JP4590914B2 - Image display device - Google Patents

Description

  The present invention relates to an image display apparatus that displays an image to an observer so that the depth of the image is expressed, and particularly relates to a technique for improving the accuracy with which the depth of the image is expressed.

  An image display device that displays an image to an observer so that the depth of the image is expressed is already known.

  One example of this type of image display apparatus is a wavefront of a light beam emitted from a light source between a light source (for example, a laser) and a scanner that two-dimensionally scans the light beam emitted from the light source on the observer's retina. This is an image display device of a type provided with a modulation unit that modulates curvature (see, for example, Patent Document 1). This example may be referred to as a retinal scanning display.

  In this retinal scanning display, a specific example of the “modulation unit” is a combination of a converging lens, a movable mirror, and an actuator, as disclosed in Patent Document 1. Specifically, the specific example includes (a) a frame, (b) a convergent lens that is fixed to the frame and receives light emitted from the emitting portion, and (c) a distance between the convergent lens is variable. A movable mirror that is mounted on the frame in a certain state and reflects light emitted from the converging lens; and (d) an actuator that moves the movable mirror along its optical axis to position it at an arbitrary position (for example, piezoelectric Actuator including an element as a drive source).

  Another example of the image display device described above is that the wavefront curvature of light emitted from the screen is modulated pixel by pixel or pixel group between the screen displaying the image two-dimensionally and the eyes of the observer. It is an image display device of a type provided with a possible lens array. Yet another example is an image display device of the type provided with an optical spatial phase modulator between such a screen and the observer's eye.

  In any case, this type of image display device emits from the emitting unit based on (a) an emitting unit (e.g., a light source) that emits light and (b) a depth signal that represents the depth of the image to be displayed. A modulation unit that modulates the wavefront curvature of light, and (c) an output unit that generates a depth signal based on an image signal representing an image to be displayed and outputs the depth signal to the modulation unit. As described above, in this type of image display apparatus, the modulation unit that modulates the wavefront curvature of light is arranged between the emitting unit and the observer so that the depth of the image is expressed. Is displayed.

  Here, the expression “the image is displayed so that the depth of the image is expressed” is, for example, regardless of whether the display target to be expressed by the display image is planar or stereoscopic. This means that the image is displayed so that the observer perceives that there is a distance between him and the displayed image. In this case, in order to improve the expression accuracy of the depth of the image, it is desirable that the distance perceived by the observer matches the distance preset in the display image as much as possible.

  In addition, the expression “the image is displayed so that the depth of the image is expressed” is, for example, when the display target to be expressed by the display image is stereoscopic, It means that an image is displayed so as to perceive that it has a three-dimensional shape. In this case, in order to improve the expression accuracy of the depth of the image, it is desirable that the three-dimensional shape perceived by the observer matches the three-dimensional shape preset for the display target as much as possible.

  Therefore, in this type of image display device, the modulation unit uses a format in which the wavefront curvature is modulated for each frame of the image (a plurality of portions constituting the same frame have a common wavefront curvature), or The wavefront curvature can be modulated for each part (for example, one pixel or pixel group) constituting one frame.

  In this type of image display apparatus, in order to express the depth of an image, a depth signal is generated based on an image signal representing an image to be displayed, and the generated depth signal is output to a modulation unit. On the other hand, between a plurality of products (individuals) belonging to the same type of image display device, if the command value of the depth represented by the depth signal, that is, the command value of the wavefront curvature is common to each other, it is realized by the modulation unit. It is necessary to make the wavefront curvatures, that is, the actual values of the wavefront curvatures, common to each other in order to reduce the variation among individuals regarding manufacturing quality. However, for example, there may be individual differences regarding the modulation unit.

  For example, in the retinal scanning display described in Patent Document 1, this individual difference occurs with respect to the distance between the convergent lens and the movable mirror at the origin position. In order to completely or partially eliminate this individual difference, an original point adjustment mechanism that moves the movable mirror along its optical axis and adjusts the origin position of the movable mirror is an original actuator that moves the movable mirror. Patent Document 1 discloses a technique for installing the projector independently.

  According to one specific example of the origin adjusting mechanism, a moving mechanism that moves the movable mirror and the original actuator together is provided, and the origin position of the movable mirror is adjusted by electrically operating the moving mechanism. Is done. The moving mechanism is configured as a combination of a motor and a feed screw, for example, and thus has a self-holding function, and can hold the position of the movable mirror even when the power is off. On the other hand, the original actuator normally has a self-recovery function that returns to the initial state when the power is off.

That is, Patent Document 1 proposes a technique for executing calibration of the origin position of the movable mirror using a special mechanism.
JP 2003-295108 A

  As described above, when a plurality of products (individuals) belonging to the same type of image display apparatus having a modulation unit between the emission unit and the observer share a depth command value represented by the image signal with each other In spite of this, an individual difference regarding the modulation unit is considered as a cause of the fact that the actual depth values realized by the modulation unit are not common to each other.

  The individual difference is typically caused by a manufacturing error of the modulation unit, that is, manufacturing variation, but the temperature of the environment where each of the plurality of products (individuals) is used (hereinafter referred to as “use temperature”) is different. It may be due to

  For these two types of factors, that is, manufacturing variations and operating temperatures, the characteristics of the error of the wavefront curvature caused by each factor are compared with each other, and the error of the wavefront curvature caused by the manufacturing error is determined by the use of the image display device. The error of the wavefront curvature caused by the use temperature is a variable error depending on the use temperature of the image display device, whereas it is a steady error regardless of the location and the use temperature.

  Therefore, in order to examine the characteristics of errors caused by these two types of factors in comparison with each other, focusing on the period of a series of image displays by the image display device, errors caused by manufacturing variations are While it does not vary with time, the error due to operating temperature can vary with time during image display. This is because, for example, during image display, the image display device may be moved to another place where the environment temperature is different and used, or even if the place of use is the same, the environment temperature of the place of use may change. It is.

  This will be specifically described by taking the retinal scanning display described in Patent Document 1 as an example. During a series of images displayed on the retinal scanning display, when the temperature of the frame on which the movable mirror and converging lens are mounted changes, the shape of the frame changes due to a phenomenon called thermal deformation (thermal expansion or contraction). To do. Along with the change, the distance between the movable mirror and the converging lens changes. Due to this change, the wavefront modulation of the light emitted from the modulation unit changes, and as a result, the depth of the expressed image is not stable.

  Therefore, even if calibration of the origin position of the movable mirror is performed in the image display device, it is performed only prior to a series of image display by the image display device and not performed during the series of image display. The fluctuation error of the wavefront curvature during a series of image display cannot be reduced.

  On the other hand, when the calibration of the origin position of the movable mirror is performed during a series of image display by the image display device, it is strongly desired to complete in a short time compared to the case of performing prior to the series of image display. The This is because it is desirable to perform the calibration without substantially affecting the display image in order to maintain the image quality.

  On the other hand, when the calibration of the origin position of the movable mirror is performed by moving the movable mirror and the original actuator together as described above, the calibration must be overcome for the calibration. Inertia (inertial mass or moment of inertia) increases compared to the case where it is sufficient to move the movable mirror alone. Therefore, when calibration is performed by moving the movable mirror and the original actuator together, it is not suitable for performing calibration at high speed.

  Based on the knowledge described above, the present invention has been made in order to improve the accuracy with which the depth of an image is expressed in an image display device that displays the image to an observer so that the depth of the image is expressed. Is.

In order to solve the problem, according to one aspect of the present invention, an image display device that displays an image to an observer so that the depth of the image is expressed,
An emission unit that emits light based on a luminance signal among video signals supplied from the outside to display the image;
A modulation unit that modulates the wavefront curvature of light emitted from the emission unit, thereby expressing the depth of the image, using a piezoelectric element as a drive source;
A scanning unit that two-dimensionally scans the light emitted from the modulation unit, the scanned light is projected onto the retina of the viewer, and the image is displayed to the viewer;
A detection unit for detecting a real wavefront curvature-related amount that is a wavefront curvature-related amount related to the wavefront curvature of the light emitted from the modulation unit and that is an actual value of an amount that changes according to the change of the wavefront curvature;
Based on the relationship between the detected actual wavefront curvature-related quantity and the ideal value of the wavefront curvature-related quantity, a correction value for the original depth signal, which is a depth signal of the video signal, is determined, and the determined correction A determining unit that generates a corrected depth signal based on the value and outputs the generated corrected depth signal to the modulation unit;
Including
The modulation unit modulates the wavefront curvature based on the corrected depth signal output from the determination unit,
The detection unit detects the real wavefront curvature related amount during execution of a series of image display by the image display device,
The determination unit generates the corrected depth signal based on the actual wavefront curvature-related amount detected by the detection unit during execution of a series of image displays by the image display device, and outputs the corrected depth signal to the modulation unit An apparatus is provided.
The following aspects are obtained by the present invention. Each aspect is divided into sections, each section is given a number, and is described in a form that cites other section numbers as necessary. This is to facilitate understanding of some of the technical features that the present invention can employ and combinations thereof, and the technical features that can be employed by the present invention and combinations thereof are limited to the following embodiments. Should not be interpreted. That is, it should be construed that it is not impeded to appropriately extract and employ the technical features described in the present specification as technical features of the present invention although they are not described in the following embodiments.

