for example. Predetermined light amounts L1 and L3, which are threshold values of the external light amount L, are 500 lux. 500 lux corresponds to standard office brightness. Predetermined light amounts L2 and L4 that are threshold values of the external light amount L are 100 lux. 100 lux corresponds to the brightness of the streetlight.

The brightness increasing operation and the brightness decreasing operation executed in accordance with the process of the brightness control program shown in FIG. 3 will be specifically described with reference to FIG. First, in step 100, when the user presses the power button to turn on the power, it is detected in step 101 that the HMD 1 is mounted on the user's head. The user can perform a predetermined operation or the like while viewing the surrounding situation through the half mirror 4 while wearing the HMD 1. The user operates the switching unit 6 when he / she wants to see necessary information such as manual information at an arbitrary time during a predetermined work or when the information is no longer needed. When the switching unit 6 is pressed in a state where the wearing of the HMD 1 is detected, a luminance increasing operation or a luminance decreasing operation is executed.

[Brightness increase operation]
In step 102, the switching unit 6 is pressed to switch from the non-display state to the display state. In step 103, the external light quantity L is detected. At this time, the external light quantity L is assumed to be 300 lux. In step 104, the predetermined light quantity L1 is 500 lux, and the external light quantity L is 300 lux. The external light amount L is smaller than the predetermined light amount L1, and the process proceeds to step 106. In step 106, the predetermined light quantity L2 is 100 lux, and the external light quantity L is 300 lux. It is determined that the external light amount L is smaller than the predetermined light amount L1 and the external light amount L is greater than or equal to the predetermined light amount L2. In step 107, the luminance change amount A2 is set as the predetermined luminance change amount A. In step 109, the minimum luminance is set to 0 lux. In step 110, the non-display state is changed to the display state. As shown in FIG. 4, since the predetermined luminance change amount A2 is set in step 111, the time T2 is 0.4 seconds. Therefore, the luminance is gradually increased so that the set luminance BD is reached 0.4 seconds after the non-display state is changed to the display state.

[Brightness reduction operation]
In step 112, the switching unit 6 is pressed to switch from the display state to the non-display state. In step 113, the external light quantity L is detected. At this time, it is assumed that the external light quantity L is 50 lux. In step 114, the predetermined light quantity L3 is 500 lux, and the external light quantity L is 50 lux. Therefore, the external light amount L is smaller than the predetermined light amount L3, and the process proceeds to step 116. In step 116, the predetermined light quantity L2 is 100 lux, and the external light quantity L is 50 lux. Therefore, the external light amount L is smaller than the predetermined light amount L4, and the process proceeds to step 118. In step 118, the luminance change amount A6 is set as the predetermined luminance change amount A. As shown in FIG. 4, since the predetermined luminance change amount A6 is set in step 119, the time T6 is 1.0 second. For this reason, the luminance is decreased more slowly than the luminance increasing operation so that the minimum luminance 0 lux is reached from the set luminance BD 1.0 seconds after the luminance change amount A6 is set in step 118. In step 120, the display state is changed to the non-display state. In step 121, when the user presses the power button to shut off the power, the brightness control program ends.

〔Example of use〕
The HMD 1 of the present embodiment is used for work support in a factory, for example. An operator usually assembles parts by hand while looking at a manual written in paper. In the manual, assembly process diagrams and precautions for assembly are specified. In this case, the worker must work while moving the line of sight alternately between the manual and the parts. The image displayed on the HMD 1 of the present embodiment is a manual such as a part assembly process diagram and precautions for assembling parts. Thereby, the operator can minimize the movement of the line of sight for viewing the parts and the manual. As a result, the work efficiency of the worker can be improved.

The HMD 1 of this embodiment is used for displaying subtitles in a movie theater, for example. The video displayed on the HMD 1 is, for example, a movie subtitle. As a result, when the audience of the movie theater views the subtitles in a bright situation before the screening, or views the subtitles in a dark situation during the screening, when the audience wants to see the subtitles and presses the switching unit 6, Subtitles can be displayed without causing discomfort.

