JP5531695B2 - Image display device, computer program for image display device, and image display method - Google Patents

Description

  The present invention relates to an image display device for displaying an image of a light emitting device, a computer program therefor, and an image display method for displaying such an image.

  As an example of a light emitting device including an optical element, a display device and a lighting device are provided. In these light emitting devices, it is often required to emit light with uniform brightness in the light emitting surface.

  For example, in a liquid crystal display device which is an example of a display device, light emitted from a backlight is uniformly diffused in a display surface by a diffusion layer, and this is condensed in a normal direction by a prism film, and further, a liquid crystal cell or a retardation film A predetermined phase difference is controlled by a (phase difference control member) to obtain a light emission state. At this time, if the light emitted from the optical elements such as the backlight, the prism film, and the phase difference control member becomes non-uniform in the display surface, visual unevenness occurs and becomes a problem.

  A plurality of these optical elements are periodically arranged in a one-dimensional or two-dimensional manner in the display surface. For this reason, the visual unevenness caused by the optical element is visually recognized by the viewer as the periodic unevenness.

Here, a method for quantitatively evaluating the degree of visual periodic unevenness is known. For example,
Patent Document 1 describes that an enhanced image is obtained by multiplying a power spectrum of a frequency corresponding to a specific wavelength range that can be recognized with the naked eye by a constant called an enhancement function.
Patent Document 2 describes that a spatial frequency function is used as an enhancement function for multiplying a power spectrum obtained from image data of an object.

In Non-Patent Document 1, a general adult contrast sensitivity (Cs) and spatial frequency [mm ⁻¹ ] when a grayscale image whose density changes sinusoidally on a plane is visually observed at a predetermined viewing distance. The relationship has been reported.

JP-A-6-222002 Japanese Patent Laid-Open No. 10-96669

Michael J. Flynn: Visual Requirements for High-Fidelity Display, Advances in Digital Radiography, RSNA Categorical Course in Diagnostic Radiology Physics, 103-107, 2003.

  However, in the above-mentioned patent document and non-patent document, the visibility of simple sinusoidal periodic unevenness is only studied. For this reason, in order to evaluate the visibility of the unevenness of the period generated in the light emitting device, it is necessary to actually make a prototype of the light emitting device and perform a visual inspection.

  The present invention has been made in view of the above problems, and provides a technique for evaluating a visual periodic unevenness expected to occur in a light emitting device without actually making a prototype.

  The image display device of the present invention is an image display device that displays an image indicating a light emission state of a light emitting device including periodically arranged optical elements, and is a plurality of types related to at least one dimension design value of the optical element. A condition acquisition unit that acquires an input value of the optical element, and a model acquisition unit that acquires an image indicating a visual period variation related to a light emission state of the light emitting device when the dimension design value of the optical element is the input value. And a display unit for displaying the plurality of generated images.

  According to the above-mentioned invention, an image showing the visual periodic unevenness related to the light emitting state of the light emitting device when the dimensional design value of the optical element is changed in plural ways is acquired and displayed. For this reason, it is possible to visually evaluate visual periodic unevenness of various conditions generated in the light emitting device.

  The computer program of the present invention is a computer program for an image display device that displays an image showing a light emission state of a light emitting device including optical elements that are periodically arranged, and is at least one of dimensional design values of the optical elements. A condition acquisition process for acquiring a plurality of input values relating to the two, and generating an image showing a visual period variation related to the light emission state of the light emitting device when the dimension design value of the optical element is the input value The image display apparatus is caused to execute model acquisition processing and display processing for displaying the plurality of generated images.

  The image display method of the present invention is an image display method for displaying an image indicating a light emission state of a light-emitting device including periodically arranged optical elements, and a plurality of methods related to at least one dimension design value of the optical elements. A condition acquisition step of acquiring the input value of the optical element, and a model acquisition step of generating an image showing the visual periodic unevenness of the light emitting state of the light emitting device when the dimension design value of the optical element is the input value; Displaying a plurality of the generated images.

