IMAGE DISPLAY SYSTEM AND IMAGE DISPLAY METHOD

Abstract

This image display system comprises: a plurality of semiconductor light sources that respectively output a plurality of optical signals respectively including a plurality of modulated signal portions of mutually different timings; a plurality of optical fiber cables that respectively transmit the plurality of optical signals; a light combining unit that combines the plurality of optical signals from the plurality of optical fiber cables so as to output a combined optical signal; a light quantity detection unit that detects an output light quantity of the combined optical signal; a modulated signal detection unit that detects the plurality of modulated signal portions from the output light quantity of the combined optical signal; a video modulation unit that modulates the combined optical signal according to a video signal, and outputs modulated video light; and a light source control unit that outputs, respectively to the plurality of semiconductor light sources, a plurality of drive control signals which respectively cause the plurality of semiconductor light sources to output the plurality of optical signals respectively including the plurality of modulated signal portions according to the video signal, and that detects, on the basis of the presence / absence of a modulated signal portion among the plurality of modulated signal portions, a fault in the plurality of optical fiber cables.

Description

[Technical field]

[0001] The present disclosure relates to an image display system and an image display method in which a light source unit and an optical modulation unit are configured to be separated and connected via an optical transmission unit including a plurality of optical fiber cables, and which displays an image of a video signal. [Background technology]

[0002] Patent Document 1 discloses a light source device used in a projector, for example, that can detect damage to an optical fiber cable without changing the color even during image projection. The light source device according to the conventional technology includes multiple light sources, a group of optical fiber cables, a drive unit that drives the multiple light sources, a sensor that receives a portion of the light emitted from the group of optical fiber cables and detects the amount of the light, and a determination unit that obtains a signal according to the amount of light detected by the sensor.

[0003] Here, the driving unit supplies driving current to the plurality of light sources, and superimposes a first pulse current and a second pulse current of opposite polarity on the driving current at a predetermined timing for a light source among the plurality of light sources that emits light of a color to be inspected. Also, the determining unit determines the presence or absence of an abnormality in the optical fiber cable that propagates the light of the color to be inspected, based on the difference between the amount of light of the color to be inspected detected by the sensor under the current amount of the driving current and the amount of light of the color to be inspected detected under the current amount on which the first pulse current or the second pulse current is superimposed. This makes it possible to obtain a light source device that can detect damage to an optical fiber cable without changing the color even during image projection. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-191926 A Summary of the Invention

[0005] However, since the optical output of the light source on which the first pulse current is superimposed increases at the timing of superimposing the first pulse current, it is necessary to set the optical output at the timing of superimposing the first pulse current smaller than the maximum optical output that the light source can output, and it is necessary to set the optical output at the timing of not superimposing the first pulse current even smaller than the maximum optical output that the light source can output. Therefore, there was a problem that the introduction of a mechanism for detecting damage to this optical fiber cable would reduce the optical output of the light source device.

[0006] The present disclosure provides an image display system and an image display method equipped with an optical fiber cable fault detection function that can detect faults in an optical fiber cable without reducing the optical output and without causing visible interference to the displayed image even during image projection.

[0007] Here, a fault or failure in an optical fiber cable refers to a fault state in which an optical fiber cable is damaged or broken, making it impossible to transmit an optical signal.

[0008] The image display system according to the present disclosure comprises: a plurality of semiconductor light sources each outputting a plurality of optical signals each including a plurality of modulated signal portions having different timings by driving a semiconductor light source element; a plurality of optical fiber cables respectively connected to the plurality of semiconductor light sources and respectively transmitting the plurality of optical signals; an optical combiner that combines the plurality of optical signals output from the plurality of optical fiber cables, respectively, and outputs the combined optical signal; a light amount detection unit that detects an output light amount of the combined optical signal from the optical combiner; a modulated signal detection unit that detects the plurality of modulated signal portions from the detected output light amount of the combined optical signal; an image modulation unit that modulates the combined optical signal from the optical combining unit in accordance with an input image signal and outputs modulated image light; a light source control unit that outputs a plurality of drive control signals to the plurality of semiconductor light sources in accordance with the video signal, the drive control signals causing the plurality of semiconductor light sources to output the plurality of optical signals each including the plurality of modulated signal portions, and detects a fault in the plurality of optical fiber cables based on the presence or absence of a modulated signal portion among the detected plurality of modulated signal portions; Equipped with.

[0009] According to the image display system etc. of the present disclosure, a fault in an optical fiber cable can be detected without reducing the optical output and without causing visible interference to the displayed image even during image projection. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of an image display system according to an embodiment. [Diagram 2] 2 is a timing chart of signal waveforms showing an example of the operation of the image display system of FIG. 1; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the same or similar components are denoted by the same reference numerals.