  Further, describing each section in the form of quoting the numbers of the other sections does not necessarily prevent the technical features described in each section from being separated from the technical features described in the other sections. It should not be construed as meaning, but it should be construed that the technical features described in each section can be appropriately made independent depending on the nature.

(1) An image display device that displays an image to an observer so that the depth of the image is expressed,
An emission part for emitting light;
A modulation unit that modulates the wavefront curvature of the light emitted from the emission unit based on a depth signal representing the depth of an image to be displayed;
An output unit that generates the depth signal based on an image signal representing an image to be displayed and an actual wavefront curvature related quantity that is an actual value of the wavefront curvature related quantity related to the wavefront curvature, and outputs the depth signal to the modulation unit; An image display device.

  In this image display device, a depth signal is generated based on an image signal representing an image to be displayed and an actual wavefront curvature related quantity that is an actual value of a wavefront curvature related quantity related to the wavefront curvature of light emitted from the emitting unit. It is generated and output to the modulation unit. Therefore, according to this image display device, it is possible to reflect the actual value of the wavefront curvature in the depth signal output to the modulation unit. As a result, the modulation unit is controlled so that the depth command value represented by the image signal, that is, the wavefront curvature command value, is accurately realized regardless of the presence or absence of disturbances that affect the actual value of the wavefront curvature. It becomes possible to do.

  As described above, in this image display apparatus, the control of the modulation unit for reducing the error of the wavefront curvature (hereinafter referred to as “error reduction control”) is simply performed without using a special mechanism. In other words, in order to modulate the wavefront curvature, it is electrically performed using a mechanism that the modulation unit originally has.

  Therefore, according to this image display device, since it is not essential to add a special mechanism for performing error reduction control of the modulation unit, an increase in the number of parts of the image display device and a corresponding increase in weight and cost increase. The error reduction control of the modulation unit can be performed while suppressing the above.

  This image display device can reduce the error regardless of whether the type of error occurring in the wavefront curvature is a steady error that does not vary with time during a series of image display or a variation error that varies. It is possible to implement in the first mode in which the modulation unit is simply electrically controlled. In this first aspect, during a series of image display, even if no fluctuation error occurs in the wavefront curvature, as long as there is a steady error, a depth signal is generated to reflect the steady error, thereby The modulation unit is electrically controlled.

  In contrast, the image display device according to this section reduces the steady-state error existing in the wavefront curvature by calibrating the modulation unit using a special mechanism having a self-holding function prior to a series of image display. On the other hand, during the series of image display, the modulation unit is simply electrically controlled by the depth signal reflecting the actual value of the wavefront curvature, thereby implementing the second aspect of reducing the variation error generated in the wavefront curvature. Is also possible. In the second aspect, as long as no variation error occurs during a series of image display, it is not necessary to perform electrical error reduction control of the modulation section, and power consumption can be saved.

  In both of the first and second modes, the electric error reduction control of the modulation unit can be performed during a series of image display. However, the magnitude of the steady-state error and the fluctuation error generated in the wavefront curvature are determined. In general, the fluctuation error is smaller than the steady-state error when compared with each other. In addition, regardless of whether the error occurring in the wavefront curvature is variable or stationary, the smaller the error, the lighter the complexity and load of the electrical error reduction control of the modulator.

  By the way, the longer the error reduction control has to be performed during image display, the higher the possibility that an adverse effect of the error reduction control will appear in the display image. However, in the first and second aspects described above, during the series of image display, the error reduction control can be completed in a shorter time than the error reduction control performed prior to the series of image display. . Therefore, according to the first and second aspects, it becomes easy to perform error reduction control without substantially affecting the display image, and as a result, it is expressed without causing deterioration in image quality. It becomes easy to improve the stability of the depth of the image.

  “Actual wavefront curvature related quantity” in this section refers to the actual value of the wavefront curvature when the modulator changes its state (for example, position, shape, temperature, mechanical property, electrical property, optical property, etc.). When the optical system to be changed is included, for example, it is the state of the optical system.

  Specifically, the “real wavefront curvature-related amount” in this section refers to two components (for example, the movable mirror and the convergent lens described above) that the modulation unit changes the actual value of the wavefront curvature when the mutual distance changes. ) Includes, for example, the distance between these two components. Further, when the modulation unit includes a component that changes the actual value of the wavefront curvature when the position of the modulation unit changes, for example, it is the position of the component. In addition, when the modulation unit includes a component (for example, the above-described frame) that changes the actual value of the wavefront curvature when the temperature of the modulation unit changes, the temperature is, for example, the component.

(2) The output unit
(A) a determination unit that determines a correction value for an original depth signal, which is a depth signal originally corresponding to the image signal, based on a relationship between an ideal value and an actual value of the wavefront curvature-related amount;
(B) A generation unit that generates a depth signal to be output to the modulation unit based on the determined correction value and at least one of the image signal and the original depth signal. Image display device.

  In this image display device, based on the relationship between the ideal value and the actual value of the wavefront curvature-related amount, a correction value for the original depth signal, which is a depth signal that originally corresponds to the image signal, is determined and determined. A depth signal to be output to the modulation unit is generated based on the correction value and at least one of the image signal and the original depth signal. Therefore, according to this image display apparatus, the depth signal actually output to the modulation unit reflects the actual value of the wavefront curvature by correcting the original depth signal in consideration of the actual value of the wavefront curvature. It becomes possible.

(3) Furthermore, the detection part which detects the said actual wavefront curvature related quantity is included, The said determination part determines the said correction value based on the actual wavefront curvature related quantity detected by the detection part (2) The image display device according to the item.

(4) The image display device according to (3), wherein the detection unit includes a pre-display detection unit that detects the real wavefront curvature related amount prior to a series of image display by the image display device.

  In this image display device, prior to a series of image display by the image display device, the actual wavefront curvature related amount is detected, and the correction value of the original depth signal is determined based on the detected value. Therefore, according to this image display device, for example, the correction value of the original depth signal is reduced so that the error of the wavefront curvature due to the manufacturing variation of the modulation unit and the local variation of the operating temperature of the image display device is reduced. As a result, it is possible to reduce the possibility that errors due to manufacturing variations and local variations in use temperature appear in the actual value of the wavefront curvature.

(5) The image display according to (3) or (4), wherein the detection unit includes a display detecting unit that detects the real wavefront curvature related amount during execution of a series of image display by the image display device. apparatus.

  In this image display device, during the execution of a series of image displays by the image display device, the actual wavefront curvature related amount is detected, and the correction value of the original depth signal is determined based on the detected value. Therefore, according to this image display device, for example, it is possible to determine the correction value of the original depth signal so that the error of the wavefront curvature due to the temporal variation of the operating temperature of the image display device is reduced. As a result, it is possible to reduce the possibility that an error due to temporal variation of the use temperature appears in the actual value of the wavefront curvature.

(6) The image display according to any one of (3) to (5), wherein the detection unit includes an optical sensor that detects the actual wavefront curvature-related amount by detecting light emitted from the modulation unit. apparatus.

  According to this image display device, the actual value of the wavefront curvature of the emitted light can be directly monitored by referring to the emitted light from the modulation unit. Therefore, according to the image display device, it is possible to correct the depth signal by monitoring the result of the error generated in the wavefront curvature, not the cause of generating the error in the wavefront curvature, thereby generating the error in the wavefront curvature. It is possible to correct the depth signal so that the wavefront curvature can be accurately realized regardless of the cause of the cause.

(7) The detection unit detects the actual wavefront curvature-related amount by the optical sensor in a light detection state in which the emission unit emits light in a set state and a set depth signal is output to the modulation unit. The image display device according to item (6).

  The actual wavefront curvature-related amount not only changes due to disturbance to the modulation unit, but may also change depending on the state (for example, wavelength) of incident light that exits from the emission unit and enters the modulation unit. May also change depending on the state (for example, command value) of the depth signal output to. Therefore, in order to accurately evaluate the actual wavefront curvature-related amount in comparison with the ideal wavefront curvature-related amount, it is desirable that the state of the incident light and the state of the depth signal are known.

  Based on such knowledge, in the image display apparatus according to this section, the actual wavefront curvature-related amount in the light detection state in which the emission unit emits light in the set state and the set depth signal is output to the modulation unit. Is detected.

  In this image display device, in order to accurately detect the actual wavefront curvature-related quantity using the light emitted from the light emitting part, the state in which the light emitting part emits light at the time of detection is known in advance. is important. This is because there is a possibility of dependency between the two. Therefore, in this image display device, when the actual wavefront curvature-related amount is detected, the emission unit emits light in a set state. Therefore, here, the “set state” is interpreted to mean that the emission state does not change with time (excluding that the emission state is different every time the actual wavefront curvature-related amount is detected). Should not be interpreted to mean that the exit condition is known. That is, it is sufficient if the emission state of the emitted light used for detecting the wavefront curvature related amount is known in advance, and it is excluded that the emission state is different every time the actual wavefront curvature related amount is detected. It should be interpreted as meaningless.

(8) During the execution of a series of image displays by the image display device, the detection unit emits light in a set state regardless of an image to be displayed, and is set in the modulation unit The image display device according to item (6), in which the real wavefront curvature-related amount is detected by the optical sensor in a light detection state in which a depth signal is output.

