JP5932945B2 - projector - Google Patents

Description

  The present invention relates to a projector.

  Conventionally, a laser projector is known as a projector that projects an image input from the outside by laser light. Since this projector is used by projecting an image to a position that is generally distant, a pointer that reaches from the position of the user to the position of the image in order for the user to indicate a desired point from the projected image. In addition, it is necessary to use a laser pointer that performs laser irradiation on the image. In addition, when inputting an image from another information device connected to the projector, the user has designated a desired point via an input device such as a touch panel or a mouse included in the information device.

  However, depending on the environment in which the projector is installed, it may be burdensome for the user to indicate a desired point using the pointing device such as the pointer or the laser pointer, or the input device such as the touch panel or the mouse. Often exists.

Here, for example, in a position measurement device that measures the position of a light source that emits diffused light on at least a two-dimensional plane, the amount of diffused light received from the light source in a light receiving plane region provided on a plurality of planes that intersect each other When a light source is arranged on a straight line at an angle of 45 degrees around the central axis of two light receiving plane areas or two light receiving plane area groups in the measurement unit, There is known an adjustment means that adjusts the gain of the received light amount so that the received light amounts in the planar region or the two light receiving planar region groups are substantially the same (see, for example, Patent Document 1).
In the invention described in Patent Document 1, the planar position of the light source is derived from a light amount in each of the X and Y directions detected from two light receiving elements arranged in orthogonal directions through a predetermined derivation formula by a calculation unit. Therefore, the plane position of the light source can be calculated more accurately by adjusting the gains of the two light receiving elements by the adjusting means to suppress variations in the light amounts in the X and Y directions.
Therefore, if the projector can be provided with the position measuring device described in Patent Document 1 so that the pointing position can be projected, the pointing device such as a pointing rod or a laser pointer, or an input device such as a touch panel or a mouse can be used. There is no need to indicate the point to be.

JP 2002-014763 A

However, according to the invention described in Patent Document 1, it is necessary to derive the coordinate value through a complicated calculation process by the calculation unit based on the received light amount, and thus there is a concern about the processing load of the CPU and the like related to position detection. Is done.
Further, depending on the invention described in Patent Document 1, the identification accuracy itself of an external obstacle (for example, the tip of a pointer, a fingertip, etc.) for indicating a point becomes a problem. In other words, the attenuation rate of light intensity and the S / N (Signal to Noise) ratio vary depending on the position where the external obstacle exists, so the identification accuracy of the external obstacle varies depending on the position, and the external obstacle There is a risk of misidentification.

  An object of the present invention is to provide a projector that can easily detect the position of an external obstacle and has high identification accuracy of the external obstacle.

In order to solve the above-described problem, in a projector according to a first aspect of the present invention, in a projector, a light source that outputs laser light, scanning means that scans the laser light, and the laser light that is scanned by the scanning means A beam splitter that divides in one direction and a second direction, a light receiving sensor that receives the laser light reflected by an external obstacle in a region of the laser light irradiated on the projection surface in the first direction, A scanning position by a scanning means, and a calculating means for calculating the position of the external obstacle based on light reception by the light receiving sensor, wherein the first direction laser light passes through the beam splitter. The light and the second laser light not passing through the beam splitter are irradiated.

  According to a second aspect of the present invention, in the projector according to the first aspect, the scanning by the scanning unit is based on a horizontal synchronization signal and a pixel clock signal.

  According to a third aspect of the present invention, in the projector according to the first or second aspect, the second laser light is irradiated such that at least a part of the second laser light is adjacent to the first laser light.

According to a fourth aspect of the present invention, in the projector according to any one of the first to third aspects, the first laser light has a quadrangular shape with respect to the projection surface in the first direction. Irradiated.

According to a fifth aspect of the present invention, in the projector according to the fourth aspect , the second laser light is irradiated such that at least a part of the second laser beam is adjacent to one side of the quadrilateral farthest from the light receiving sensor. It is characterized by.

According to a sixth aspect of the present invention, in the projector according to any one of the first to fifth aspects, an amplification unit that amplifies a light reception amount of the light reception sensor and an amplification amount are determined based on the calculated position. And a determining means.

According to a seventh aspect of the present invention, in the projector according to the sixth aspect , the determining unit determines an amount of amplification in the amplifying unit based on a distance between the calculated position and the light receiving sensor. Features.

According to an eighth aspect of the present invention, in the projector according to the seventh aspect , the amplification amount increases as the distance between the calculated position and the light receiving sensor increases.

