METHOD FOR DETECTING EMITTED LIGHT FROM DISPLAY SCREEN AND DISPLAY APPARATUS

A method for detecting emitted light from a display screen with a simple configuration and procedure without changing the position of the sensor. A method for detecting emitted light from a display screen of a display apparatus, including: a placement step of placing a photometric part including an optical sensor and a light guide member on a front surface side of the display screen, and a detection step of turning on any area of the display screen, guiding the emitted light from the area to the optical sensor by the light guide member, and detecting the emitted light with the optical sensor without changing the position of the optical sensor.

FIELD

This invention relates to the detection of emitted light from a display screen.

BACKGROUND

Various methods have been developed to detect emitted light from some areas of the display screen in display apparatuses. For example, Patent Literature 1 discloses measuring the emitted light from each pixel in a display apparatus in which the light source of the backlight is controlled to blink, while moving the line sensor in accordance with the timing of pixel lighting.

Patent Literature

Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2017-161754 Summary

However, the configuration described in Patent Literature 1 uses a movable sensor, which requires control of the sensor’s movement, making the circuit configuration complex and requiring operation for the movement.

The present invention was made in view of these circumstances, and an object of the invention is to provide a method for detecting emitted light from a display screen with a simple configuration and procedure without changing the position of the sensor.

The present invention provides a method for detecting emitted light from a display screen of a display apparatus, comprising: a placement step of placing a photometric part including an optical sensor and a light guide member on a front surface side of the display screen, and a detection step of turning on any area of the display screen, guiding the emitted light from the area to the optical sensor by the light guide member, and detecting the emitted light with the optical sensor without changing the position of the optical sensor.

With this configuration, the emitted light from any area of the display screen is guided by the light guide member provided on the front side of the display screen to the optical sensor and is detected. This allows detection of the emitted light from the display screen with a simple configuration and procedure, without using a movable sensor and without changing the position of the optical sensor.

The following are examples of various embodiments of the invention. The embodiments shown below can be combined with each other. Also, each feature independently constitutes an invention.

Preferably, the method comprising a luminance identification step for identifying a luminance corresponding to the emitted light detected in the detection step.

Preferably, the method further comprising a chromaticity identifying step to identify a chromaticity corresponding to the emitted light detected in the detecting step.

Preferably, at least one of a front surface and/or a back surface of the light guide member has a diffuse reflection structure.

Preferably, a reflection structure is formed on the front surface of the light guide member.

Preferably, the photometric part is detachable from the display apparatus.

Preferably, the method further comprising a step of causing a display device disposed on the display screen to emit light.

According to another aspect, a display apparatus capable of detecting emitted light from a display screen comprising a control unit, wherein, a photometric part including a light guide member and an optical sensor is provided on a front surface side of the display screen, the control unit is configured to turn on any area of the display screen without changing the position of the optical sensor, and the emitted light from the area is guided by the light guide member to the optical sensor and is detectable by the optical sensor.

DETAILED DESCRIPTION

1. First Embodiment

1.1. Configuration of Display Apparatus 10

Referring toFIGS.1and2, the configuration of the display apparatus10is described.

As shown inFIG.1A, the display apparatus10is composed of a display part1, a bezel2, and a leg part3. The display part1displays images (including still and moving images) on a display screen4. The bezel2is attached from the back to the side of the display part1and is made of an insulating material, such as engineering plastic. Although not shown in detail, the bezel2is provided with a power indicator, various keypads for user operation, and a speaker. The leg part3is attached to the back of the bezel2and supports the display part1.

As shown inFIG.1B, an optical sensor5is located inside the bezel2at the front of the display part1. In the display apparatus10of this embodiment, four optical sensors5are located at the top, bottom, left, and right positions inside the bezel2so as to surround the outer circumference of the display screen4.

As shown inFIG.2, the display screen4has a display device6and a protective glass7located on the rear side of the display part1. The display device6is composed of an organic EL display panel, for example, and displays images when light emitting elements corresponding to the pixels of the display screen4emit light. The protective glass7is placed on a front surface side of the display screen4to protect the display device6. As will be described in detail later, the protective glass7passes the emitted light from the display device6and also functions as a light guide member that reflects the emitted light and guides it to the optical sensors5. In the example shown inFIG.2, the optical sensors5are located on the side of the protective glass7, but they are not limited to this example and may be located on the side of the display device6, for example. In order to guide all the emitted light from the display device6to the optical sensors5without leaking outward, all the side surfaces of the protective glass7or display device6where the optical sensors5are located may be mirror-finished, except for the location of the optical sensors5.