  During execution of a series of image displays by the image display device, if the emitted light from the modulation unit is blocked before reaching the observer, the image display may be substantially inhibited. It may not be done. As an example of the latter case, a non-image display area (for example, a part of the horizontal scanning blanking line or vertical scanning blanking line that is out of the image display area) is set outside the image display area. Another example, in which the light emitted from the modulation unit is irradiated, is the light emitted from the modulation unit in a period that does not substantially affect the image display (for example, during the vertical scanning blanking period). This is a case where it is possible to temporarily block the viewer from reaching the observer.

  When the emitted light from the modulation unit substantially hinders image display, the state of the emission unit is changed or the depth signal output to the modulation unit is detected for the purpose of highly accurate detection of the actual wavefront curvature related amount. It is difficult to change the state. On the other hand, when the light emitted from the modulation unit does not substantially hinder the image display, the state of the emission unit is changed or output to the modulation unit for the purpose of highly accurate detection of the actual wavefront curvature related amount. It is possible to change the state of the depth signal.

  Based on the knowledge described above, in the image display apparatus according to this section, the emission unit emits light in a set state regardless of the image to be displayed during execution of a series of image display, and the modulation unit In the light detection state in which the set depth signal is output, the actual wavefront curvature related amount is detected by the optical sensor.

(9) Furthermore,
A scanning unit that two-dimensionally scans light emitted from the modulation unit, and scans light not only in an image display region set for an observer but also in a non-image display region set outside the image display region. What is possible to do,
A light-shielding unit that is provided between the modulation unit and an observer, and allows light directed from the modulation unit to the image display region to pass therethrough, and blocks light directed to the non-image display region, and
The detection unit emits light in a set state during execution of a series of image displays by the image display device, and a set depth signal is output to the modulation unit, and from the modulation unit The state in which the emitted light is scanned in the direction toward the non-image display region by the scanning unit is set as the light detection state, and the real wavefront curvature related amount is detected by the optical sensor in the light detection state. The image display device according to item (8).

  According to this image display device, during a series of image display, in a state where the light emitted from the modulation unit and directed to the non-image display area is prevented from reaching the observer by the light shielding unit, By using this, it is possible to detect the actual wavefront curvature related amount without substantially obstructing the display image observed by the observer.

(10) The image display device according to (9), wherein the detection unit is configured to detect the real wavefront curvature related amount by the optical sensor during a blanking period in scanning by the scanning unit.

  The scanning lines include an effective line that directly contributes to image display (a scanning line that actually transmits an image signal) and a return line that does not contribute directly. Of these, when detecting the actual wavefront curvature-related quantity using the return line, the detection of the actual wavefront curvature-related quantity is substantially equivalent to the image display compared to the case of detecting using the effective line. It may be easy to do without impact.

  Based on such knowledge, in the image display device according to this section, the actual wavefront curvature-related amount is detected by the optical sensor during the blanking period in scanning.

(11) The scanning unit performs horizontal scanning for scanning light emitted from the emitting unit in a horizontal direction and vertical scanning for scanning in a vertical direction.
The image display device according to (10), wherein the detection unit is configured to detect the actual wavefront curvature-related amount by the optical sensor during a blanking period in the vertical scanning.

  Comparing the length of one blanking period with respect to the vertical scanning and the horizontal scanning, the vertical scanning is usually longer than the horizontal scanning. On the other hand, the longer the blanking period, the easier it is to detect the actual wavefront curvature related amount with a time margin.

  Based on such knowledge, in the image display apparatus according to this section, the actual wavefront curvature-related amount is detected by the optical sensor during the blanking period in the vertical scanning.

(12) Further, a transmission permission state that is provided between the modulation unit and the observer and allows light emitted from the modulation unit to pass therethrough, and a blocking state that blocks light emitted from the modulation unit, Including a shutter that switches to
The detector is
(A) an optical sensor for detecting the real wavefront curvature-related amount by detecting light emitted from the modulation unit;
(B) In a light detection state in which the emission unit emits light in a set state, a set depth signal is output to the modulation unit, and light emitted from the modulation unit is blocked by the shutter, The image display device according to item (3), further including: a detecting unit that detects the actual wavefront curvature-related amount by an optical sensor.

  According to this image display device, it is possible to detect the actual wavefront curvature related amount using the emitted light in a state where the emitted light from the modulation unit is blocked and does not reach the observer.

(13) The detecting unit during blocking detects the actual wavefront curvature related amount prior to a series of image display by the image display device, and the actual wavefront curvature related amount during execution of the series of image display. The image display device according to item (12), which performs at least one of detection.

(14) The modulation unit includes an optical system that changes the actual value of the wavefront curvature when the state of the modulation unit changes.
The image display device according to any one of (3) to (13), wherein the detection unit includes a state sensor that detects a state of the optical system.

(15) The optical system includes two components that cause a change in the actual value of the wavefront curvature when the mutual distance changes,
The image display device according to any one of (3) to (14), wherein the detection unit includes a distance sensor that detects a distance between the two components.

  An example of “two components” in this section is two opticals having an electro-optic effect in which the refractive index changes according to the strength of an electric field applied in a direction perpendicular to the traveling direction of incident light. Elements (for example, optical waveguides made of PZT) are arranged at a fixed distance on a common optical axis.

  In this example, light that is incident on the first optical element from the emitting portion and is emitted from the first optical element is incident on the second optical element and is emitted from the second optical element. Originally, the wavefront curvature of the emitted light should depend only on the electric field applied to at least one of the optical elements. However, when the distance between the optical elements varies due to a disturbance such as temperature, the wavefront curvature of the light emitted from the second optical element also varies. Therefore, in this example, the actual distance between these optical elements is monitored, and the depth signal output to the modulation unit is corrected according to the actual distance, so that the actual value of the wavefront curvature is stabilized despite disturbance. It is desirable to

  Another example of the “two components” in this section is two lenses (for example, a ball lens) made of glass whose refractive index changes depending on the wavelength of incident light and whose characteristics are stronger than ordinary glass. ) And arranged at a fixed distance on a common optical axis.

  In this example, light that has entered the first lens from the emitting portion and has exited from the first lens enters the second lens and exits from the second lens. Originally, the wavefront curvature of the emitted light should depend only on the wavelength of the light incident on the first lens. However, when the distance between the lenses varies due to disturbances such as temperature, the wavefront curvature of the light emitted from the second lens also varies. Therefore, in this example, monitoring the actual distance between these lenses and correcting the depth signal output to the modulation unit according to the actual distance stabilizes the actual value of the wavefront curvature despite disturbance. Desirable to do.

(16) The two components include a lens on which the light emitted from the emitting portion is incident, and a mirror that reflects the light emitted from the lens toward the lens, and the reflected light from the mirror is The image display device according to item (15), wherein a wavefront curvature of light incident on the lens and emitted from the lens changes according to a distance between the lens and the mirror.

  An example of the “lens” in this section is the convergent lens described above, and an example of the “mirror” is the movable mirror described above.

(17) The optical system includes a component that causes a change in the actual value of the wavefront curvature when the position of the optical system changes,
The image display device according to any one of (3) to (16), wherein the detection unit includes a position sensor that detects a position of the component.

(18) The optical system includes a component that causes a change in the actual value of the wavefront curvature when the temperature of the optical system changes,
The image display device according to any one of (3) to (17), wherein the detection unit includes a temperature sensor that detects at least one of a temperature of a component and a temperature around the component.

  Hereinafter, some of more specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 systematically shows a retinal scanning display (hereinafter abbreviated as “RSD”) according to the first embodiment of the present invention. In this RSD, the laser beam is incident on the image plane of the retina 14 through the pupil 12 of the observer's eye 10 while appropriately modulating the brightness and wavefront curvature thereof, and the laser beam is incident on the image plane. The apparatus projects an image directly on the retina 14 by scanning in two dimensions.

  This RSD includes a light source unit 20 and includes a wavefront curvature modulator 22 and a scanning device 24 arranged in that order between the light source unit 20 and the eye 10 of the observer.

  The light source unit 20 includes an R laser 30 that emits a red laser beam and a green laser for focusing three laser beams having three primary colors (RGB) into one laser beam to generate a laser beam of an arbitrary color. A G laser 32 that emits a beam and a B laser 34 that emits a blue laser beam are provided. Each of the lasers 30, 32, and 34 can be configured as a semiconductor laser, for example.

  Each laser 30, 32, 34 has a luminance modulation function for modulating the luminance (light intensity) of the laser beam of each color emitted from each laser 30, 32, 34 in accordance with the input voltage signal (drive signal). ing.

  As shown in FIG. 1, corresponding laser drivers 36, 37, and 38 are electrically connected to the lasers 30, 32, and 34. An R luminance signal, which is a luminance signal for modulating the luminance of the red laser beam, is supplied from the signal processing circuit 39 to the laser driver 36 corresponding to the R laser 30, and the laser driver 37 corresponding to the G laser 32 is supplied to the laser driver 37. A G luminance signal, which is a luminance signal for modulating the luminance of the green laser beam, is supplied from the signal processing circuit 39, and the laser driver 37 corresponding to the B laser 34 is modulated to modulate the luminance of the blue laser beam. The B luminance signal, which is the luminance signal of, is supplied from the signal processing circuit 39.

  Each laser driver 36, 37, 38 applies each voltage (electric energy) corresponding to each inputted luminance signal to each laser 30, 32, 34. Each laser 30, 32, 34 modulates the brightness of the laser beam emitted from each laser 30, 32, 34 in accordance with the applied voltage.