According to the present invention, the determination unit specifies the reflection position of the reflected light received by the light receiving sensor, reflects the reflected light at the specified reflection position, and increases the amount of amplification of the reflected light received by the light receiving sensor. Since it is configured to be determined, it is possible to adjust the amount of amplification in consideration of the influence of the attenuation factor of the light intensity of the reflected light according to the reflection position, so an external obstacle due to the reflection position Variation in identification accuracy can be suppressed. Further, since the calculating means can easily calculate the position information of the external obstacle based on the timing determined by the determining means as the external obstacle and the horizontal synchronization signal and the pixel clock signal, the position of the external obstacle can be detected. No special configuration is needed for. Further, the calculation of the position information is not performed based on the amount of reflected light received by the light receiving sensor, and thus does not require complicated calculations.
Therefore, the present invention can be said to be a projector that can easily detect the position of an external obstacle and has high identification accuracy of the external obstacle.

It is an external view which illustrates the state in which the projector which concerns on this invention was installed. FIG. 3 is a block diagram illustrating a main configuration of a projector according to the invention. It is a figure for demonstrating the projection surface of the laser beam which concerns on this invention. It is a figure for demonstrating the synchronizing signal (horizontal synchronizing signal and pixel clock signal) which concerns on this invention. It is a figure for demonstrating the structure of the projection part which concerns on this invention, and the state in which the laser beam was projected by the projection part. It is a figure which illustrates the intensity distribution on the projection surface of the reflected light received by the light receiving sensor according to the present invention, and the analog / digital gain at each position. FIG. ) Indicates the intensity distribution in the X direction. It is a figure which illustrates the gain data concerning the present invention. It is a figure for demonstrating another gain data based on this invention, (A) shows the area division on a projection surface, (B) illustrates another gain data. It is a figure which illustrates intensity distribution of the amplified reflected light on a certain scanning line. It is a flowchart for demonstrating the gain adjustment process by the projector which concerns on this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The scope of the invention is not limited to the illustrated example.
In the following description, the left-right direction of the projector 100 in FIG. 1 is the X direction, the front-rear direction is the Y direction, and the height direction is the Z direction.

For example, as shown in FIG. 1, the projector 100 is installed on a table 120, and a laser beam (second laser beam) emitted toward the screen 130 is used for display and the like used by the projection unit 380. It is a laser projector projected as an image 132A.
Further, in the projector 100, the laser beam (first laser beam) separated by the projection unit 380 is the same as the image 132A so that the user of the projector 100 can refer to the upper surface of the table 120. 122A is projected (the size of the image 122A is generally smaller than the size of the image 132A). Here, the image 122A also includes an image 122F for the user to edit the image 132A by operating the external obstacle 10 such as a stick or a pen. And the reflected light from the said external obstruction 10 is detected by the light reception sensor 400, and it is comprised so that the external obstruction 10 may be identified.

  Next, for example, as illustrated in FIG. 2, the projector 100 includes a front-end FPGA 310 (Field Programmable Gate Array), a laser emission unit 350, a projection unit 380, an operation panel 330, a back-end block 340, The video RAM 345, the light receiving sensor 400, the amplification unit 410, the conversion unit 420, and the storage unit 344 are configured.

  The FPGA 310 is an LSI (Large Scale Integration) that can be programmed including, for example, a timing controller 311, a data controller 312, a bit data converter 313, and a data / gradation converter 314, and a back-end block 340. At the same time, display control of the image signal temporarily stored in the video RAM 345 is performed.

  The timing controller 311 reads out an image signal temporarily stored in the video RAM 345 via the data controller 312 based on a command sent from the CPU 341 included in the back-end block 340. The timing controller 311 acquires a synchronization signal (including a horizontal synchronization signal (HSYNC), a pixel clock signal (PCLK), and the like) included in the image signal. Further, the timing controller 311 generates a command for controlling the emission / driving timing of a laser emission unit 350 and a drive motor 374, which will be described later, based on the synchronization signal, and the command is transmitted to the bit data converter 313, the drive driver 373. Send to each.

The data controller 312 sends the image signal read from the video RAM 345 to the bit data converter 313.
Based on a command from the timing controller 311, the bit data converter 313 converts the image signal sent from the data controller 312 into data suitable for a format for projection by laser light, and the converted image signal is converted into data. / Grayscale converter 314.

  The data / gradation converter 314 converts the data output from the bit data converter 313 into color gradations for display as three colors of R (Red), G (Green), and B (Blue). The converted data are sent to the laser emitting unit 350.

  The laser emitting unit 350 includes, for example, LDs 361 and 362 (laser light sources), a laser control circuit 351, a polarization beam splitter 363, a laser detector 370, a lens 371, a scanner mirror 372 (scanning unit), and a drive driver. 373, the drive motor 374, the half mirror 375, the mirror detector 376, and the adjustment part 377 are comprised.