[Effects of Examples]
The wearing detection unit 7 includes an infrared light source that emits infrared light toward the head, and an infrared detection unit that detects infrared light emitted from the infrared light source and reflected by the head. As a result, it is easy to determine whether or not the user has worn the head on the head, without imposing a complicated operation on the head, as compared with the case where the wearing is detected based on whether or not a button provided on the head mounted display or the like has been pressed. Can be detected.

Time T1 is a value that is 0.1 seconds or longer. If the time T1 is less than 0.1 seconds, the user may feel that the video has been displayed instantaneously in front of the eyes, which may cause discomfort to the user. By setting the time T1 to 0.1 seconds or longer, there is no possibility that the display time is too early and the user is uncomfortable.

Time T3 is a value that is 1.0 second or less. If the time T3 is longer than 1.0 seconds, the user may feel that it takes too much time for the video to completely appear in front of the eyes, which may cause discomfort to the user. By setting the time T3 to 1.0 second or less, there is no possibility that the display time is too late and the user is uncomfortable.

The predetermined light quantity L1 is, for example, 500 lux or less. 500 lux corresponds to a standard office light. When the head mounted display is used in a bright office, the predetermined luminance change amount A1 is used. When the head mounted display is used in a dark office, the predetermined luminance change amount A2 is used. Thereby, the head mounted display suitable for an office use can be provided.

The HMD 1 includes a half mirror 4 that is disposed in front of the user's eyes and reflects the image projected from the light modulation unit 16 to guide the eyes. In a situation where the image in front of the eyes and the surrounding scenery can be seen at the same time, switching the images instantaneously tends to adversely affect the eyes of the user. By adjusting the luminance change amount of the HMD 1 including the half mirror 4, that is, the transmissive head mounted display, the user can view the video more accurately than the immersive head mounted display.

[Modification]
In the present embodiment, the switching unit 6 has a button configuration that can be pressed by the user, but is a means for receiving a switching command transmitted from an external device such as a PC and supplying the switching command to the luminance adjusting unit. It doesn't matter. The switching unit 6 performs a switching operation by a user's manual operation. When the user wears the HMD 1, the switching unit 6 automatically switches from the non-display state to the display state. It may be configured to switch to.

In this embodiment, the minimum luminance BDmin = 0 cd / m ² , but it is not necessary that BDmin = 0 cd / m ² . In order to quickly reach the set brightness BDmax in step 111, for example, the minimum brightness BDmin = 100 cd / m ² may be set.

In the present embodiment, although a set luminance BDmax = 600cd / ^{m 2,} may not be BDmax = 600cd / ^{m 2.} For example, the HMD 1 may be provided with a set brightness adjusting unit, and the set brightness BDmax may be increased or the set brightness BDmax may be decreased by a predetermined operation by the user. Thereby, the user can adjust the luminance of the video display to an appropriate luminance that is easy for the user to visually recognize.

Also, the time T1, T2, and T3 from the minimum brightness BDmin to the set brightness BDmax may be fixed, and the brightness change amounts A1, A2, and A3 may be changed according to the times T1, T2, and T3. Thereby, when the light amount difference from the minimum luminance BDmin to the set luminance BDmax is relatively small, it is possible to prevent the time T1 from becoming extremely short and the user from being able to visually recognize the video accurately. Similarly, when the light amount difference from the minimum luminance BDmin to the set luminance BDmax is relatively large, the time T3 becomes extremely long, and it is possible to prevent the user from feeling uncomfortable such as slow video display.

Similarly, the time T4, T5, T6 from the set brightness BDmax to the minimum brightness BDmin may be fixed, and the brightness change amounts A4, A5, A6 may be changed according to the times T4, T5, T6. Thereby, when the light amount difference from the set luminance BDmax to the minimum luminance BDmin is relatively small, it is possible to prevent the time T4 from becoming extremely short and the user from being able to visually recognize the video accurately. When the light amount difference from the minimum luminance BDmin to the set luminance BDmax is relatively large, it is possible to prevent the user from feeling uncomfortable, for example, the time T6 becomes extremely long and the video is slow to disappear.