  Laser beams emitted from the lasers 30, 32, and 34 are collimated by the collimating optical systems 40, 42, and 44 and then incident on the dichroic mirrors 50, 52, and 54. In these dichroic mirrors 50, 52, and 54, the laser beam is selectively transmitted and reflected depending on the wavelength, whereby the three color laser beams are combined into one laser beam.

  Specifically, the red laser beam emitted from the R laser 30 is collimated by the collimating optical system 40 and then incident on the dichroic mirror 50. The green laser beam emitted from the G laser 32 is incident on the dichroic mirror 52 through the collimating optical system 42. The blue laser beam emitted from the B laser 34 is incident on the dichroic mirror 54 via the collimating optical system 44.

  The three-color laser beams incident on the three dichroic mirrors 50, 52, and 54 are finally incident on one dichroic mirror 54 that represents the three dichroic mirrors 50, 52, and are then focused. The light is collected by the coupling optical system 58.

  The light source unit 20 described above causes the coupling optical system 58 to emit a laser beam. The laser beam emitted from the laser beam passes through an optical fiber 82 as an optical transmission medium and a collimating optical system 84 that collimates the laser beam emitted from the rear end of the optical fiber 82 in that order. 22 is incident.

  The wavefront curvature modulator 22 is an optical system that modulates the wavefront (wavefront curvature) of the laser beam emitted from the light source unit 20. The wavefront curvature modulator 22 can be in a form in which the wavefront curvature is modulated for each pixel of the image to be projected onto the retina 14, but this is essential for carrying out the present invention. Instead, it is possible to adopt a format for every frame of an image. Modulating the wavefront curvature means changing the perspective of the display image or changing the focus position of the display image.

  In any case, the wavefront curvature modulator 22 modulates the wavefront of the laser beam incident on the wavefront curvature modulator 22 based on the depth signal input from the signal processing circuit 39. In this wavefront curvature modulator 22, the laser beam incident as parallel light from the collimating optical system 84 is converted into convergent light by the converging lens 90, and the converted convergent light is reflected by the movable mirror 92 and converted into diffused light. Is done. The converted diffused light is emitted from the wavefront curvature modulator 22 as a laser beam having a target wavefront curvature.

  FIG. 2 shows the wavefront curvature modulator 22 in an enlarged manner. As shown in FIG. 2, the wavefront curvature modulator 22 includes a beam splitter 94 that reflects or transmits a laser beam (incident light) incident from the outside, and a converging lens that converges the laser beam incident through the beam splitter 94. 90 and a movable mirror 92 that reflects the laser beam converged by the converging lens 90.

  The wavefront curvature modulator 22 further includes an actuator 96 that displaces the movable mirror 92 toward or away from the converging lens 90. An example of the actuator 96 is a piezoelectric element. The actuator 96 modulates the wavefront curvature of the laser beam emitted from the wavefront curvature modulator 22 by moving the position of the movable mirror 92 according to the depth signal input from the signal processing circuit 39.

  In the wavefront curvature modulator 22 configured as described above, the laser beam incident from the collimating optical system 84 is reflected by the beam splitter 94, passes through the converging lens 90, and then is reflected by the movable mirror 92. Then, it passes through the converging lens 90 again, and then passes through the beam splitter 94 toward the scanning device 24.

  The wavefront curvature modulator 22 changes the wavefront curvature of the laser beam incident from the collimating optical system 84 and traveling toward the scanning device 24 by changing the distance dc between the converging lens 90 and the movable mirror 92 using the actuator 96. can do.

  As shown in FIG. 2, when the distance dc coincides with a predetermined initial value dc0 (equal to the focal length f of the converging lens 90), the laser beam incident from the collimating optical system 84 is moved to the movable mirror 92. The light is converged and reflected on the reflection surface. The reflected laser beam passes through the converging lens 90 and the beam splitter 94 in order, and travels toward the scanning device 24 as parallel light (emitted light) L1 having the same wavefront curvature as that incident from the collimating optical system 30.

  On the other hand, as shown in FIG. 3, when the distance dc changes to a distance dc1 shorter than the initial value dc0, the laser beam incident from the collimating optical system 84 is converged by the movable mirror 92 from the focal point of the converging lens 90. Since it is located near the lens 90, it is incident on the reflecting surface of the movable mirror 92 and reflected before the laser beam converges. The reflected laser beam converges at a position advanced by a distance (dc0−dc1) from the movable mirror 92, and then diffused light having a larger wavefront curvature that is diffused when incident from the collimating optical system 84, that is, a radius of curvature. Diffused light (emitted light) L 2, passes through the converging lens 90 and the beam splitter 94 in this order, and travels toward the scanning device 24. As shown in FIG. 3, the diffused light L <b> 2 is light emitted from a light emitting point that is apparently located behind the reflecting surface of the movable mirror 92.

  In short, the radius of curvature of the laser beam traveling from the wavefront curvature modulator 22 to the scanning device 24 decreases as the distance dc decreases. In the present embodiment, the initial value dc0 of the distance dc is set to 4 mm, and the radius of curvature of the laser beam is minimized from the maximum value (for example, 10 m) while the distance dc is narrowed by 30 μm from the initial value dc0. This RSD is configured to vary up to a value (eg, 20 cm).

  In general, the radius of curvature of the wavefront of the laser beam is represented by the reciprocal of the wavefront curvature, and the virtual image based on the laser beam is recognized by the observer at a position closer to the observer as the radius of curvature is smaller. Therefore, the virtual image is recognized by the observer at a position closer to the observer as the distance dc is shortened by the actuator 96.

  As is clear from the above description, in the present embodiment, when the distance dc between the converging lens 90 and the movable mirror 92 changes, the wavefront curvature and the radius of curvature of the light emitted from the wavefront curvature modulator 22 are accordingly changed. Change. Therefore, if the distance dc is not normal due to manufacturing errors, thermal deformation, or other events of the frame that supports the converging lens 90 and the movable mirror 92 in the wavefront curvature modulator 22, an error occurs in the wavefront curvature. End up.

  Therefore, in this embodiment, the actual value of the wavefront curvature is detected, and the depth signal to be output to the actuator 96 is corrected accordingly.

  On the other hand, if the wavefront curvature of the outgoing light from the wavefront curvature modulator 22 changes, the beam diameter of the outgoing light also changes, and accordingly, the outer peripheral position of the cross section of the outgoing light also changes. Specifically, the smaller the wavefront curvature of the emitted light, the smaller the beam diameter of the emitted light, and the outer peripheral position of the transverse section of the emitted light approaches the beam optical axis. Conversely, the larger the wavefront curvature of the emitted light, the larger the beam diameter of the emitted light, and the outer peripheral position of the transverse section of the emitted light is separated from the beam optical axis.

  Therefore, for example, if the amount of the emitted light is locally detected at the outer peripheral position of the cross section and the detected value is compared with the ideal value, it is possible to determine whether there is an error in the wavefront curvature.

  Based on such knowledge, in this embodiment, as shown in FIG. 1, the received light amount detection device 97 is provided in association with the wavefront curvature modulator 22. As shown in FIGS. 2 and 3, the received light amount detection device 97 includes a line CCD sensor 98 as an optical sensor. The line CCD sensor 98 includes CCDs as light receiving elements arranged in a line. As shown in FIGS. 2 and 3, the line CCD sensor 98 receives the laser beam emitted from the converging lens 90, incident on the beam splitter 94 and reflected by the beam splitter 94 as reference light.

  The line CCD sensor 98 is in the vicinity of the outer peripheral position of the cross-section of the reference light, and when the beam diameter of the reference light changes, the light of the reference light is changed to a position where the amount of light received by the line CCD sensor 98 also changes. It is fixed in a posture extending in a direction intersecting the axis (for example, a direction perpendicular to the axis).

  The smaller the wavefront curvature of the reference light and the smaller the beam diameter thereof, the smaller the amount of light received by the line CCD sensor 98. On the other hand, the amount of light received by the line CCD sensor 98 increases as the wavefront curvature of the reference light increases and the beam diameter increases. Thus, a certain relationship is established between the wavefront curvature and the amount of received light.

  Focusing on this fact, for example, when the reference light should ideally be parallel light, as shown in FIG. 2, if the line CCD sensor 98 receives the actual reference light as parallel light, as shown in FIG. Based on the amount of received light, it is possible to determine that the wavefront curvature of the light emitted from the wavefront curvature modulator 22 is normal. On the other hand, as shown in FIG. 3, if the line CCD sensor 98 receives the actual reference light as the diffused light, the wavefront curvature of the light emitted from the wavefront curvature modulator 22 is abnormal based on the amount of the received light. Can be determined. Further, based on the amount of received light, it is possible to grasp how far the actual value of the wavefront curvature deviates from the ideal value (0 in this example).

  In the present embodiment, each of the plurality of CCDs constituting the line CCD sensor 98 is treated as a binary switch, and the two states of the state where the amount of light received by each CCD exceeds the threshold value and the state where it does not exceed the threshold value are discriminated. For this purpose, a line CCD sensor 98 is used. Therefore, the amount of received light detected using the line CCD sensor 98 is not affected by the change in the intensity, that is, the density of light incident on each CCD, as compared with the case where each CCD is handled as an analog sensor. Therefore, the amount of received light detected using the line CCD sensor 98 accurately reflects the light receiving area, and thus accurately reflects the beam diameter of the reference light.

  The light receiving amount detection device 97 has been described in detail with respect to only the line CCD sensor 98, but the whole including other elements will be described in detail later.