  According to the present invention, an image showing a visual period unevenness expected to occur in the light emitting device when the dimensional design value of the optical element is changed in a plurality of ways is displayed. Thereby, it is possible to know the dimensional design value of the optical element that makes the visual evaluation of the periodic unevenness good without actually making a prototype of the light emitting device.

It is a functional block diagram which shows the image display apparatus of 1st embodiment. (A) is a schematic diagram which shows an example of a light-emitting device, (b) is a graph which shows each theoretical value of the luminance distribution at the time of lighting of each optical element, and the luminance distribution at the time of lighting of the whole light-emitting device. . FIG. 3 is a diagram illustrating a simulated image corresponding to FIG. It is a flowchart which shows the image display method concerning 1st embodiment. It is a functional block diagram which shows the image display apparatus of 2nd embodiment. It is a flowchart which shows the image display method concerning 2nd embodiment. 6 is a graph showing a calculation result 2 of Example 1. 6 is a graph showing a calculation result 3 of Example 1. 6 is a graph showing a calculation result 4 of Example 1. It is a figure which shows the simulation image corresponding to FIG. It is a figure which shows the simulation image corresponding to FIG. FIG. 10 is a diagram illustrating a simulated image corresponding to FIG. 9. It is a graph which shows the visibility sensitivity of a person's brightness irregularity. 6 is a graph showing a calculation result 1 of Example 2. 6 is a graph showing a calculation result 2 of Example 2. It is a figure which shows the simulation image corresponding to FIG. It is a figure which shows the simulation image corresponding to FIG. 6 is a graph showing a moire cycle of Example 3.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

Note that the various components of the present invention do not have to be individually independent, that a plurality of components are formed as one member, and one component is formed of a plurality of members. It may be that a certain component is a part of another component, a part of a certain component overlaps a part of another component, and the like.
In addition, the various components of the present invention may be formed so as to realize the function. For example, dedicated hardware that exhibits a predetermined function, data processing in which a predetermined function is given by a computer program It can be realized as an apparatus, a predetermined function realized in the data processing apparatus by a computer program, an arbitrary combination thereof, or the like.

In addition, the image display device of the present invention can read a program and execute a corresponding processing operation so that a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an I / F (Interface). ) Hardware constructed by general-purpose devices such as units, dedicated logic circuits constructed to execute predetermined processing operations, combinations thereof, and the like.
In the present invention, causing the computer apparatus to execute various processing operations corresponding to the program also means causing the computer apparatus to control the operation of various devices.

  In addition, each storage unit storing data means that the image display device has a function of each storage unit using one or a plurality of storage units, and each data is displayed as an image. It is not necessarily required that the device is actually owned.

Moreover, although the image display method of this invention has described several process in order, the order of the description does not limit the order which performs several process.
Furthermore, the image display method of the present invention is not limited to being executed at a timing at which a plurality of steps are individually different. For this reason, another process may occur during execution of a certain process, or a part or all of the execution timing of a certain process and the execution timing of another process may overlap.

<First embodiment>
First, an outline of the image display device 100 of the present embodiment will be described. FIG. 1 is a functional block diagram showing an image display device 100 of the present embodiment.

The image display device 100 of the present embodiment displays an image (simulated image 10) indicating the light emission state of the light emitting device 200 including the optical elements 210 that are periodically arranged.
The image display device 100 includes a condition acquisition unit 20, a model acquisition unit 30, and a display unit 40.
The condition acquisition unit 20 acquires a plurality of input values related to at least one dimension design value of the optical element 210.
The model acquisition unit 30 acquires an image (simulated image 10) indicating the visual periodic unevenness related to the light emission state of the light emitting device 200 when the dimensional design value of the optical element 210 is an input value.
The display unit 40 displays a plurality of acquired images (simulated images 10).

  Next, the image display device 100 of the present embodiment will be described in more detail.

  The light emitting device 200 is a device containing a light emitter, and examples thereof include a lighting device and a display device such as a liquid crystal display device.