In the present embodiment, the luminance change amount A changes linearly, but may change according to various functions. The function is, for example, a function based on human visual characteristics or the like into which parameters such as the amount of external light and the degree of opening of the user's pupil are substituted.

In the present embodiment, the attachment detection unit 7 is an infrared sensor, but a button is provided at the position of the frame where the user's head hits, and when the user's head is attached, the button is pressed to cause the HMD 1 to The structure which detects mounting | wearing to a head may be sufficient.

In this embodiment, the video input unit 8 is an HDMI terminal, but it may be a communication interface such as a LAN or a wireless LAN, an interface such as a DVI terminal, USB, or a memory card reader. The light source 14 is an LED, but may be a laser diode. Although the light modulation unit 16 is an LCD, an organic EL display, a display using a digital mirror device, or a retinal scanning display that allows a worker to visually recognize an image by scanning laser light directly on the worker's eyeball. It may be.

In the present embodiment, three brightness change amounts are set according to the external light amount L: an amount that is greater than or equal to the predetermined light amount L1, an amount that is smaller than the predetermined light amount L1, is greater than or equal to the predetermined light amount L2, and is smaller than the predetermined light amount L2. However, two luminance change amounts may be set. Also, four or more luminance change amounts may be set. Further, the luminance change amount may be changed in direct proportion to the external light amount L. Furthermore, the luminance change amount when the luminance is increased and the luminance change amount when the luminance is decreased may be the same value. Further, the predetermined light amounts L1 and L3 and the predetermined light amounts L2 and L4 are the same value, but may be different values.

[Correspondence with Invention]
The HMD 1 in the present embodiment is an example of a head mounted display in the present invention. The display control unit 15 and the light modulation unit 16 in the present embodiment are examples of the display unit in the present invention. The display control unit 15 and the light modulation unit 16 in this embodiment are examples of the display control unit and the light modulation unit in the present invention in order. The light source control unit 13 and the light source 14 in the present embodiment are an example of a luminance adjustment unit in the present invention. The light source control unit 13 and the light source 14 in this embodiment are an example of a light source control unit and a light source in the present invention in order. The switching unit 6 in the present embodiment is an example of the switching unit in the present invention. The external light detection unit 5 in the present embodiment is an example of an external light detection unit in the present invention. The external light amount L in the present embodiment is an example of the external light amount in the present invention. The predetermined luminance change amounts A1, A2, and A3 in the present embodiment are examples of the luminance change amount in the present invention. The CPU 17 in this embodiment, step 104, step 106, step 114, and step 116 are an example of a determination unit in the present invention. The predetermined light amounts L1 and L2 in the present embodiment are examples of predetermined values in the present invention. When the predetermined light amount L1 in the present embodiment is an example of a predetermined value, the predetermined luminance change amount A1 in the present embodiment is an example of the first value in the present invention, and the predetermined luminance change amount in the present embodiment. A2 and A3 are examples of the second value in the present invention. When the predetermined light quantity L2 in the present embodiment is an example of a predetermined value, the predetermined luminance change amounts A1 and A2 in the present embodiment are examples of the first value in the present invention, and the predetermined luminance in the present embodiment. The change amount A3 is an example of a second value in the present invention. The mounting detection unit 7 in the present embodiment is an example of a mounting detection unit in the present invention. The half mirror 4 in the present embodiment is an example of a half mirror in the present invention. The set brightness BDmax in the present embodiment is an example of the brightness of an image displayed on the display unit in the display state in the present invention. The set brightness BDmin in the present embodiment is an example of the brightness of the display unit in the non-display state in the present invention. Step 103 and step 113 in this embodiment are an example of an external light detection step in the present invention. Step 111 and step 119 in the present embodiment are examples of adjustment steps in the present invention. Step 111 in the present embodiment is an example of an increase adjustment unit and an increase adjustment step in the present invention. Step 119 in this embodiment is an example of a decrease adjustment unit and a decrease adjustment step in the present invention. Step 102 and step 112 in this embodiment are an example of a switching step in the present invention.