  As shown in FIG. 1, the laser beam emitted from the wavefront curvature modulator 22 enters the scanning device 24. The scanning device 24 includes a horizontal scanning system 100 and a vertical scanning system 102.

  The horizontal scanning system 100 is an optical system that performs horizontal scanning in which a laser beam is raster-scanned horizontally along a plurality of horizontal scanning lines for each frame of an image to be displayed. On the other hand, the vertical scanning system 102 is an optical system that performs vertical scanning in which a laser beam is scanned vertically from the first scanning line toward the last scanning line for each frame of an image to be displayed.

  Specifically, in the present embodiment, the horizontal scanning system 100 includes a polygon mirror 104 as a unidirectional rotating mirror that performs mechanical deflection. The polygon mirror 104 is rotated at a high speed by a motor (not shown) around a rotation axis intersecting the optical axis of the laser beam incident thereon. The rotation speed of the polygon mirror 104 is controlled based on a horizontal synchronization signal supplied from the signal processing circuit 39.

  The polygon mirror 104 includes a plurality of reflecting surfaces 106 arranged around the rotation axis, and is deflected once each time the incident laser beam passes through one reflecting surface 106.

  The horizontal scanning system 100 forms an effective scanning line from the start point to the end point in the horizontal direction in order to decompose the image into pixels in order to transmit an image signal, and from the end point of one effective scanning line to the next. A return line for returning to the start point of the effective scan line is formed as a horizontal scan return line. During the horizontal scanning blanking period, in order to improve the image quality, no laser beam is output from the light source composed of the lasers 30, 32 and 34, or is output so as not to reach the observer's eye 10.

  The laser beam deflected by the polygon mirror 104 is transmitted to the vertical scanning system 102 by the relay optical system 110.

  The vertical scanning system 102 includes a galvanometer mirror 130 as a swinging mirror that performs mechanical deflection. A laser beam emitted from the horizontal scanning system 100 is collected by the relay optical system 110 and enters the galvanometer mirror 130. The galvanometer mirror 130 is swung around a rotation axis that intersects the optical axis of the laser beam incident thereon. The start timing and rotation speed of the galvanometer mirror 130 are controlled based on the vertical synchronization signal supplied from the signal processing circuit 39.

  The vertical scanning system 102 forms an effective scanning line from the start point to the end point in the vertical direction in order to decompose the image into pixels in order to transmit an image signal. Further, from the end point of one effective scanning line to the next A return line for returning to the start point of the effective scan line is formed as a vertical scan return line. During the vertical scanning blanking period, in order to improve the image quality, no laser beam is output from the light source composed of the lasers 30, 32 and 34, or is output so as not to reach the observer's eye 10.

  In cooperation with the horizontal scanning system 100 and the vertical scanning system 102 described above, the laser beam is scanned two-dimensionally, and an image represented by the scanned laser beam passes through the relay optical system 140 to the eyes of the observer. 10 is irradiated.

  As shown in FIG. 1, the RSD includes a light shielding plate 150 between the scanning device 24 and an observer. In this embodiment, the light shielding plate 150 is disposed on the downstream side of the vertical scanning system 102, and specifically, is disposed on the downstream side of the relay optical system 140.

  As shown in FIG. 4, in the RSD, an image display area is set for the observer. In the RSD, the image is displayed in accordance with the image signal in cooperation with horizontal scanning and vertical scanning. indicate. Therefore, the observer can observe the image only in this image display area. However, in the present embodiment, the scanning area that can be scanned by the scanning device 24 is set wider than the image display area, and each effective scanning line includes a portion that is out of the image display area. However, the removed part is erased so that it is not recognized by the observer. As a result, a non-image display area where no image is displayed exists outside the image display area, specifically, at the outer periphery.

  In this non-image display area, if each effective scanning line is erased for a portion outside the image display area, and each return line is erased as a whole, this non-image display area is present. Nevertheless, the observer observes the image only in the image display area.

  However, in the present embodiment, the scanning period of the scanning device 24, in particular, the period in which the vertical scanning system 102 emits the laser beam toward the non-image display region in the vertical scanning blanking period of the vertical scanning system 102 is received. This is a quantity detection period, and the received light quantity of the reference light is detected during the received light quantity detection period. Therefore, if the term erasing the vertical scanning blanking, which is a scanning line unnecessary for the observer, is used in the sense of preventing the light forming the vertical scanning blanking from reaching the observer, the vertical scanning blanking is used. In this embodiment, the line is erased by temporarily stopping the lasers 30, 32, and 34 for the portion corresponding to the image display area, while the portion corresponding to the non-image display area is shielded from light. This is done by the plate 150.

  Furthermore, in the present embodiment, at least one of the three lasers 30, 32, and 34 emits a laser beam in a set state (a state having a set wavelength and a set brightness) during the above-described received light amount detection period. In addition, in the present embodiment, a depth signal to be output to the actuator 96 is output to the actuator 96 in order to make the light emitted from the wavefront curvature modulator 22 parallel light. The Therefore, in this light reception amount detection period, when the wavefront curvature modulator 22 is in a normal state without manufacturing errors and temperature fluctuations, the emitted light (reference light) from the wavefront curvature modulator 22 is parallel light, That is, the light has a wavefront curvature of 0 and a radius of curvature of infinity.

  Therefore, in this light reception amount detection period, light is emitted from the wavefront curvature modulator 22 even though image display should not be performed. The aforementioned light shielding plate 150 is provided so that the emitted light does not reach the observer. The light shielding plate 150 is generally constituted by an opaque body having an opening corresponding to the image display area. The shape and size of the opening are designed so that light that is directed from the scanning device 24 toward the observer is blocked from reaching the non-image display area.

  FIG. 5 conceptually shows the overall configuration of the RSD in a block diagram. As described above, the light source unit 20 is related to light emission and includes the three lasers 30, 32, and 34 and the three laser drivers 36, 37, and 38. A portion of the signal processing circuit 39 that controls the laser drivers 36, 37, and 38 is an image signal control unit 154. The light source unit 20 further includes an actuator driver 156 related to wavefront modulation. The actuator driver 156 is electrically connected to the actuator 96 described above. A portion of the signal processing circuit 39 that controls the actuator driver 156 is a wavefront curvature controller 158. The wavefront curvature control unit 158 receives the depth signal from the image signal control unit 154.

  As shown in FIG. 5, the light source unit 20 further includes a horizontal scanning system driver 160 and a vertical scanning system driver 162. The horizontal scanning system driver 160 and the vertical scanning system driver 162 are electrically connected to the horizontal scanning system 100 and the vertical scanning system 102, respectively. The horizontal scanning system driver 160 and the vertical scanning system driver 162 receive the horizontal synchronization signal and the vertical synchronization signal from the image signal control unit 154, respectively, and also perform transmission / reception between them.

  As shown in FIG. 5, the light emitted from the lasers 30, 32, and 34 enters the wavefront curvature modulator 22, and the wavefront curvature modulator 22 controls the wavefront curvature. The light whose wavefront curvature is controlled in this way is emitted from the wavefront curvature modulator 22, and the emitted light passes through the horizontal scanning system 100, the vertical scanning system 102, and the light shielding plate 150 in that order to the observer's eye 10. Incident.

  As shown in FIG. 5, the received light amount detection device 97 calculates the received light amount by processing the received light amount detector 170 including the above-described line CCD sensor 98 and the output signal of the line CCD sensor 98. And a received light amount calculation unit 172. The received light amount calculation unit 172 transmits a signal or data representing the calculated received light amount to the wavefront curvature control unit 158 described above.

  The wavefront curvature control unit 158, as will be described in detail later, is based on the received light amount received from the received light amount detection device 97, and the correction amount or offset for the depth signal received from the image signal control unit 154, that is, the original depth signal. This is an example of “correction value” in item 2). The wavefront curvature control unit 158 further adds the determined offset to the depth signal received from the image signal control unit 154, that is, the original depth signal, and outputs the corrected depth signal thus obtained to the actuator driver 156. To do.

  As a result, the actuator driver 156 and thus the actuator 96 have a depth signal received from the image signal control unit 154 (a signal indicating a command value of the wavefront curvature) and a received light amount received from the received light amount detection device 97 (actual value of the wavefront curvature). And this is an example of the “real wavefront curvature-related amount” in the above item (1)). Therefore, the actual value of the wavefront curvature accurately matches the command value of the wavefront curvature despite the manufacturing error of the wavefront curvature modulator 22, disturbances such as temperature fluctuations, and fluctuations in the distance dc caused by other events. It will be.

  As described above, according to the present embodiment, the fluctuation of the wavefront curvature caused by the fluctuation of the distance dc is absorbed by the software process of correcting the depth signal, and as a result, the stability of the wavefront curvature is improved.

  As shown in FIG. 6, the signal processing circuit 39 is mainly configured by a computer 190 having a CPU 180, a ROM 182, a RAM 184, and a bus 186 that connects them together. However, such a configuration is not indispensable for carrying out the present invention, and the signal processing circuit 39 can be configured as a DSP, for example.

  As shown in FIG. 6, the ROM 182 stores various programs in advance, including a pre-display offset setting program and an image display program.