  The optical element 210 is an element periodically arranged in the light emitting device 200. In the case of a lighting device, a light emitter such as an LED (Light Emitting Diode) is used. In the case of a display device, various optical elements 210 can be mentioned.

  For example, as the optical element 210, a light emitter of the light emitting device 200 such as a backlight, an optical film that diffuses or collects transmitted light that passes through the optical element 210, or a liquid crystal cell or retardation film that imparts a phase difference to the transmitted light And the like.

Examples of the visual periodic unevenness relating to the light emitting state of the light emitting device 200 include uneven brightness and uneven color. Among these, luminance unevenness includes uneven light emission (joint unevenness) caused by one-dimensional or two-dimensional arrangement intervals of the light emitter, moire fringes due to interference between layers having a periodic structure, and uneven thickness of the retardation control member. For example, the phase difference caused by
Hereinafter, in this embodiment, luminance unevenness of the light emitting device 200 will be described.

  FIG. 2A is a schematic diagram illustrating an example of the light emitting device 200. In this embodiment, it is possible to display and output simulated images 10 representing the light emission states of various light emitting devices 200. Among these, the figure shows a direct-type backlight for a liquid crystal display (LCD) using a cold cathode fluorescent lamp (CCFL) as an optical element 210.

  The optical element 210 used in the present embodiment has a linear shape extending in the front-rear direction of FIG. 2A. In the figure, eight optical elements 210 accommodated in a housing 240 are arranged in parallel to each other at equal intervals. The direction in which the optical elements 210 are arranged (the horizontal direction in the figure) is the width direction of the light emitting device 200.

The light emitting device 200 (backlight) includes a diffusion plate 220 that faces the eight optical elements 210. The diffuser plate 220 is a member that uniformizes the light emitted from each of the optical elements 210 in a plane.
In addition, a reflection plate 230 is installed on the opposite side of the diffusion plate 220 with the optical element 210 interposed therebetween. The reflection plate 230 is a member that specularly reflects light emitted from the optical element 210 toward the diffusion plate 220.

Here, there are many parameters relating to the light emission characteristics of the light emitting device 200. If the characteristics of the optical element 210, the diffusion plate 220, and the reflection plate 230 themselves are not changed for simplicity, the following parameters are listed as typical parameters.
(i) Center-to-center distance L1 between adjacent optical elements 210
(ii) End distance L2 from the center of the optical element 210 at both ends to the housing 240
(iii) Opposite distance L3 between the optical element 210 and the diffusion plate 220
(iv) Number N of optical elements 210
(v) Width X of the housing 240

X = (N−1) × L1 + 2 × L2 Formula (1)
Therefore, by determining any three of X, N, L1, and L2, the other one is determined by the above equation (1).

FIG. 2B shows the luminance distribution when each optical element 210 (CCFL) is turned on and the entire light emitting device 200 (backlight: BKL) when N = 8 and L2 = L1 / 2. It is a graph which shows a theoretical value with each luminance distribution. The vertical axis represents luminance [cd / m ² ]. However, for simplicity, the influence of the reflector 230 is ignored in this embodiment.

The individual luminance distribution of the optical element 210 (hereinafter sometimes referred to as individual luminance distribution) has a single peak distribution shape centered on the optical element 210.
The luminance distribution of the light emitting device 200 (hereinafter sometimes referred to as the overall luminance distribution) is a combination of the individual luminance distributions of the optical elements 210. Periodic luminance unevenness occurs in the overall luminance distribution. In addition, dark color portions DK having a low luminance are formed in slopes at both ends in the width direction of the overall luminance distribution. This is because the end distance L2 is an amount that cannot be ignored.

  The image display device 100 of the present embodiment acquires and displays a simulated image 10 that simulates the overall luminance distribution corresponding to the light emission state of the light emitting device 200 shown in FIG.

FIG. 3 is a diagram showing a simulated image 10 corresponding to FIG. The left-right direction in FIG. 3 corresponds to the width direction of the light emitting device 200.
As shown in FIG. 3, the simulated image 10 of the present embodiment includes a light color portion BR corresponding to eight optical elements 210 and dark color portions DK at both ends in the width direction, and is one-dimensional in the left-right direction. It can be visually recognized that there is uneven shading.