DESCRIPTION OF SYMBOLS 1 Head mounted display 2 Head mounting part 3 Frame 4 Half mirror 5 External light detection part 6 Switching part 7 Wearing detection part 8 Video input part 10 Video generation part 11 ROM
12 RAM
13 Light source controller 14 Light source 15 Display controller 16 Light modulator 17 CPU
18 System bus BD Setting brightness

Claims (8)

A display unit that is mounted in front of the user's eyes and displays video;
A switching unit that switches between a display state in which the display unit displays video and a non-display state in which the display unit does not display video;
A brightness adjusting unit that adjusts the brightness of an image displayed by the display unit;
An external light detection unit for detecting the external light amount,
The brightness adjusting unit is
When switching from one of the non-display state and the display state to the other by the switching unit, video from the luminance of the display unit in the non-display state to the luminance of the video displayed by the display unit in the display state A head-mounted display that adjusts a luminance change amount that changes per hour for increasing or decreasing the luminance according to the external light amount detected by the external light detection unit. The brightness adjusting unit is
When the switching unit switches from the non-display state to the display state, the luminance of the video is increased from the luminance of the display unit in the non-display state to the luminance of the video displayed by the display unit in the display state. The head mounted display according to claim 1, further comprising: an increase adjustment unit that adjusts a luminance change amount that changes per unit time to be adjusted according to the external light amount detected by the external light detection unit. The brightness adjusting unit is
When the display unit is switched from the display state to the non-display state by the switching unit, the luminance of the image is increased from the luminance of the image displayed by the display unit in the display state to the luminance of the display unit in the non-display state. The head-mounted display according to claim 1, further comprising a decrease adjustment unit that adjusts a luminance change amount that changes per unit time to decrease in accordance with the external light amount detected by the external light detection unit. A determination unit that determines whether the external light amount detected by the external light detection unit is greater than a predetermined value;
The brightness adjusting unit is
When the determination unit determines that the detected external light amount is greater than the predetermined value, the luminance change amount is adjusted to a first value,
2. The method according to claim 1, wherein when the determination unit determines that the detected external light amount is equal to or less than the predetermined value, the luminance change amount is adjusted to a second value smaller than the first value. The described head mounted display. The head-mounted display according to claim 1, further comprising a half mirror that is disposed in front of the user's eyes and reflects the image projected from the display unit to guide the image to the eyes. A mounting detection unit that detects whether or not the user has mounted the head mounted display;
The brightness adjusting unit is
When the mounting detection unit detects the mounting of the head mounted display, when the switching unit is switched between the display state and the non-display state, the luminance change amount is adjusted,
When the mounting detection unit does not detect the mounting of the head mounted display, the luminance change amount is not adjusted when the switching unit switches between the display state and the non-display state. The head mounted display according to claim 1. The display unit includes a light modulation unit that forms a spatial modulation pattern corresponding to the video;
A display control unit for drawing an image on the light modulation unit,
The brightness adjusting unit is
A light source that illuminates light from the back of the light modulator;
A light source control unit that adjusts the light amount of the light source,
The head mounted display according to claim 1, wherein the light source control unit adjusts the luminance change amount of an image displayed on the light modulation unit by adjusting a light amount of the light source. A brightness adjustment method for adjusting the brightness of an image displayed by a display unit provided in a head mounted display mounted in front of a user's eyes,
A switching step of switching between a display state in which the display unit displays video and a non-display state in which the display unit does not display video;
An outside light detection step for detecting the amount of outside light;
Adjusting the brightness of the video displayed by the display unit, and
The adjustment step includes
When switching from the non-display state to the display state in the switching step, the luminance of the video is increased from the luminance of the display unit in the non-display state to the luminance of the video displayed by the display unit in the display state. An increase adjustment step for adjusting the amount of change in luminance that changes per time for performing according to the external light amount detected by the external light detection step;
When the display state is switched from the display state to the non-display state in the switching step, the luminance of the video is increased from the luminance of the video displayed by the display unit in the display state to the luminance of the display unit in the non-display state. A brightness adjustment method for a head-mounted display, comprising: a reduction adjustment step for adjusting a luminance change amount that changes per unit time for reduction in accordance with the external light amount detected in the external light detection step.

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