  In brief, the pre-display offset setting program detects the actual value of the wavefront curvature prior to the series of image display by the RSD, and adds the actual value to the original depth signal in order to approach the ideal value. Executed by computer 190 to set the power offset. On the other hand, the image display program is a program executed by the computer 190 in order to realize a series of image display by the RSD, and a series of image display by the RSD is being executed, and a vertical scanning blanking period. It includes steps executed by the computer 190 to detect the actual value of the wavefront curvature and set an offset to be added to the original depth signal to bring the actual value closer to the ideal value.

  As shown in FIG. 6, the RAM 184 stores data representing the offset value set by executing the pre-display offset setting program. The value of the offset is updated so as to be replaced with the value of the offset set by the execution after the execution of the image display program.

  FIG. 7 conceptually shows the contents of the pre-display offset setting program in a flowchart. This pre-display offset setting program is executed at least once automatically or in response to a user's request prior to a series of image display after the RSD is turned on.

  If this pre-display offset setting is executed, first, in step S1 (hereinafter, simply referred to as “S1”, the same applies to other steps), a depth signal for moving the movable mirror 92 to the origin position. Is output to the actuator driver 156. When the depth signal is output to the actuator driver 156, the light emitted from the wavefront curvature modulator 22 becomes parallel light on condition that the distance dc is equal to the initial value dc0 (= focal length f).

  Next, in S2, a luminance signal for displaying a test image is output to the laser drivers 36, 37, and 38. The luminance signal is output to only one of the laser drivers 36, 37, and 38. As a result, the wavelength of the laser beam emitted for detecting the amount of received light is unified.

  A test image is output by the output of such a luminance signal. The purpose of this is to detect the actual value of the received light amount (hereinafter referred to as “actual received light amount”) R1 reflecting the actual value of the wavefront curvature. . Therefore, at this stage, it is desirable to temporarily close the exit of the RSD with an opaque cap or the like so that light does not enter the user's eyes from the RSD.

  When a luminance signal for displaying a test image is output to the laser drivers 36, 37, and 38, a corresponding drive signal is output to the lasers 30, 32, and 34. As a result, the laser beams from the lasers 30, 32, and 34 are output. Is emitted. A test image is displayed by the emitted laser beam.

  That is, in the present embodiment, the depth signal for moving the movable mirror 92 to the origin position is an example of the “set depth signal” in the item (7), and the laser driver 36, The light emission state realized by the luminance signals output to 37 and 38 is an example of the “setting state” in the same term, and the state in which the test image is displayed is an example of the “light detection state” in the same term. That's it.

  Subsequently, in S3, the received light amount detection device 97 is operated using the line CCD sensor 98, whereby the actual received light amount R1 is detected. This actual amount of received light R1 depends on the actual value of the wavefront curvature COW (Curvature of Wavefront) of the light emitted from the wavefront curvature modulator 22, and more specifically, as shown in the graph of FIG. When the incident light is parallel light, it matches the ideal received light amount R10. When the emitted light is diffused light, the value is larger than the ideal received light amount R10, and when the emitted light is convergent light. The value is smaller than the ideal received light amount R10. Further, the difference ΔR1 of the actual received light amount R1 from the ideal received light amount R10 increases monotonously as the actual value of the wavefront curvature COW deviates from the ideal value (0 in this case). When the detection of the actual received light amount R1 is completed, the output of the test image is terminated.

  Thereafter, in S4 of FIG. 7, the above-described difference ΔR1 is calculated. This difference ΔR1 is, for example,

  ΔR1 = R1-R10

It is calculated using the following formula.

  Subsequently, in S5, the aforementioned offset is determined in accordance with the calculated difference ΔR1. The relationship between the difference ΔR1 and the offset is stored in advance in the ROM 182, and the offset corresponding to the current difference ΔR1 is determined according to the relationship. Thereafter, in S6, the determined offset is stored in the RAM 184.

  This completes one execution of the pre-display offset setting program.

  FIG. 9 conceptually shows the contents of the image display program in a flowchart. This image display program is repeatedly executed after an RSD image display start switch (not shown) is operated by the user.

  When executing this image display program each time, first, in S101, an image output mode is started. As a result, horizontal scanning and vertical scanning are performed in order to sequentially convert the video signal into pixels. Next, in S102, a video signal, that is, an image signal is input. The video signal includes an R / G / B luminance signal and an original depth signal.

  Subsequently, in S103, the input luminance signal is output to the laser drivers 36, 37, and 38. Thereafter, in S104, the above-described offset is read from the RAM 184. Subsequently, in S105, the read offset is corrected by adding the read offset to the input original depth signal. Thereafter, in S106, the corrected depth signal is output to the actuator driver 156. With the execution of S102 to S106, an image is displayed to the observer.

  Subsequently, in S107, the arrival of the vertical scanning blanking period is awaited. If it has arrived, in S108, a depth signal for returning the movable mirror 92 to the origin position is output to the actuator driver 156 in the same manner as in S1 of FIG.

  As shown in FIG. 4, the vertical scanning blanking period includes a period corresponding to the image display area and a period corresponding to the non-image display area, and the latter period corresponds to the first non-image display area. Period (lower part in FIG. 4) and a period corresponding to the second non-image display area (upper part in FIG. 4). In the present embodiment, the period corresponding to the first non-image display area is assigned to the period for detecting the amount of light received from the wavefront curvature modulator 22, and during this period, the depth signal is transmitted to the actuator. It is output to the driver 156.

  Thereafter, in S109 of FIG. 9, as in S2 of FIG. 7, a luminance signal for outputting a test image is output to the laser drivers 36, 37, and 38, thereby outputting a test image.

  That is, in the present embodiment, the above-described depth signal is an example of the “set depth signal” in the item (7) or (8), and is output to the laser drivers 36, 37, and 38 for displaying a test image. The light emission state realized by the luminance signal is an example of the “setting state” in the item (7) or (8), and the state in which the test image is displayed is the item (7) or (8). This is an example of the “light detection state” in the section.

  Subsequently, in S110, the actual received light amount R2 is detected by the received light amount detection device 97 in the same manner as S3 in FIG. Thereafter, in S111, the output of the test image is terminated, and further, the luminance signal is erased so that the portion subsequent to the portion corresponding to the first non-image display area in the vertical scanning blanking of this time is erased. Is controlled.

  Thereafter, in S112, the difference ΔR2 between the detected actual received light amount R2 and the ideal received light amount R20 is calculated in the same manner as S4 in FIG. Subsequently, in S113, an offset is determined in accordance with the calculated difference ΔR2, similarly to S5 of FIG. Thereafter, in S114, the offset value stored in the RAM 184 is updated so as to be equal to the determined offset value.

  Subsequently, in S115, it is determined whether or not the current image display mode should be terminated based on a user instruction or the like. If it is assumed that this time is not to be terminated, the determination is NO, and the process returns to S102. However, if this time is assumed to be the case in which the process is to be terminated, the determination is YES. One execution of the image display program ends.

  In addition, it is not essential to operate the scanning device 24 to detect the wavefront curvature prior to the image display. However, when the scanning device 24 is operated prior to the image display, a portion corresponding to the non-image display area in the vertical scanning blanking period is obtained by a method similar to the method of detecting the wavefront curvature during the image display. Furthermore, light emission for wavefront curvature detection can be performed without irradiating the observer with light. In this way, prior to image display, the RSD exit port is not obstructed with the cap in order to prevent the light emitted to detect the wavefront curvature from being applied to the eye 10 of the observer. It will end.

  To explain the relationship between the pre-display offset setting program and the image display program described above, and the image signal control unit 154 and the wavefront curvature control unit 158 in FIG. 5, the image signal control unit 154 includes: The wavefront curvature control unit 158 includes a part that executes the pre-display offset setting program of FIG. 7 in the signal processing circuit 39, and S104 in FIG. To S106 and S107 to S114.

  As is clear from the above description, in the present embodiment, the lasers 30, 32, and 34 cooperate with each other to constitute an example of the “emitter” in the item (1), and the wavefront curvature modulator 22 is the same term. The signal processing circuit 39 constitutes an example of the “output unit” in the same section.

  Further, in the present embodiment, the portion of the signal processing circuit 39 that executes S4 to S6 in FIG. 7 and S112 to S114 in FIG. 9 constitutes an example of the “determination unit” in the above (2), The portion that executes S102 and S104 to S106 in FIG. 9 constitutes an example of the “generation unit” in the same section.

  Further, in the present embodiment, the received light amount detection device 97 and the portion of the signal processing circuit 39 that executes S1 to S3 in FIG. 7 and S107 to S110 in FIG. This constitutes an example of the “detection unit”. Further, in the signal processing circuit 39, the part that executes S1 to S3 in FIG. 7 constitutes an example of the “pre-display detection means” in the above section (4), and the part that executes S107 to S110 in FIG. This constitutes one example of the “displaying detection means” in item (5).

  Further, in the present embodiment, the line CCD sensor 98 constitutes an example of the “optical sensor” in the item (6), and the scanning device 24 constitutes an example of the “scanning unit” in the item (9). The plate 150 constitutes an example of the “light shielding portion” in the same section.

  Further, in the present embodiment, the converging lens 90 and the movable mirror 92 cooperate with each other to form an example of the “optical system” in the above section (14), and the line CCD sensor 98 is the “state sensor” in the same section. It constitutes an example.

  Next, a second embodiment of the present invention will be described. However, since this embodiment has many elements in common with the first embodiment, only the different elements will be described in detail, and the common elements will be described in detail using the same reference numerals or names. Description is omitted.