[0012] Hereinafter, the embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanation of already well-known matters or duplicate explanation of substantially the same configuration may be omitted. This is to avoid the following explanation becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

[0013] The inventor provides the accompanying drawings and the following description so that those skilled in the art can fully understand the present disclosure, and does not intend for them to limit the subject matter described in the claims.

[0014] (Embodiment 1) Hereinafter, the first embodiment will be described with reference to FIGS.

[0015] [1-1. Configuration] FIG. 1 is a block diagram showing an example of the operation of an image display system having a function of detecting a fault in an optical fiber cable according to an embodiment.

[0016] In FIG. 1, the image display system includes a light source unit 1, an optical transmission unit 2, and an optical modulation unit 3. Here, the light source unit 1 and the optical modulation unit 3 are separated by a predetermined distance and connected via the optical transmission unit 2. The light source unit 1 includes a plurality of N semiconductor light sources 11-1 to 11-N (hereinafter collectively referred to as "11"), a light source control unit 10 that drives and controls the semiconductor light sources 11, and a display unit 12. The optical transmission unit 2 includes a plurality of N optical fiber cables 20-1 to 20-N (hereinafter collectively referred to as "20"). Furthermore, the optical modulation unit 3 is a projection type image display device such as a projector, and includes a light combining unit 31, a light amount detection unit 32, a modulation signal detection unit 33, an image modulation unit 34, and a projection lens 35.

[0017] The multiple semiconductor light sources 11 drive and control the multiple semiconductor light source elements using multiple drive control signals Sd1 to SdN (each including a modulation signal portion generated sequentially at different timings) from the light source control unit 10 to generate multiple optical signals S1 to SN, which are output to the corresponding optical fiber cables 20-1 to 20-N. The multiple optical fiber cables 20 are connected to the multiple semiconductor light sources 11, respectively, and transmit the optical signals S1 to SN, outputting them to the optical combiner 31 of the optical modulation unit 3.

[0018] The optical combiner 31 combines a plurality of optical signals S1'-SN' output from a plurality of optical fiber cables 20, and outputs the combined optical signal Sc to the light amount detector 32 and the video modulator 34. The light amount detector 32 detects the output light amount of the combined optical signal Sc from the optical combiner 31, and outputs a light amount detection signal Sd to the modulation signal detector 33. The modulation signal detector 33 detects a modulation detection signal Sm including a plurality of modulation signal portions from the output of the light amount detector 32, for example using a high-pass filter, and outputs the modulation detection signal Sm to the light source controller 10.

[0019] The image modulation unit 34 is, for example, a DMD (Digital Micro-mirror Device), and outputs a modulation timing signal St indicating a time period T1 including timings for generating modulated signal portions at different timings (timings t1 to t4 in FIG. 2) in the optical signals S1 to SN of the semiconductor light source 11 based on the inputted image signal to the light source control unit 10, and also intensity-modulates the combined optical signal Sc from the optical combining unit 31 according to the inputted image signal to generate image light, which is projected onto the screen 4 via the projection lens 35.

[0020] The light source control unit 10 sequentially generates modulated signal portions at mutually different timings (timings t1 to t4 in FIG. 2) within the on-period (time period T1 in FIG. 2) of the modulation timing signal St, and outputs them as drive control signals Sd1 to SdN to the semiconductor light sources 11-1 to 11-N. The light source control unit 10 also detects which of the multiple optical fiber cables 20 has a fault, based on the presence or absence of each of the multiple modulated signal portions included in the modulation detection signal Sm. In other words, if there is a fault in the optical fiber cable 20, the optical signals S1' to SN' output from the optical fiber cable 20 do not contain a modulated signal portion, and therefore no modulation occurs in the corresponding portion of the modulation detection signal Sm. Therefore, the light source control unit 10 determines that there is a fault in the optical fiber cable 20 corresponding to the modulated signal portion not detected by the modulated signal detection unit 33 among the multiple modulated signal portions included in the modulation detection signal Sm, displays the determination result on the display unit 12, and when it has determined so, stops driving the semiconductor light source 11 connected to the optical fiber cable 20 determined to have a fault.

[0021] [1-2. Operation] Fig. 2 is a timing chart of signal waveforms showing an example of the operation of the image display system of Fig. 1. The operation of the image display system according to the embodiment configured as above will be described below.

[0022] 2 illustrates a case where N=4, the present disclosure is not limited to this, and N may be a multiple number other than 4. In other words, N is set to a required number depending on the number of optical fiber cables for optical output that are required.