1.2. Functional Configuration of Display Apparatus 10

Referring toFIG.3, the functional configuration of the display apparatus10will be described. As shown inFIG.3, the display apparatus10has, in addition to the optical sensors5and display device6described above, a control unit8and a memory unit15. The control unit8includes a display control section11, a sensor control section12, a luminance identification section13, and an unevenness correction processing section14.

The display control section11controls the emitted light from the display device6. The sensor control section12identifies the intensity of the emitted light detected by the optical sensors5. The luminance identification section13identifies the luminance of the emitted light detected by the optical sensors5. The unevenness correction processing section14corrects the unevenness of the luminance of the display screen4. Details of each function are described later.

Each of the above components may be realized by software or by hardware. In the case of software realization, various functions can be realized by the CPU (Central Processing Unit) executing a program. The program may be stored in the memory unit15, which may be realized by memory, HDD (Hard Disk Drive), or SSD (Solid State Drive), or may be stored on a computer-readable, non-transitory recording medium.

Each of the above components may also be realized by so-called cloud computing by reading a program stored in an external memory. Also, for hardware realization, various circuits such as an ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array), or DRP (Dynamic Reconfigurable Processor).

1.3. Updating Process of Correction Data for Luminance Unevenness

Referring toFIGS.4to6, the updating process of correction data for luminance unevenness on the display apparatus10is explained. As shown inFIG.4, first, in step S110, the display control section11turns on partial areas of the display screen4and emits the emitted light. Specifically, as shown inFIG.5A, the display control section11causes a part of the display device6to emit light, sequentially from R1, the upper left area of the display screen4, to Rn, the lower right area of the display screen4.

Here, the shape, size, and number of sequentially turned-on areas may be set as desired, but it is preferable to set them so that they cover the entire display screen4. The areas may be set to be mutually exclusive, or they may be set to overlap each other.

In step S120, the emitted light from the turned-on area is detected by the optical sensors5. As shown inFIG.5B, the emitted light from the partial areas of the display screen4is reflected in the protective glass7, which functions as a light guide member, and is detected by the optical sensors5.

In step S130, the sensor control section12determines whether or not emitted light from all areas of the display screen has been detected. If emitted light from all areas is detected (Yes in step S130), step S140is performed. If emitted light from all areas is not detected (No in step S130), steps S110and S120are repeated.

In step S140, the luminance identification section13identifies the luminance of each turned-on area based on the detection results of the optical sensors5(i.e., the detected emitted light intensity). As shown inFIG.6, the sensor calibration coefficient matrix C is stored in the memory unit15. The sensor calibration coefficient matrix C has a correspondence between the luminance value for each area of the display screen4measured with a luminance meter or the like at the time of manufacture of the display apparatus10and the detection value of the optical sensors5detection values when the area is turned on. The luminance identification section13identifies the luminance of each turned-on area of the display screen4based on the detection result data R of the optical sensors5and the sensor calibration coefficient matrix C.

In step S150, the unevenness correction processing section14updates the unevenness correction data M. As shown inFIG.6, the memory unit15has the unevenness correction data M and an unevenness correction target matrix T. The unevenness correction data M is a data related to the amount of correction for the luminance unevenness of each area of the display screen4measured at the time of manufacture of the display apparatus10, and is referred to when performing luminance unevenness correction for any image data. The unevenness correction target matrix T is a data that defines the amount of luminance unevenness (the rate of change of luminance relative to the reference value) that should be targeted for each area of the display screen4. The updated unevenness correction data Mref can be represented by the following equation (1). The updated unevenness correction data Mref is used for subsequent correction of luminance unevenness. [Equation 1]

As described above, the display apparatus10in this embodiment is provided with the protective glass7as a light guide member, the optical sensors5, and the control unit8. The protective glass7is installed on the front surface side of the display screen4, and the optical sensors5are installed on the outer periphery of the display screen4. The control unit8turns on partial areas of the display screen4. The emitted light from the area is guided to the optical sensors5by the protective glass7as a light guide member, and is detected by the optical sensors5.

This configuration allows detection of emitted light from the display screen with a simple configuration and procedure. Also, based on the detection result of the emitted light, the correction data for luminance unevenness of the display screen4can be updated, enabling appropriate correction processing for luminance unevenness.

Referring toFIG.7, a variation1of the first embodiment will be described. As shown inFIG.7, on the front surface of the protective glass7in variation1, a pattern7ais formed to reflect the emitted light from the display device6. The pattern7amay be formed by dot printing on the front surface of the protective glass7or may be realized by attaching a lens structure to the front surface of the protective glass7. This configuration allows for the specific realization of a light guiding member that guides the emitted light from the display device6to the optical sensors5.