  In the first embodiment, in order to prevent the light emitted to detect the wavefront curvature from irradiating the observer's eye 10, the RSD exit port is closed with a cap before image display. To be done. Further, in order to prevent such unscheduled irradiation from being performed during image display, the wavefront curvature detection period is set to a portion corresponding to the non-image display area in the vertical scanning blanking period. And installing a light shielding plate 150 that covers the non-image display area.

  On the other hand, in the present embodiment, in order to prevent such unscheduled irradiation from being performed before and during image display, as shown in FIG. A shutter 210 is installed between the RSD outlet. In the present embodiment, the shutter 210 is installed between the wavefront curvature modulator 22 and the scanning device 24. The shutter 210 is a device that can be opened and closed instantaneously in order to selectively realize the state of covering the entire scanning region shown in FIG. 4 on the optical axis of the laser beam.

  The shutter 210 can be configured to include, for example, an entrance-side and an exit-side polarizer having a phase difference, and a phase controller disposed therebetween. The phase controller includes: For example, by utilizing the electro-optic effect or the magneto-optic effect, the polarization direction (phase) of light incident on the phase controller is changed, and the light incident on the incident-side polarizer passes through the output-side polarizer. It can be designed to switch between a state in which the shutter 210 is open (transmission allowable state) and a state in which the shutter 210 does not pass through, that is, a state in which the shutter 210 is closed (blocking state).

  As shown in FIG. 10, the shutter 210 is switched between a closed position and an open position by a wavefront curvature controller 158 electrically connected thereto.

  FIG. 11 conceptually shows the contents of the image display program in the present embodiment in a flowchart. Hereinafter, this image display program will be described. Since there are many steps common to the image display program shown in FIG. 9, the common steps will be briefly described.

  At each execution of the image display program shown in FIG. 11, S201 to S207 are executed in the same manner as S101 to S107 in FIG. Thereafter, in S <b> 208, a signal for closing the shutter 210 is output to the shutter 210.

  Subsequently, in S209, a depth signal for returning the movable mirror 92 to the origin position is output to the actuator driver 156 in the same manner as in S108 of FIG. 9, but in this S209, unlike S108, vertical scanning is performed. It is possible to perform light emission, wavefront modulation, and received light amount detection using a portion corresponding to the non-image display region and / or a portion corresponding to the image display region in the blanking period. This is because the entire scanning area is covered by the shutter 210 during the period of detecting the amount of received light.

  Thereafter, in S210, a test image is output as in S109 of FIG. Subsequently, in S211, the actual received light amount R2 is detected in the same manner as in S110 of FIG.

  Thereafter, in S212, the output of the test image is terminated, so that no laser beam is output from the light source including the lasers 30, 32, and 34, or the observer's eye 10 is not reached. To be output. As a result, the vertical scanning blanking is erased. Subsequently, in S <b> 213, a signal for opening the shutter 210 is output to the shutter 210.

  Thereafter, S214 through S217 are executed in the same manner as S112 through S115 in FIG. This completes one execution of the image display program.

  In addition, in this embodiment, the shutter 210 is also closed when the wavefront curvature is detected prior to image display. Therefore, unlike the first embodiment, it is not necessary to irradiate the observer's eyes 10 with unscheduled light even if the RSD exit port is not closed with a cap prior to image display.

  As is apparent from the above description, in the present embodiment, the shutter 210 constitutes an example of the “shutter” in the item (12), and the line CCD sensor 98 constitutes an example of the “light sensor” in the item. In the signal processing circuit 39, the portions that execute S207 to S211 and S213 in FIG. 11 constitute an example of the “shutdown detecting means” in the same term and the term (13), respectively.

  Next, a third embodiment of the present invention will be described. However, since this embodiment has many elements in common with the second embodiment, only different elements will be described in detail, and the common elements will be described in detail using the same reference numerals or names. Description is omitted.

  In the second embodiment, a line CCD sensor 98 is used to detect the wavefront curvature, as in the first embodiment. On the other hand, in the present embodiment, as shown in FIG. 12, another beam splitter 230 is arranged on the emission side of the beam splitter 94, so that the reference light is transmitted from the lasers 30, 32, and 34 to the beam splitter 94. In an optical path independent from the incident light on The reference light enters the received light amount detection unit 234.

  As shown in FIG. 13, the received light amount detection unit 234 includes a converging lens 240 into which reference light is incident, a pinhole member 244 in which a pinhole 242 into which outgoing light from the converging lens 240 is incident, and a pin And an optical sensor 246 that detects the amount of light emitted from the hole 242.

  As shown in FIG. 13, in the state where the parallel light is incident on the beam splitter 94 and the driving voltage for setting the wavefront curvature to 0 (making the radius of curvature infinite) is applied to the actuator 96, If the distance dc matches the normal value, that is, the initial value dc0, the reference light emitted from the beam splitter 230 becomes parallel light.

  If the parallel light is incident on the converging lens 240, the distance between the converging lens 240 and the pinhole 242 is set so as to focus on the pinhole 242. Light is received by the sensor 246.

  On the other hand, as shown in FIG. 14, when the distance dc does not coincide with the initial value dc0 due to manufacturing variations of the wavefront curvature modulator 22, disturbances such as temperature, the emitted light from the beam splitter 230 is non-parallel light ( In the example of FIG. When non-parallel light is incident on the converging lens 240, the light emitted from the converging lens 240 cannot be focused at the pinhole 242. Therefore, only a part of the light emitted from the converging lens 240 passes through the pinhole 242 and reaches the optical sensor 246. In this case, the amount of light received by the optical sensor 246 is less than when the reference light is parallel light, which is the same whether the reference light is diffuse light or convergent light.

  FIG. 15 is a graph showing the relationship between the wavefront curvature COW to be detected and the actual received light amount R of the optical sensor 246. The actual received light amount R coincides with the ideal received light amount R0 when the reference light is parallel light, and takes a value smaller than the ideal received light amount R10 when the reference light is diffused light. Even in the case of convergent light, the value is smaller than the ideal received light amount R0. However, when the reference light is diffused light, the actual received light amount R decreases as the wavefront curvature COW increases, whereas when the reference light is convergent light, the actual light reception amount R decreases as the wavefront curvature COW increases. The amount of received light R increases.

  Therefore, in the present embodiment, based on the difference ΔR between the actual received light amount R and the ideal received light amount R0 and the direction of the change gradient of the actual received light amount R with respect to the wavefront curvature COW (lower right or higher right), An offset value (including absolute value and sign) to be added to the depth signal is determined.

  As is clear from the above description, in the present embodiment, the received light amount detection unit 234 constitutes a part of an example of the “detection unit” in the item (3), and the optical sensor 246 includes the (6). It constitutes an example of “optical sensor” in the section.

  Further, in the present embodiment, the converging lens 90 and the movable mirror 92 cooperate with each other to constitute an example of the “optical system” in the above item (14), and the optical sensor 246 corresponds to the “state sensor” in the same term. It constitutes an example.

  Next, a fourth embodiment of the present invention will be described. However, since this embodiment has many elements in common with the first embodiment, only the different elements will be described in detail, and the common elements will be described in detail using the same reference numerals or names. Description is omitted.

  In the first embodiment, the wavefront curvature of the outgoing light from the wavefront curvature modulator 22 is detected using the outgoing light. On the other hand, in the present embodiment, paying attention to the fact that there is a certain relationship between the wavefront curvature and the distance dc between the converging lens 90 and the movable lens 92, the distance dc is detected, and the detected value is used as the detected value. Based on this, the aforementioned offset value is determined.

  Therefore, in this embodiment, as shown in FIG. 16, a distance detection device 270 is used instead of the received light amount detection device 97 in the first embodiment. This distance detection device 270 is configured to include a distance sensor 272 and a distance calculation unit 274, and a signal or data representing the distance calculated by the distance calculation unit 274 is supplied to the signal processing circuit 39.

  The distance sensor 272 includes a converging lens 90 or a member that moves integrally therewith and a movable mirror 92 or a member that moves integrally therewith in a direction parallel to the optical axis common to the converging lens 90 and the movable mirror 92. The separated distance is detected by various methods.

  An example of the distance sensor 272 is shown in FIG. In this example, the first element 282 of the distance sensor 272 is installed on the holder 280 that holds the convergent lens 90 in a fixed manner, while the second element 284 of the distance sensor 272 is installed on the movable mirror 92. Yes. One of the first element 282 and the second element 284 has a light emitting element and a light receiving element that emit a laser beam, and the other reflects the laser beam emitted from the light emitting element toward the light receiving element. It has a reflection mirror. In this example, the distance dc is detected based on the time that the laser beam makes one round trip between the first element 282 and the second element 284.

  As is apparent from the above description, in the present embodiment, the converging lens 90 and the movable mirror 92 cooperate with each other to provide an example of the “optical system” in the above item (14) and “ An example of “two components” is configured, and the converging lens 90 and the movable mirror 92 each configure an example of “component” in the item (17).

  Further, in the present embodiment, the distance sensor 272 constitutes an example of the “state sensor” in the item (14) and an example of the “distance sensor” in the item (15). On the other hand, detecting the distance dc between the converging lens 90 and the movable mirror 92 means detecting one position of the converging lens 90 and the movable mirror 92 relative to the other position. Is equivalent. Therefore, it can be considered that the distance sensor 272 constitutes an example of the “position sensor” in the item (16).