[0023] 2, when the semiconductor light source element of the semiconductor light source 11 controls the light source light on / off by switching using, for example, a plurality of subfields, the image modulation section 34 of the optical modulation section 3 outputs this modulation timing signal St in the time period T1 of the subfield used when outputting a relatively large optical signal, and controls the timing (time period) of modulating the semiconductor light source 11, thereby modulating the semiconductor light source 11 in the time period T1 of the subfield used to output a relatively large optical signal. Note that in the time period T2 other than the time period T1, the modulated signal portion is not transmitted. This makes it possible to always reduce the ratio of the modulated signal portion component in the output of the optical signal, making the modulated component less visible.

[0024] The light source control unit 10 generates modulated signal portions by sequentially switching the optical signals S1 to S4 of the semiconductor light sources 11-1 to 11-4 in time and performing on / off modulation at a constant cycle without changing the maximum output value of the optical signals S1 to S4 as shown in Fig. 2 based on the modulation timing signal St. Specifically, as shown in Fig. 2, the optical signals S1 to S4 of the semiconductor light sources 11-1 to 11-4 have modulated signal portions starting from timings t1 to t4, respectively.

[0025] The optical signals S1' to SN' output from the multiple optical fiber cables 20 are combined by the optical combiner 31, and the light amount of the combined optical signal Sc is detected by the light amount detector 32. As shown in FIG. 2, the light amount detection signal Sd of the light amount detector 32 has four modulated signal parts starting from timings t1 to t4 in the case of four semiconductor light sources 11-1 to 11-4, since the optical signal output of the semiconductor light source 11 that is not modulated is combined with the optical signal output of the semiconductor light source 11 that is modulated, as shown in FIG. 2. Also, as shown in FIG. 2, the light amount detection signal Sd is a modulated optical signal waveform in which the component of the modulated signal part is superimposed on a relatively large DC component, since the output of the optical signal of the three semiconductor light sources 11 that are not modulated is combined with the output of the optical signal of one semiconductor light source 11 that is modulated. When the number of semiconductor light sources 11 is N, the ratio of the component of the modulated signal part to the DC component, that is, the component of the modulated signal part / DC component, is about 1 / N, and when N becomes large, it becomes difficult to stably detect the component of the modulated signal part. The modulated signal detector 33 can remove the DC component by performing high-pass filtering, for example, to obtain the modulated detection signal Sm as shown in FIG. 2, and can accurately detect the component amount of the modulated signal portion.

[0026] Since the light source control unit 10 knows which of the multiple semiconductor light sources 11 is being modulated, by monitoring the modulation detection signal Sm from the modulation signal detection unit 33, it is possible to determine which of the multiple optical fiber cables 20 is experiencing a fault.

[0027] Furthermore, the image modulation unit 34 intensity-modulates the combined optical signal Sc from the optical combining unit 31 in accordance with the input image signal, and projects the image light onto the screen 4 via the projection lens 35, thereby obtaining an image of the image light on the screen 4.

[0028] [1-3. Effects, etc.] According to the embodiment configured as above, since the semiconductor light sources 11 perform on / off modulation, the instantaneous maximum output value of the optical signals S1 to SN of each semiconductor light source 11 can be set to the maximum output value of the semiconductor light source 11 used. Also, the time period for outputting the optical signals S1 to SN can be easily shortened within a detectable range. For example, when the video modulation unit 34 operates at 60 Hz, the period can be shortened to 166 μsec, which is 1 / 100 of the period of 16.6 msec. By taking such consideration, the decrease in optical output due to the use of an optical signal having a modulated signal portion for failure detection can be made very small, less than 1%. When the number of semiconductor light sources 11 used is relatively large, it is possible to modulate the optical signal from one semiconductor light source 11 in 16.6 msec, for example, and the loss due to failure of the optical fiber cable can be minimized.

[0029] Furthermore, by adjusting the timing (time period) of modulation in accordance with the modulation timing signal St from the video modulation unit 34, the effect of the modulation on the video optical output is controlled so that it is not visible when viewing the output video, making it possible to monitor for damage, breakage, and other faults in the multiple optical fiber cables 20 while displaying the video.

[0030] (Other embodiments) As described above, the first embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made as appropriate.

[0031] Therefore, other embodiments will be exemplified below.

[0032] In the first embodiment configured as above, a method of removing the DC component using a high-pass filter has been described as an example of the detection means of the modulated signal detection unit 33, but the present disclosure is not limited to this, and the detection means of the modulated signal detection unit 33 may be any means that separates the modulated signal portion from the DC component. Therefore, the detection means of the modulated signal detection unit 33 is not limited to the above-mentioned high-pass filter processing. If a band-pass filter with the modulation repetition frequency as the center frequency is used, it is possible to prevent erroneous detection due to high-frequency noise in addition to removing the DC component.

[0033] As described above, the embodiments have been described as examples of the technology in the present disclosure. For this purpose, the accompanying drawings and detailed description have been provided.