Referring toFIGS.8A and8B, variation2will be described. As shown inFIGS.8A and8B, on the front surface of the protective glass7in variation2, the light guide plate7bis attached to change the passage and reflection of the emitted light as an electric field is applied. The light guide plate7bis realized, for example, in PDLC (Polymer Dispersed Liquid Crystal) glass.

In this case, as shown inFIG.8A, by applying an electric field to the light guide plate7b, the emitted light from the display device6is passed through the protective glass7and the light guide plate7b. In contrast, as shown inFIG.8B, when the application of an electric field to light guide plate7bis stopped, the emitted light from the display device6is reflected by light guide plate7band guided to the optical sensor5.

With this configuration, during normal use, the electric field can be applied to the light guide plate7bto make the display screen4visible. Also, during specific operations such as detecting the emitted light from the display device, the application of an electric field to the light guide plate7bcan be stopped and the emitted light from the display device6can be guided to the optical sensor5. This allows separate control for the use of the device.

Referring toFIGS.9A and9B, variation3will be described. As shown inFIG.9A, in variation3, by applying an electric field only to a part of the light guide plate7B, the area in which the emitted light is reflected is configured to be changeable. This configuration allows the area that reflects the emitted light to be changed in accordance with the area to be turned on. In the example shown inFIG.9B, an air layer7cis provided between the protective glass7and the display device6. By providing an air layer7cwith a different refractive index, it becomes easier to transmit the emitted light reflected by the light guide plate7bwithin the protective glass7.

Referring toFIG.10AandFIG.10B, variation4will be described. As shown inFIGS.10A and10B, on the front surface of the protective glass7in variation4, a mirror7dis provided to reflect the emitted light from the display device6as the light guide member. The mirror7dis detachable and can be detached during normal use to allow viewing of the display screen.

FIG.10Aillustrates a flat mirror7d. On the other hand,FIG.10Billustrates the installation of a curved mirror7d. These configurations allow to realize a light guide member that guides the emitted light from the display device6to the optical sensors5using general-purpose products such as flat or curved mirrors.

Referring toFIG.11, variation5will be described. As shown inFIG.11, in variation5, line sensors as optical sensors5are installed inside the bezel2above and below the display screen4. In this case, partial areas R1 to Rn of the display screen4that are turned on by the control unit8should span the left and right sides of the display screen4. This configuration allows the control unit8to quickly perform the process of turning on the area of the display part1and detecting the emitted light (step S110to step S130inFIG.4).

2. Second Embodiment

Referring toFIGS.12and13, the second embodiment of the present invention will be described. The second embodiment differs from the first embodiment in that the invention includes a chromaticity identification step to identify a chromaticity corresponding to the emitted light detected by the optical sensors5. The following description will focus on the differences from the first embodiment.

In the second embodiment, as shown inFIGS.12and13, the control unit8emits each of the R (Red), B (Blue), and G (Green) light emitting elements of the display device6for each area and detects the light intensity of each color with the optical sensors5(steps S110to S240inFIG.13).

In step S250, the control unit8compares the previously measured R, G, and B light intensity and the newly acquired R, G, B detection results to identify the chromaticity of R, G, B for each detected area. In step S260, the control unit8processes the update of the color unevenness correction data so that the ratios of R, G, and B are the same. This allows the display color to be adjusted to the target color.

As a variation of the second embodiment, three types of optical sensors5may be arranged for each of the R, G, and B colors. In this case, by placing one of the R, G, or B filters in front of the photosensitive area of the optical sensors5, for example, the sensors can be configured as sensors for each of the R, G, and B colors. In this way, by measuring the luminous intensity in each color using the optical sensors5corresponding to the color, it is possible to accurately measure the chromaticity even when the chromaticity of each R, G, and B has changed over time.

Referring toFIGS.14and15, the third embodiment of the present invention will be described. The third embodiment differs from the first embodiment in that it uses a photometric part20detachably placed on the front surface side of the display screen4to detect the emitted light from the display device6. The following description will focus on the differences from the first embodiment.

As shown inFIGS.14and15, the photometric part20is used in the third embodiment. The photometric part20has a light propagate portion21as a light guiding member and an optical sensors22. The photometric part20is formed in a flat rectangular shape as an example. As shown inFIG.14B, the photometric part20is preferably provided with an area larger than the display screen4when viewed from the front, and more preferably provided with an area larger than the display apparatus10.

The light propagate portion21is composed of glass or the like, and the front surface21aof the light propagate portion21has a mirror treatment. As a result, the light propagate portion21passes the emitted light from the display device6and also functions as a light guide member that reflects the emitted light and guides it to the optical sensors5. As an example, the optical sensors5are provided at a plurality of predetermined locations (three in the example shown inFIG.14) on the top surface of the photometric part20.