  Next, a fifth embodiment of the present invention will be described. However, since this embodiment has many elements in common with the first embodiment, only the different elements will be described in detail, and the common elements will be described in detail using the same reference numerals or names. Description is omitted.

  In the first embodiment, the wavefront curvature of the outgoing light from the wavefront curvature modulator 22 is detected using the outgoing light. On the other hand, in the present embodiment, focusing on the fact that there is a certain relationship between the wavefront curvature and the temperature of the wavefront curvature modulator 22, the temperature is detected, and the above-described offset is based on the detected value. The value of is determined.

  Therefore, in this embodiment, as shown in FIG. 18, a temperature detection device 300 is used instead of the received light amount detection device 97 in the first embodiment. The temperature detection device 300 is configured to include a temperature sensor 302 and a temperature calculation unit 304, and a signal or data representing the temperature calculated by the temperature calculation unit 304 is supplied to the signal processing circuit 39.

  The temperature sensor 302 detects the temperature of the components of the wavefront curvature modulator 22 whose thermal deformation affects the distance dc. The temperature sensor 302 detects the temperature by various methods such as a thermocouple and a thermistor.

  FIG. 19 shows an example of the temperature sensor 302. In this example, the wavefront curvature modulator 22 includes a holder 310 that fixedly holds the converging lens 90 and a frame 312 that supports the actuator 96 together. When the frame 312 is thermally deformed, the distance dc changes. Therefore, the temperature sensor 302 is installed on the frame 312.

  As is clear from the above description, in the present embodiment, the converging lens 90 and the movable mirror 92 cooperate with each other to form an example of the “optical system” in the above item (14), and further, these converging lenses 90 and the movable mirror 92 each constitute an example of the “component” in the above item (18).

  Furthermore, in the present embodiment, the temperature sensor 302 constitutes an example of the “state sensor” in the item (14) and an example of the “temperature sensor” in the item (18).

  As described above, some of the embodiments of the present invention have been described in detail with reference to the drawings. However, these are exemplifications, and are based on the knowledge of those skilled in the art including the aspects described in the section of [Disclosure of the Invention]. The present invention can be implemented in other forms with various modifications and improvements.

1 is a system diagram showing a retinal scanning display according to a first embodiment of the present invention. FIG. FIG. 2 is a side view showing a wavefront curvature modulator 22 in FIG. 1. It is a side view which shows the wave front curvature modulator 22 in FIG. 1 about the operation state different from FIG. It is a front view which shows the scanning area | region set to the retinal scanning display shown in FIG. 1, an image display area, and a non-image display area. It is a functional block diagram which shows the retinal scanning display shown in FIG. FIG. 2 is a block diagram conceptually showing the configuration of a signal processing circuit 39 in FIG. FIG. 7 is a flowchart conceptually showing the contents of a pre-display offset setting program in FIG. 6. It is a graph for demonstrating the principle by which a wavefront curvature is detected in the offset setting program before a display of FIG. 7 is a flowchart conceptually showing contents of an image display program in FIG. 6. It is a functional block diagram which shows the retinal scanning display according to 2nd Embodiment of this invention. 11 is a flowchart conceptually showing the contents of an image display program executed by a computer 190 of the signal processing circuit 39 in FIG. It is a functional block diagram which shows the retinal scanning display according to 3rd Embodiment of this invention. FIG. 13 is an optical path diagram showing a wavefront curvature modulator 22 in FIG. 12 and a side view showing a received light amount detector 170. FIG. 13 is an optical path diagram showing a wavefront curvature modulator 22 in FIG. 12 and a side view showing a received light amount detector 170. It is a graph which shows the relationship between wavefront curvature COW and the actual light reception amount R1, R2 in the said 3rd Embodiment. It is a functional block diagram which shows the retinal scanning display according to 4th Embodiment of this invention. FIG. 17 is a side view showing the wavefront curvature modulator 22 and the distance sensor 272 in FIG. 16. It is a functional block diagram which shows the retinal scanning display according to 5th Embodiment of this invention. FIG. 17 is a side view showing the wavefront curvature modulator 22 and the temperature sensor 302 in FIG. 16.

Explanation of symbols

DESCRIPTION OF SYMBOLS 22 Wavefront curvature modulator 24 Scanning device 30,32,34 Laser 39 Signal processing circuit 90 Converging lens 92 Movable mirror 96 Actuator 97 Light reception amount detection device 98 Line CCD sensor 150 Light-shielding plate 154 Image signal control part 158 Wavefront curvature control part 170 Light reception Quantity detection unit 210 Shutter 246 Optical sensor 272 Distance sensor 302 Temperature sensor

Claims (13)

An image display device that displays an image to an observer so that the depth of the image is expressed,
An emission unit that emits light based on a luminance signal among video signals supplied from the outside to display the image ;
A modulation unit that modulates the wavefront curvature of light emitted from the emission unit, thereby expressing the depth of the image, using a piezoelectric element as a drive source;
A scanning unit that two-dimensionally scans the light emitted from the modulation unit, the scanned light is projected onto the retina of the viewer, and the image is displayed to the viewer;
A detection unit for detecting a real wavefront curvature-related amount that is a wavefront curvature-related amount related to the wavefront curvature of the light emitted from the modulation unit and that is an actual value of an amount that changes according to the change of the wavefront curvature;
Based on the relationship between the detected actual wavefront curvature-related quantity and the ideal value of the wavefront curvature-related quantity, a correction value for the original depth signal, which is a depth signal of the video signal, is determined, and the determined correction A determining unit that generates a corrected depth signal based on the value and outputs the generated corrected depth signal to the modulation unit;
Including
The modulation unit modulates the wavefront curvature based on the corrected depth signal output from the determination unit,
The detection unit detects the real wavefront curvature related amount during execution of a series of image display by the image display device,
The determination unit generates the corrected depth signal based on the actual wavefront curvature-related amount detected by the detection unit during execution of a series of image displays by the image display device, and outputs the corrected depth signal to the modulation unit apparatus. The detection unit is based on the relationship between the wavefront curvature and the light receiving area that the light receiving area of the emitted light is smaller as the wavefront curvature of the emitted light from the modulating unit is smaller. The image display device according to claim 1, further comprising: an optical sensor that detects the real wavefront curvature-related amount by detecting a light receiving area . The detection unit detects the real wavefront curvature related amount by the optical sensor in a light detection state where the emission unit emits light in a set state and a set depth signal is output to the modulation unit. the image display device according to some claim 2. The detection unit emits light in a set state regardless of an image to be displayed during execution of a series of image displays by the image display device, and a set depth signal is output to the modulation unit. The image display device according to claim 2 , wherein the real wavefront curvature-related amount is detected by the optical sensor in an output light detection state . The scanning unit can scan light not only in the image display area set for the observer, but also in the non-image display area set outside thereof,
The image display device further includes:
A light-shielding unit that is provided between the modulator and the observer, and allows light directed from the modulator to the image display region to pass therethrough, and blocks light directed to the non-image display region;
The detection unit emits light in a set state during execution of a series of image displays by the image display device, and a set depth signal is output to the modulation unit, and from the modulation unit The state in which the emitted light is scanned in the direction toward the non-image display region by the scanning unit is set as the light detection state, and the real wavefront curvature related amount is detected by the optical sensor in the light detection state. The image display device according to claim 4 . The image display apparatus according to claim 5 , wherein the detection unit is configured to detect the actual wavefront curvature-related amount by the optical sensor during a blanking period in scanning by the scanning unit. The scanning unit performs horizontal scanning for scanning light emitted from the emitting unit in a horizontal direction and vertical scanning for scanning in a vertical direction.
The image display apparatus according to claim 6 , wherein the detection unit is configured to detect the actual wavefront curvature-related amount by the optical sensor during a blanking period in the vertical scanning . Further, the transmission unit is provided between the modulation unit and the observer, and switches between a permissible transmission state that allows light emitted from the modulation unit to pass therethrough and a blocking state that blocks light emitted from the modulation unit. Including a shutter,
The detector is
(A) an optical sensor for detecting the real wavefront curvature-related amount by detecting light emitted from the modulation unit;
(B) In a light detection state in which the emission unit emits light in a set state, a set depth signal is output to the modulation unit, and light emitted from the modulation unit is blocked by the shutter, A detecting means during shut-off for detecting the real wavefront curvature related quantity by an optical sensor;
The image display device according to claim 1 , comprising: The modulation unit includes an optical system that changes the actual value of the wavefront curvature when the state of the modulation unit changes,
The image display device according to claim 1, wherein the detection unit includes a state sensor that detects a state of the optical system . The optical system includes two components that cause a change in the actual value of the wavefront curvature when the mutual distance changes;
The image display device according to claim 1, wherein the detection unit includes a distance sensor that detects a distance between the two components . The two components include a lens on which the light emitted from the emitting portion is incident and a mirror that reflects the light emitted from the lens toward the lens, and the reflected light from the mirror is applied to the lens. The image display device according to claim 10 , wherein a wavefront curvature of light that is incident and exits from the lens changes according to a distance between the lens and the mirror . The optical system includes a component that causes a change in the actual value of the wavefront curvature when the position of the optical system changes;
The image display device according to claim 1, wherein the detection unit includes a position sensor that detects a position of the component. The optical system includes components that cause a change in the actual value of the wavefront curvature when its temperature changes;
The image display device according to claim 1, wherein the detection unit includes a temperature sensor that detects at least one of a temperature of the component and a temperature around the component.

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