  FIG. 4 is a flowchart showing an image display method (hereinafter sometimes referred to as a first method) by the image display apparatus 100 of the present embodiment. The first method will be described with reference to FIGS.

The first method relates to a method for displaying the simulated image 10 indicating the light emission state of the light emitting device 200 including the optical elements 210 arranged periodically, and includes a condition acquisition step S20, a model acquisition step S30, and a display step S40.
In the condition acquisition step S20, a plurality of input values related to at least one of the dimension design values of the optical element 210 are acquired.
In the model acquisition step S30, the simulated image 10 indicating the visual periodic unevenness related to the light emission state of the light emitting device 200 when the dimension design value of the optical element 210 is used as the input value is acquired.
In the display step S40, the acquired plurality of simulated images 10 are displayed.

More specifically, in the image display apparatus 100 of the present embodiment, the condition acquisition unit 20 acquires a plurality of input values related to at least one of the dimension design values of the optical element 210 (FIG. 4: step S20). .
After receiving a plurality of input values, the image display apparatus 100 may acquire and display the simulated image 10 corresponding to each of the input values, or after acquiring and displaying the simulated image 10 corresponding to one input value, May be accepted.

The input value acquired by the condition acquisition unit 20 may be the dimension design value itself, or may be another parameter directly or indirectly related to the dimension design value.
Here, the condition acquisition unit 20 acquiring the input value related to the dimension design value includes various aspects. The condition acquisition unit 20 may acquire a numerical value manually input by the user as an input value, or may acquire a numerical range. In addition, a user's selection among a plurality of options related to the dimension design value may be acquired as an input value, or output data of other arithmetic processing or data stored in a storage medium may be captured.

  Here, the user is a user of the image display device 100 of the present embodiment, and a subject who evaluates the visibility of the simulated image 10 of the light emitting device 200.

The dimension design value related to the input value is a parameter regarding the position and quantity of the optical element 210 that is a variable that the user desires to perform a parameter study and is a direct or indirect variation factor of the light emission state of the light emitting device 200. is there.
As the design dimension value, in addition to the dimension of the optical element 210 itself, a relative dimension between the light emitting device 200 and the optical element 210, or the quantity of the optical element 210 can be cited. Specifically, the center-to-center distance (representative length) L1, the end portion distance L2, the facing distance L3, the number (quantity) N, and the width dimension X can be exemplified.

  In addition to the dimension design value, the condition acquisition unit 20 may further accept input of parameters related to optical characteristic values exemplified by the brightness, light transmittance (absorbance), reflectance, etc. of the individual optical elements 210.

The condition acquisition unit 20 converts the input value acquired by the condition acquisition unit 20 into a dimension design value as necessary. The conversion table or conversion formula is stored in the condition storage unit 22.
In addition, the condition acquisition unit 20 may acquire an input value by presenting options related to the dimension design value to the user and receiving the selection from the user.

  The model acquisition unit 30 acquires a dimension design value corresponding to the input value from the condition acquisition unit 20. Then, the model acquisition unit 30 simulates an image 10 showing a visual periodic variation in the light emitting state of the light emitting device 200 when the dimension of the predetermined portion of the optical element 210 is the dimension design value (see FIG. 3). ) Is acquired (FIG. 4: Step S30).

Here, the model acquisition unit 30 acquires the simulated image 10 when the model acquisition unit 30 generates the simulated image 10 corresponding to the acquired dimensional design value and a large number of simulations stored in the storage unit 34 in advance. A case where the model acquisition unit 30 extracts the simulated image 10 corresponding to the acquired dimension design value in the image 10.
Hereinafter, in the present embodiment, a case where the model acquisition unit 30 generates the simulated image 10 will be described.

As shown in FIG. 1, the model acquisition unit 30 includes a calculation unit 32 and a storage unit 34.
The storage unit 34 of the model acquisition unit 30 stores the dimension design value of the optical element 210 and the luminance of the light emitting device 200 in association with each other.