[0034] Therefore, among the components described in the attached drawings and the detailed description, not only are there components essential for solving the problem, but there may also be components that are not essential for solving the problem in order to illustrate the above technology. Therefore, the fact that such non-essential components are described in the attached drawings or the detailed description should not be interpreted as immediately indicating that such non-essential components are essential.

[0035] Furthermore, since the above-described embodiments are intended to illustrate the technology in the present disclosure, various modifications, substitutions, additions, omissions, and the like can be made within the scope of the claims or their equivalents. [Industrial Applicability]

[0036] The present disclosure is applicable to an image display system and an image display method in which a light source unit and an optical modulation unit are configured to be connected separately via an optical transmission unit including a plurality of optical fiber cables, and an image of a video signal is displayed. Specifically, the present disclosure is applicable to, for example, a two-body type projector. [Explanation of symbols]

[0037] 1 Light source section 2 Optical transmission section 3 Optical modulation section 4 Screens 10 Light source control unit 11,11-1~11-N Semiconductor light source 12 Display section 20,20-1~20-N Optical fiber cable 31 Photosynthetic Division 32 Light quantity detection section 33 Modulation signal detector 34 Video Modulation Section 35 Projection Lens S1~SN,S1'~SN' Optical signal Sc combined optical signal Sd Light quantity detection signal Sd1~SdN Drive control signals Sm Modulation detection signal St Modulated Timing Signal t1~t4 Timing T1,T2 time period

Claims

1. a plurality of semiconductor light sources each outputting a plurality of optical signals each including a plurality of modulated signal portions having different timings by driving a semiconductor light source element; a plurality of optical fiber cables respectively connected to the plurality of semiconductor light sources and respectively transmitting the plurality of optical signals; an optical combiner that combines the plurality of optical signals output from the plurality of optical fiber cables, respectively, and outputs the combined optical signal; a light amount detection unit that detects an output light amount of the combined optical signal from the light combining unit; a modulated signal detection unit that detects the plurality of modulated signal portions from the detected output light amount of the combined optical signal; an image modulation unit that modulates the combined optical signal from the optical combining unit in accordance with an input image signal and outputs modulated image light; a light source control unit that outputs a plurality of drive control signals to the plurality of semiconductor light sources in accordance with the video signal, the drive control signals causing the plurality of semiconductor light sources to output the plurality of optical signals each including the plurality of modulated signal portions, and detects a fault in the plurality of optical fiber cables based on the presence or absence of a modulated signal portion among the detected plurality of modulated signal portions; An image display system comprising:

2. the light source control unit determines that an optical fiber cable corresponding to a modulated signal portion not detected by the modulated signal detection unit among the plurality of modulated signal portions is faulty; 2. The image display system according to claim 1.

3. when it is determined that the optical fiber cable corresponding to the modulated signal portion not detected by the modulated signal detection unit is faulty, the light source control unit stops driving a semiconductor light source connected to the optical fiber cable determined to be faulty.

3. The image display system according to claim 2.

4. a projection lens that projects the image light from the image modulation unit onto a screen; The image display system according to any one of claims 1 to 3, further comprising:

5. a plurality of semiconductor light sources each outputting a plurality of optical signals each including a plurality of modulated signal portions having different timings by driving a semiconductor light source element; a plurality of optical fiber cables respectively connected to the plurality of semiconductor light sources and respectively transmitting the plurality of optical signals; an optical combiner that combines the plurality of optical signals output from the plurality of optical fiber cables, respectively, and outputs the combined optical signal; a light amount detection unit that detects an output light amount of the combined optical signal from the light combining unit; a modulated signal detection unit that detects the plurality of modulated signal portions from the detected output light amount of the combined optical signal; and an image modulation unit that modulates the combined light signal from the light combining unit in accordance with an input image signal, and outputs modulated image light, outputting, to the plurality of semiconductor light sources, a plurality of drive control signals for causing the plurality of semiconductor light sources to output, respectively, the plurality of optical signals each including the plurality of modulation signal portions in accordance with the video signal; detecting a fault in the plurality of optical fiber cables based on the presence or absence of a modulated signal portion among the detected plurality of modulated signal portions; A, including image display methods.

6. The step of detecting a fault includes a step of determining that an optical fiber cable corresponding to a modulated signal portion not detected by the modulated signal detection unit among the plurality of modulated signal portions has a fault, The image display method according to claim 5 .

7. The step of detecting a fault includes a step of stopping driving of a semiconductor light source connected to the optical fiber cable determined to have a fault when it is determined that the optical fiber cable corresponding to the modulated signal portion not detected by the modulated signal detection unit has a fault, The image display method according to claim 6 .

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