An LD 361 (Laser Diode) is a diode that emits green laser light, and an LD 362 is a diode that emits red and blue laser light, and each is controlled by a laser control circuit 351.
Note that the LD 362 according to the present embodiment is configured integrally with the LD that emits red laser light and the LD that emits blue laser light, but may be configured separately.

  The laser control circuit 351 controls the emission amount / timing of the LDs 361 and 362 based on a signal sent from the data / gradation converter 314. Further, the laser control circuit 351 detects the emission state of the laser beam from the output amount of the laser beam detected by a laser detector 370 described later, and performs emission control of the LDs 361 and 362 based on the emission state.

  The polarization beam splitter 363 is an optical member that is disposed on the optical path of the laser light emitted from the LD 361 and separates the incident laser light into P-polarized light and S-polarized light. The polarization beam splitter 363 transmits part of the green laser light emitted from the LD 361 toward the lens 371 and reflects the rest toward the laser detector 370. On the other hand, the polarization beam splitter 363 transmits part of the red and blue laser beams emitted from the LD 362 toward the laser detector 370 and reflects the rest toward the lens 371.

The laser detector 370 is, for example, a sensor that detects the output amount of laser light, and is disposed on the optical path of the laser light emitted from the LD 362.
The lens 371 condenses the laser light that has passed through the polarization beam splitter 363.

The scanner mirror 372 is, for example, a galvano mirror that can be rotated independently in two axial directions by applying a driving force by a driving motor 374 described later, and by adjusting the mirror tilt angle by the rotation, The reflection direction of the incident light can be adjusted.
Therefore, for example, as shown on the projection surface 123 of the laser beam (first laser beam) formed on the table 120 in FIG. 3, the reflection direction of the laser beam transmitted through the lens 371 is sequentially adjusted by the scanner mirror 372. This makes it possible to scan with laser light.
Here, FIG. 3 shows that the scanning position of the laser beam by the scanner mirror 372 on the projection surface 123 is P (1), P (2) according to the pixel clock signal and horizontal synchronization signal acquired by the timing controller 311. ,..., P (k), P (k + 1),..., P (2k),. The pixel clock signal (PCLK) and the horizontal synchronization signal (HSYNC) are, for example, signals each having a pulse waveform as shown in FIG. 4, and the time ΔT1 is the time for drawing one pixel, and the time ΔT2 is This shows the time until one scanning line is switched.
That is, during the time ΔT1 of the pixel clock signal, the scanner mirror 372 tilts in the X direction, and the scanning position of the laser beam shown in FIG. 3 is shifted in the X direction (for example, from P (1) to P (2)). Change). Then, when the scanning in the X direction is repeated and the scanning position reaches the X direction end (for example, P (k)) of the projection surface 123, the horizontal synchronization signal time ΔT2 has passed and the horizontal synchronization signal has passed. Is detected. During the time ΔT2, the scanner mirror 372 is tilted in the Y direction, and the scanning position of the laser beam shown in FIG. 3 is shifted in the Y direction (for example, changes from P (k) to P (k + 1)).
Therefore, the scanner mirror 372 repeats the above scanning based on the pixel clock signal and the horizontal synchronization signal, and image projection for one frame is completed when the scanning is completed over the entire projection surface 123.

For example, the drive driver 373 controls the scanning of the laser beam by the scanner mirror 372 by giving a pulse signal corresponding to the drive frequency to the drive motor 374 in accordance with a command transmitted from the timing controller 311.
The drive motor 374 is, for example, two pulse motors connected to each of the two axes of the scanner mirror 372, and each is driven based on a drive frequency (resonance frequency) instructed by a drive driver 373, which will be described later. The 372 is configured to rotate by a predetermined angle.

The half mirror 375 transmits a part of the laser light reflected by the scanner mirror 372 toward the projection unit 380 and reflects the rest toward the mirror detector 376.
The mirror detector 376 is, for example, a tilt angle detector that receives laser light reflected by the half mirror 375 and detects the tilt angle (touch angle) of the scanner mirror 372 in the biaxial direction. The tilt angle detected by the mirror detector 376 is input to the adjustment unit 377 as an analog electric signal.
The adjustment unit 377 includes, for example, an arithmetic unit for arithmetic operation, a comparator, an amplifier for analog signal amplification, an A / D converter, and the like, which are not illustrated, and are input from the mirror detector 376. The analog electrical signal related to the tilt angle of the scanner mirror 372 is adjusted to a desired value through amplification, arithmetic operation, comparison, etc., converted into a digital signal, and transmitted to the CPU 341.
In other words, the resonance frequency of the scanner mirror 372 varies depending on the installation environment (for example, temperature, humidity, atmospheric pressure, etc.), and there is a possibility that the scanning position of the laser beam is displaced. The tilt angle of the mirror 372 is detected and transmitted to the CPU 341 so that the CPU 341 and the timing controller 311 can sequentially adjust the drive frequency by the drive driver 373.