In addition, the storage unit 34 has, for a nominal case corresponding to at least one aspect of the light emitting device 200, a dimensional design value, an optical characteristic value, and the like necessary for the model acquisition unit 30 to generate the simulated image 10 representing the entire luminance distribution. Parameters are stored in advance.
Thereby, the user can obtain the simulated image 10 only by inputting the input value regarding the specific dimension design value for which the parameter study is desired to the condition acquisition unit 20.

  Specifically, the storage unit 34 relates to the light emitting device 200 shown in FIG. 2A, the center-to-center distance L 1, the end part distance L 2, the facing distance L 3, the number N and the width dimension X, and the individual luminance of the optical element 210. Stores distribution waveform information.

Then, the calculation unit 32 changes the dimension design value in the nominal case to the dimension design value received from the user, and creates a two-dimensional grayscale image corresponding to the overall luminance distribution of the light emitting device 200.
Specifically, the calculation unit 32 changes the individual luminance distribution in FIG. 2B by changing the position and number of the optical elements 210 according to the parameter changed by the dimension design value acquired from the condition acquisition unit 20. Rearrange in the horizontal axis direction or vertical axis direction. Specifically, when changing the center distance L1 or the end distance L2, the center position of the individual luminance distribution is moved in the horizontal axis direction in the figure. When changing the facing distance L3 between the optical element 210 and the diffusion plate 220, the waveform of the individual luminance distribution is enlarged or reduced, or moved in the vertical axis direction.

Next, the calculation unit 32 generates an overall luminance distribution by synthesizing the rearranged individual luminance distributions with each other.
Further, the calculation unit 32 multiplies the generated overall luminance distribution by a predetermined coefficient to convert it into luminance (pixel value), and converts it into a two-dimensional gray image, thereby converting the simulated image 10 (see FIG. 3). )

The computing unit 32 generates a simulated image 10 for each of a plurality of dimension design values related to the parameter study. The generated simulated image 10 is displayed and output on the display unit 40 through the display control unit 42 (FIG. 4: step S40).
Thereby, the user who has visually observed the simulated image 10 can know what value the dimensional design value is set to be so that the luminance unevenness of the light emitting device 200 is reduced to a predetermined level or less.

  The display unit 40 is a display device that displays the simulated image 10. The display control unit 42 causes the display unit 40 to display a plurality of generated simulated images 10 side by side and display them simultaneously or sequentially one by one. The condition acquisition unit 20, the model acquisition unit 30, and the display control unit 42 are connected to the bus 90.

  The display unit 40 of this embodiment sequentially displays the simulated images 10 one by one. Further, the display unit 40 alternately displays a plurality of images (simulated image 10) showing periodic unevenness and a clear image without periodic unevenness.

  The clear image herein refers to an image that does not include visible periodic unevenness, and is not limited to a single color image such as black as a whole. That is, the clear image may be an image including the housing 240 of the light emitting device 200 (see FIG. 2A).

  By alternately displaying the clear image and the simulated image 10 as in the present embodiment, it is possible to display the next simulated image 10 after refreshing the user's vision once viewing the simulated image 10. . For this reason, the user can evaluate the visibility of the simulated image 10 without being confused by the impression or afterimage of the previous simulated image 10.

Further, the computer program of the present embodiment causes the computer device (image display device 100) to execute an image display process for displaying the simulated image 10 indicating the light emission state of the light emitting device 200 including the optical elements 210 that are periodically arranged. It is a computer program for.
The image display processing executed by the computer device includes a condition acquisition process for acquiring a plurality of input values related to at least one of the dimension design values of the optical element 210, and a case where the dimension design value of the optical element 210 is an input value. The model acquisition process which produces | generates the simulated image 10 which shows the visual period nonuniformity concerning the light emission state of the light-emitting device 200, and the display process which displays the produced | generated several simulated image 10 are included.