The light propagate portion21may further be provided with a structure to control the reflection direction of the emitted light. The surface of the display device6may also be provided with a structure to diffuse the emitted light.

Thus, in the third embodiment, the photometric part20, which is independent from the display apparatus10, is used to detect the emitted light from any area of the display screen4by the light propagate portion21propagating the light to the optical sensor22. In this way, since the photometric part20is configured to be detachable from the display apparatus10, it is possible to apply the technical concept of the present application to existing display apparatuses of various sizes. Also, since the optical sensors22are provided at a predetermined unchanged position in the photometric part20, a mechanism for moving the optical sensors22and a process for controlling the movement of the optical sensors22are not required.

Referring toFIG.16, variation1of the third embodiment will be described. In the photometric part20in Variant1, the front surface21aof the light propagate portion21is surface treated with a diffuse reflection structure. Such surface treatments can promote diffusion of the emitted light within the light propagate portion21, and thus facilitates guiding the emitted light to the optical sensors22. The diffuse reflective structure can use surface treatments such as dot printing and/or (or) imparting a lens array shape. In these cases, the shape, size, and density of the dot printing pattern and lens array can be designed appropriately, taking into account the shape of the light propagate portion21and its position with the optical sensors22.

Referring toFIG.17, variation2of the third embodiment will be described. In the photometric part20in Variant2, the back surface21bof the light propagate portion21is surface treated with a diffuse reflection structure. Specifically, a diffusion sheet may be attached, or dots may be printed or a lens array shape may be given. Such surface treatments can further promote the diffusion of the emitted light within the light propagate portion21, and thus facilitate the design for guiding the light to the optical sensors22.

Referring toFIG.18, variation3of the third embodiment will be described. In variation3, the optical sensor22is located on the front surface of the photometric part20. One optical sensor22may be placed in the center of the front face of the photometric part20as shown inFIG.18, or it may be placed elsewhere on the front face of the photometric part20. In this case, the front surface21aand the back surface21bof the light propagate portion21should be surface treated with diffuse reflection structure. On the other hand, the position in the front surface21aof the light propagate portion21where the optical sensor22is located should be allowed to pass through the emitted light without surface treatment. Thus, by adjusting the diffuse reflection of the outgoing light in the light propagate portion21accordingly, the emitted light can also be detected by the optical sensor22placed in front of the photometric part20without changing its position.

Referring toFIGS.19and20, variation4of the third embodiment will be described. The photometric part20in variation4has a concave-convex Fresnel mirror24formed on the front surface. The Fresnel mirror24has alternating apex24aand groove24b, and as shown inFIG.19B, is formed on a circular arc centered on the optical sensor22when viewed from the front.

In variation4, as shown inFIG.20, the emitted light from any area of the display device6is passed through the light propagate portion21, reflected by the Fresnel mirror24, and guided through the trajectory Lr to the optical sensor22. Here, because the Fresnel mirror24is formed, the emitted light is reflected at the virtual parabolic surface P and can be guided to the optical sensor22. With this configuration, one optical sensor22is placed in the center of the top surface of the photometric part20, and thus facilitate the design for guiding the emitted light from the display device6to the optical sensor22.

4. Other Embodiments

The implementation of the present invention is not limited to the above embodiments. For example, the number, shape, and location of the optical sensors5are not limited to the above. As an example, there may be only one optical sensor5, or it may be located on the bezel instead of inside the bezel.

In the above embodiment, the display screen4was realized by the light emitting elements of the display device6, but it is not limited to this configuration. For example, the technical ideas of the present disclosure can be applied to so-called liquid crystal panels in which light from the backlight is blocked by the liquid crystal part.

In variation4of Embodiment1above, a detachable mirror7dis used as a light guide member, but the light guide member in other forms may also be detachable.

In the third embodiment, the photometric part20may be provided with a control unit8and perform some or all of the functions of the sensor control section12or the luminance identification section13. The photometric part20may also be a non-detachable arrangement, i.e., a fixed arrangement.

Furthermore, this invention can also be realized as a program that causes the control unit8to perform each of the functions described above.

Furthermore, the invention may be realized as a computer-readable, non-transitory recording medium storing the above-mentioned program.

Various embodiments of the present invention have been described, but these are presented as examples and are not intended to limit the scope of the invention. The embodiments may be variously omitted, replaced, or modified to the extent that the gist of the invention is not departed from. Said embodiments and variations thereof are included in the scope and gist of the invention, as well as in the invention described in the claims and its equivalents.

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