  For example, as shown in FIG. 5, the projection unit 380 includes a collimator lens 381, a spatial light modulator 382, a beam splitter 383, and magnifying lenses 384 and 385, and is emitted from the laser emission unit 350. The laser light (scanned by the scanner mirror 372) is projected onto the screen 130 and the table 120.

The collimator lens 381 collimates the laser beam scanned by the scanner mirror 372.
The spatial light modulator 382 is, for example, a light valve that transmits only light in a predetermined polarization direction, and modulates the transmittance of the laser light that has been collimated through the collimator lens 381 according to the image signal. The light is emitted toward the beam splitter 383.

The beam splitter 383 is arranged so that only a part of the laser light emitted from the spatial light modulator 382 is incident, and transmits the incident laser light in the direction of the table 120 (first direction). And the second laser beam reflected in the screen 130 direction (second direction).
Accordingly, a part of the laser light passing through the optical path where the beam splitter 383 is disposed is transmitted through the beam splitter 383 and projected toward the table 120, and the remaining part is reflected (refracted) by the beam splitter 383. And projected in the direction of the screen 130. On the other hand, the laser light passing through the optical path where the beam splitter 383 is not arranged is projected only in the direction of the table 120 without being reflected (refracted) by the beam splitter 383.
That is, the CPU 341 displays the dedicated image 122F for editing the image 132A so that the laser beam for displaying the presentation image 132A passes through the optical path where the beam splitter 383 is arranged. By controlling the FPGA 310 and the laser emitting unit 350 so that the laser beam passes through the optical path where the beam splitter 383 is not disposed, the image 132A and the image 122A are projected on the screen 130 and 120, respectively. It becomes possible to do.
Note that the dedicated image 122F may be, for example, a comment that corresponds to the image 132A currently being projected. Thus, only the user can refer to the dedicated image 122F during the display of the image 132A. That is, even if the user does not remember a comment or the like to be spoken during the display of the image 132A, the presentation can proceed smoothly.

The magnifying lens 384 is disposed on the downstream side of the beam splitter 383 in the screen 130 direction, and magnifies the laser beam reflected by the beam splitter 383. The magnifying lens 385 is arranged on the downstream side of the beam splitter 383 in the table 120 direction, and magnifies the laser light transmitted through the beam splitter 383 and the laser light passing through the optical path where the beam splitter 383 is not arranged.
Then, the laser light magnified by the magnifying lenses 384 and 385 is applied to the screen 130 and the table 120 through a mirror and a lens (not shown).

  The operation panel 330 is provided, for example, on the surface or side surface of the casing of the projector 100, and includes a display device (not shown) for displaying operation details, buttons for the user to perform input operations on the projector 100, And a switch (not shown). Then, when an operation by the user is executed, the operation panel 330 transmits a signal corresponding to the operation to the CPU 341.

  The back end block 340 is a back end portion of the projector 100 configured to include a CPU 341, a video I / F 342, and an external I / F 343, for example.

The CPU 341 controls the overall operation of the projector 100 by reading various processing programs stored in the storage unit 344, executing the programs, and transmitting output signals to the respective units.
Further, the CPU 341 controls projection of video based on an image signal input to the projector 100 via the video I / F 342 and the external I / F 343 based on a signal transmitted from the operation panel 330. That is, the CPU 341 communicates with the timing controller 311 of the FPGA 310 to control the display of video based on the image signal temporarily stored in the video RAM 345.

  The video I / F 342 is an interface for connecting to an image output device 150 such as a PC (Personal Computer), for example, and inputting an image signal output from the image output device 150.

  The external I / F 343 is an interface for an external storage medium to which a memory card 151 such as a USB (Universal Serial Bus) flash memory or an SD memory card can be mounted, for example, and reads an image signal stored in the memory card 151. Input to the projector 100 is possible.

  The video RAM 345 temporarily stores an image signal input via the video I / F 342 or the external I / F 343. The image signal is configured to be read from the timing controller 311 (data controller 312) when display control by the FPGA 310 is performed.

The light receiving sensor 400 includes, for example, a light receiving element such as a photodiode, a lens, and the like, although not shown, receives the reflected light from the projection surface 123 and receives the intensity of the reflected light (for example, incident light). The amount of current flowing in the photodiode in accordance with the sensor). Then, the detected intensity of the reflected light is transmitted to the amplification unit 410 as an analog light intensity signal.
The light receiving sensor 400 receives (senses) reflected light every time the scanner mirror 372 scans (ie, draws one pixel), that is, at the timing when the time ΔT1 of PCLK shown in FIG. 4 elapses. ) Is configured as follows.

  The amplifying unit 410 is, for example, a variable gain amplifier for analog signals that amplifies an input analog light intensity signal with an arbitrary gain. More specifically, when an analog light intensity signal corresponding to the intensity of reflected light is input from the light receiving sensor 400, the amplifying unit 410 is based on a signal transmitted from the CPU 341 by executing a gain adjustment program 344b described later. The gain can be changed, and the input analog light intensity signal can be amplified by the changed gain.

  The conversion unit 420 is, for example, a DSP (Digital Signal Processor) that can perform signal processing such as A / D conversion, filtering, and compression / decompression of input data, and converts the input analog light intensity signal into a digital light intensity signal. Convert. Therefore, the converter 420 converts the analog light intensity signal corresponding to the intensity of the reflected light amplified by the amplifier 410 into a digital light intensity signal, and transmits the converted digital light intensity signal to the CPU 341.

  The storage unit 344 is, for example, a nonvolatile memory, and includes a storage area for storing a program executed by the CPU 341 and various data necessary for executing the program. The storage area includes, for example, an amplification program 344a (amplification unit, digital amplification unit), gain adjustment program 344b (determination unit), gain data 344c, determination program 344d (determination unit), calculation program 344e (calculation unit), update A program 344f (update means) and the like are stored.

  The amplification program 344a gives the CPU 341 a function of amplifying a digital light intensity signal corresponding to the intensity of the reflected light converted into a digital signal by the conversion unit 420 with a digital gain determined by executing a gain adjustment program 344b described later. It is a program to be executed.

  The gain adjustment program 344b is a program that causes the CPU 341 to execute a function of determining an amplification amount (gain) of an analog / digital light intensity signal corresponding to the intensity of reflected light received by the light receiving sensor 400.

Specifically, when the CPU 341 executes the gain adjustment program 344b, first, the reflection position of the reflected light received by the light receiving sensor 400 is specified.
That is, as described above, since the light receiving sensor 400 receives light each time the scanner mirror 372 performs scanning, the elapsed time from when the light receiving sensor 400 starts sensing until the reflected light is received, and FIG. By calculating the scanning position of the scanner mirror 372 at the elapsed time based on the relationship between the indicated PCLK time ΔT1 and the HSYNC time ΔT2, the position (reflection position) at which the light receiving sensor 400 receives the reflected light is specified. I can do it.

Next, the CPU 341 determines the amount of amplification of the intensity of the reflected light from the X coordinate and Y coordinate of the identified reflection position according to FIGS. 6 (A) and 6 (B).
Here, the solid lines in FIGS. 6A and 6B indicate the Y values when the reflected light reflected by the light receiving sensor 400 at the respective reflection positions on the projection surface 123 is received by the light receiving sensor 400. It is a line (that is, the distribution of the light receiving sensitivity of the light receiving sensor 400 at each reflection position) schematically showing the intensity at the coordinates and the X coordinate. Note that the points Y0, Y1, X0, and X1 in FIGS. 6A and 6B correspond to the Y and X coordinates of the end points of the projection plane 123 in FIG. 3, and the point X2 is a position between X0 and X1. It is a point and indicates the X coordinate of the light receiving sensor 400.

First, as indicated by the solid line in FIG. 6A, as the distance in the Y direction between the sensing position in FIG. 3 and the light receiving sensor 400 increases (as the sensing position moves away from the light receiving sensor 400), the light intensity attenuation rate increases. Since it increases, the intensity of reflected light (light reception sensitivity) decreases.
Therefore, for example, as indicated by the dotted line in FIG. 6A, the analog gain of the amplification unit 410 is set to a larger value every time the Y-direction distance between the reflection position and the light receiving sensor 400 increases by a predetermined amount. The light receiving sensitivity can be maintained at a predetermined value or more regardless of the position in the Y direction. Further, by amplifying the intensity of the reflected light amplified by the analog gain with a digital gain as shown by a broken line in FIG. 6A, reflection is performed as shown by a one-dot chain line in FIG. 6A. The intensity of the light is corrected to a linear change in inclination, resulting in a straight line parallel to the Y axis. That is, by determining the digital gain of the amplification program 344a to a value as shown by the broken line in FIG. 6A, the light receiving sensitivity can be made uniform regardless of the position in the Y direction.

  On the other hand, as indicated by the solid line in FIG. 6B, the sensing position in FIG. 3 moves away from the position where the X direction distance from the light receiving sensor 400 is the closest in the X direction (that is, the X coordinate of the reflection position changes from X2). Since the attenuation rate of the light intensity increases (as it changes to X0 or X1), the intensity of the reflected light (light reception sensitivity) decreases. Therefore, for example, as indicated by a broken line in FIG. 6B, a digital gain represented by a curve symmetric with respect to an axis passing through the half value of the peak value of the solid line in FIG. By determining the gain, the light receiving sensitivity can be made uniform regardless of the position in the X direction.

  Therefore, for example, as shown in FIG. 7, in order to uniformize the light receiving sensitivity at each reflection position, an analog / digital gain is determined for each position on the projection surface 123, and stored in advance as gain data 344c. Stored in 344. Then, when the CPU 341 executes the gain adjustment program 344b and specifies the reflection position of the reflected light received by the light receiving sensor 400, the analog gain and the digital gain corresponding to the reflection position are extracted from the gain data 344c, respectively. The light receiving sensitivity at the reflection position can be made uniform.

  Further, for example, as shown in FIGS. 8A and 8B, the gain data 344c is obtained for each area (for example, areas A1, B1, A2, B2) in which the projection plane 123 is divided into a plurality of parts based on the reflection position. ,..., Etc.) may be stored analog / digital gain. That is, as described above, when an analog / digital gain is determined for each reflection position and amplification based on the gain is performed by executing the amplification unit 410 and the amplification program 344a, the uniformity of the light receiving sensitivity is accurately realized. However, since it is necessary to change the gain each time the reflected light is received by the light receiving sensor 400 (for each reflection position), there is a concern about the processing load on the CPU 341. For this reason, the projection plane 123 is divided into areas so that the light receiving sensitivity at each reflection position is equal to or higher than a predetermined value, and the analog / digital gain is set to a value suitable for each area. Since it is not necessary to change the gain every time, an increase in the processing load on the CPU 341 can be suppressed, and the light receiving sensitivity at each reflection position can be ensured.

The determination program 344d is a program that causes the CPU 341 to execute a function of determining the external obstacle 10 when the intensity of the reflected light amplified by the execution of the amplification unit 410 and the amplification program 344a exceeds a predetermined threshold.
Specifically, for example, scanning with the projection surface 123 detected by the light receiving sensor 400 and amplified by the amplification unit 410 and the amplification program 344a based on the amplification amount determined by the execution of the gain adjustment program 344b. Suppose that the intensity of the reflected light at each reflection position on the line (for example, the scanning line L passing through the external obstacle 10 in FIG. 3) has a distribution as shown in FIG. 9 (each point in FIG. Corresponding to the reflection position). In this case, the CPU 341 executes the determination program 344d, and the light receiving sensor 400 detects the intensity of the reflected light by comparing a predetermined threshold value of the reflected light intensity with the intensity of the reflected light at each reflection position. It is determined every time that the threshold value is exceeded for the first time (that is, when the intensity of the point Q1 in FIG. 9 is detected by the light receiving sensor 400).

The calculation program 344e causes the CPU 341 to execute a function of calculating the position information of the external obstacle 10 based on the timing determined as the external obstacle 10 by the execution of the determination program 344d and the horizontal synchronization signal and the pixel clock signal. It is a program.
Specifically, for example, when the CPU 341 executes the calculation program 344e, the light receiving sensor 400 is based on the timing at which the intensity of reflected light detected by the light receiving sensor 400 first exceeds the threshold due to the execution of the determination program 344d. By calculating the scanning position of the scanner mirror 372 at the elapsed time from the relationship between the elapsed time from the start of sensing to the above timing and the time ΔT1 of PCLK and the time ΔT2 of HSYNC shown in FIG. The position (position information) of the external obstacle 10 can be specified.

The update program 344f obtains a gain for each predetermined period (for example, every time an image signal for several frames is projected) based on the peak value of the intensity of the reflected light amplified by the execution of the amplification unit 410 and the amplification program 344a. This is a program for causing the CPU 341 to execute a function of updating the gain determined by the execution of the adjustment program 344b.
Specifically, when the CPU 341 executes the update program 344f, for example, as shown in FIG. 9, the scanning line including the position determined to be the external obstacle 10 by the execution of the determination program 344d (for example, FIG. 9, the intensity of the reflected light at each reflection position on the scanning line L) of FIG. Then, the CPU 341 extracts the peak value of the intensity (for example, the intensity of the point Q2 in FIG. 9), and sets the difference amount between the peak value and the intensity peak value (target value) stored in the storage unit 344 in advance. Based on this, a new analog / digital gain is calculated, and the gain of the gain data 344c is updated based on the calculated value. The intensity peak value stored in the storage unit 344 is updated with the extracted peak value after the CPU 341 executes the update program 344f.
That is, the gain of the gain data 344c is not set to a fixed value, and the gain before the change (the peak value of the intensity of the reflected light amplified by the reflection) is reflected to determine a new gain for each predetermined period. It is possible to improve the light receiving sensitivity due to.

"Gain adjustment process"
Next, the flow of gain adjustment processing performed in the projector 100 of the present embodiment will be described with reference to the flowchart of FIG.

First, the scanner mirror 372 scans the projection surface 123, and the light receiving sensor 400 performs sensing (step S1).
Next, the CPU 341 executes the gain adjustment program 344b, specifies the position (reflection position) received by the light receiving sensor 400 in step S1, refers to the gain data 344c, and the analog gain of the amplifying unit 410 at the position. The digital gain of the amplification program 344a is adjusted (step S2).

  Next, based on the analog / digital gain adjusted in step S2, the amplification unit 410 amplifies the analog light intensity signal of the reflected light detected by the light receiving sensor 400, the CPU 341 executes the amplification program 344a, The digital light intensity signal obtained by digitally converting the analog light intensity signal through the converter 420 is amplified, and the intensity of the reflected light is detected (step S3).

  Next, the CPU 341 executes the determination program 344d and determines whether or not the intensity of the reflected light detected in step S3 exceeds a threshold value (step S4).

  If the CPU 341 determines in step S4 that the threshold is exceeded (determined to be the external obstacle 10) (step S4; Yes), the CPU 341 executes the calculation program 344e to calculate the position information of the external obstacle 10. (Step S5).

On the other hand, if the CPU 341 determines in step S4 that the threshold value has not been exceeded (step S4; No), whether or not scanning at all positions on the projection surface 123 has been completed by the scanner mirror 372 (light receiving sensor). 400 determines whether or not the reflected light at all the reflection positions has been received (step S6).
If the CPU 341 determines that the scanning is finished in step S6 (step S6; Yes), the CPU 341 executes the process of step S7. If the CPU 341 determines that the scanning is not finished (step S6; No), the step The processes after S1 are repeated.

Next, the CPU 341 determines whether it is time to update the gain of the gain data 344c (step S7).
If the CPU 341 determines that it is time to update in step S7 (step S7; Yes), the CPU 341 executes the update program 344f to update the gain of the gain data 344c (step S8), and ends this processing. .
On the other hand, when the CPU 341 determines that it is not the timing to update in step S7 (step S7; No), the CPU 341 ends this processing without updating the gain of the gain data 344c.

As described above, the projector 100 according to the present invention includes the LD 361 and 362 for supplying laser light according to the input image signal, the scanner mirror 372 for scanning the laser light supplied from the LD 361 and 362, and the scanner mirror 372. A beam splitter 383 that divides and outputs the scanned laser light into a first direction and a second direction, and receives reflected light of the first laser light that is output in the first direction by the beam splitter 383. Based on the light receiving sensor 400, the horizontal synchronization signal of the image signal, and the pixel clock signal, the reflection position of the reflected light received by the light receiving sensor 400 is specified, and reflected at the specified reflection position, and is received by the light receiving sensor 400. Gain adjustment program 344b for determining the gain of the intensity of the reflected light received, and gain adjustment program 344b The amplification unit 410 and the amplification program 344a that amplify the intensity of reflected light received by the light receiving sensor 400 with the gain determined by the light receiving sensor 400, and the intensity of the reflected light amplified by the amplification unit 410 and the amplification program 344a is a predetermined threshold value. Is determined as the external obstacle 10, the timing determined as the external obstacle 10 by the determination program 344 d, the horizontal synchronization signal of the image signal, and the pixel clock signal, And a calculation program 344e for calculating position information of the obstacle 10.
According to the present invention, the execution of the gain adjustment program 344b of the CPU 341 specifies the reflection position of the reflected light received by the light receiving sensor 400, is reflected at the specified reflection position, and is received by the light receiving sensor 400. Since the gain of the intensity of the reflected light is determined, it is possible to adjust the gain in consideration of the influence of the attenuation factor of the light intensity of the reflected light according to the reflection position. The variation in the identification accuracy of the external obstacle 10 due to can be suppressed. Further, by executing the calculation program 344e of the CPU 341, the position information of the external obstacle 10 is easily calculated based on the timing determined as the external obstacle 10 by the execution of the determination program 344d, and the horizontal synchronization signal and the pixel clock signal. As a result, a special configuration for detecting the position of the external obstacle 10 is not required. Further, the calculation of the position information is not performed based on the amount of reflected light received by the light receiving sensor 400, and thus does not require complicated calculations.
Therefore, the present invention can be said to be a projector that can easily detect the position of an external obstacle and has high identification accuracy of the external obstacle.

Further, when the CPU 341 executes the gain adjustment program 344b, the gain is determined based on the distance between the reflection position and the light receiving sensor 400.
That is, by extracting the analog / digital gain corresponding to each reflection position from the gain data 344c that determines the analog / digital gain based on the distance between the reflection position and the light receiving sensor 400, the light reception at each reflection position is performed. Sensitivity can be made uniform.

Further, the gain adjustment program 344b may determine which area the specified reflection position belongs to among a plurality of areas that have been divided in advance, and determine the gain for each area.
That is, in the gain data 344c, the projection plane 123 is divided into areas so that the light receiving sensitivity at each reflection position is equal to or higher than a predetermined value, and the analog / digital gain is set to a value suitable for each area. Thus, since it is not necessary to change the gain for each reflection position, an increase in the processing load on the CPU 341 can be suppressed, and the light receiving sensitivity at each reflection position can be ensured.

In addition, the projector 100 amplifies the analog light intensity signal of the intensity of the reflected light received by the light receiving sensor 400 with the amplifying unit 410, and the CPU 341 converts the analog light intensity signal into an A / D converted digital light intensity signal. Is amplified by executing the amplification program 344a.
That is, fine amplification adjustment can be performed by amplifying the intensity of the reflected light received by the light receiving sensor 400 to a predetermined value or more by the amplifier 410 and executing the amplification program 344a of the CPU 341.

Further, the projector 100 can update the gain determined by the execution of the gain adjustment program 344b every predetermined period by executing the update program 344f of the CPU 341.
That is, the gain of the gain data 344c is not set to a fixed value, and the peak value of the intensity of the reflected light amplified by the gain before the change is reflected to determine a new gain for each predetermined period. The sensitivity can be improved to a more suitable one.

The scope of the present invention is not limited to the above embodiment, and various improvements and design changes may be made without departing from the spirit of the present invention.
For example, in the above embodiment, the intensity of the reflected light detected by the light receiving sensor 400 through both the amplification of the analog light intensity signal by the amplification unit 410 and the amplification of the digital light intensity signal by execution of the amplification program 344a. However, it may be configured to amplify only one of the analog light intensity signal and the digital light intensity signal.
In addition, the digital light intensity signal of the intensity of the reflected light detected by the light receiving sensor 400 is amplified by the execution of the amplification program 344a. Of course, a digital amplifier or the like may be provided between 420 and the CPU 341.
Furthermore, although the galvanometer mirror is illustrated as the scanner mirror 372 in the above embodiment, a two-dimensional MEMS (Micro E) that can control laser light independently in two axial directions.
A Electro Mechanical System (mirror) may be used.

100 projectors 361 and 362 LD (laser light source)
372 Scanner mirror (scanning unit)
383 Beam splitter 400 Light receiving sensor 410 Amplifying unit (amplifying means, analog amplifying means)
341 CPU (determination means, amplification means, digital amplification means, determination means, calculation means, update means)
344 Storage unit 344a Amplification program (amplification means, digital amplification means)
344b Gain adjustment program (determination means)
344d determination program (determination means)
344e Calculation program (calculation means)
344f update program (update means)

Claims (8)

A light source that outputs laser light, scanning means that scans the laser light, a beam splitter that divides the laser light scanned by the scanning means into a first direction and a second direction, and projection in the first direction a light receiving sensor for receiving the laser beam reflected by an external obstacle located in the laser beam of the area to be irradiated to the surface, the scanning position by the scanning means, based on the light reception of the light receiving sensor, the external fault Calculating means for calculating the position of the object,
The laser beam in the first direction is irradiated with a first laser beam that has passed through the beam splitter and a second laser beam that does not pass through the beam splitter.   The projector according to claim 1, wherein the scanning by the scanning unit is based on a horizontal synchronization signal and a pixel clock signal.   The projector according to claim 1, wherein the second laser light is irradiated so that at least a part of the first laser light is adjacent to the first laser light. The projector according to any one of claims 1 to 3, wherein the first laser light is applied to the projection surface in the first direction so as to form a square shape. 5. The projector according to claim 4, wherein the second laser light is irradiated such that at least a part of one side of the quadrilateral farthest from the light receiving sensor is adjacent. Amplifying means for amplifying the amount of light received by the light receiving sensor;
Determining means for determining an amplification amount based on the calculated position;
The projector according to any one of claims 1 to 5 , further comprising: The determining means includes
The projector according to claim 6 , wherein an amplification amount in the amplification unit is determined based on a distance between the calculated position and the light receiving sensor. The projector according to claim 7 , wherein the amplification amount is increased as a distance between the calculated position and the light receiving sensor is increased.

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