  Here, unlike a parameter having a direct correlation with the overall luminance distribution of the light emitting device 200 such as the radiance of each light emitter, the dimension design value of the optical element 210 gives the light emitting state of the light emitting device 200. It is difficult for humans to grasp the degree of influence sensuously. This is because, as will be described in detail in the examples described later, the luminance unevenness of the light emitting device 200 is difficult to predict, for example, it varies significantly only by increasing or decreasing the number N of the optical elements 210 (cold cathode tubes) by one.

  On the other hand, according to the image display device 100 of the present embodiment, a parameter study on the dimension design value specified by the user can be performed by the simulated image 10 that simulates the light emission state of the light emitting device 200. For this reason, it is possible to accurately and visually evaluate the degree of luminance unevenness quickly and inexpensively without making a prototype of an actual machine in which the parameters are variously changed.

Various modifications are allowed for this embodiment.
For example, in the above embodiment, the individual luminance distribution of the optical element 210 is rearranged based on the dimensional design value acquired from the user, and the model acquisition unit 30 obtains the overall luminance distribution of the light emitting device 200. Is not limited to this.

  In the first place, the method of calculating the luminance unevenness period in the overall luminance distribution of the light emitting device 200 differs depending on the generation factor. For example, in the case of the joint unevenness in the boundary region of the light emitter as in the above embodiment, the center-to-center distance and the grating length of the optical element 210 become the periodic unevenness. On the other hand, in the case of moire fringes due to interference between layers having a periodic structure, the moire frequency is determined by the reciprocal of the period of each thin film. Further, in the case of a phase difference shift caused by the thickness unevenness of the phase difference control member, the period of the thickness unevenness substantially coincides with the period of the brightness unevenness of the light emitting device 200.

  Therefore, the image display apparatus 100 may accept in advance the selection of the type of the light emitting device 200 and the optical element 210 and the type of luminance unevenness of the light emitting device 200 from the user by the condition acquisition unit 20.

  Further, the storage unit 34 stores relation information that associates the dimension design value and the optical characteristic value of the optical element 210 with the overall luminance distribution of the light emitting device 200 according to the type of luminance unevenness. The relationship information may be a function, a table format, or a dedicated circuit. Then, in accordance with the type of luminance unevenness received from the user, the calculation unit 32 calculates the overall luminance distribution of the light emitting device 200 using the dimension design value and the optical characteristic value acquired from the condition acquisition unit 20 or the storage unit 34. However, this may be converted into the simulated image 10.

  As described above, in the image display device 100 of the present embodiment, a number of simulated images 10 each indicating the light emission state of the light emitting device 200 when the dimensional design value is changed in various ways are calculated in advance and stored. You may store in the part 34. FIG. Then, the calculation unit 32 of the model acquisition unit 30 may search the storage unit 34 using the input value acquired by the condition acquisition unit 20 as a search key and acquire the corresponding simulated image 10.

<Second embodiment>
FIG. 5 is a functional block diagram of the image display apparatus 110 of the present embodiment.

The image display device 110 according to the present embodiment is at least different from the image display device 100 according to the first embodiment (see FIG. 1) in that it includes an answer input unit 50, an answer storage unit 60, and a determination unit 70.
The answer input unit 50 receives input of the visibility data VD that represents the visibility of the periodic unevenness of the image (simulated image 10) displayed on the display unit 40.
The answer storage unit 60 stores the received visibility data VD.
The determination unit 70 refers to the answer storage unit 60 to determine the degree of uneven visibility.
The answer input unit 50, the answer storage unit 60, and the determination unit 70 are connected to the bus 90.

  FIG. 6 is a flowchart showing an image processing method (hereinafter also referred to as the present method) by the image display apparatus 110 of the present embodiment. This method will be described with reference to FIGS.

The image display apparatus 110 according to the present embodiment has two modes, a first mode and a second mode, and first asks the user to select a mode (FIG. 6: Step S10).
The first mode (FIG. 6: Step S12) is a method for acquiring and displaying a simulated image 10 of luminance unevenness indicating the light emission state of the light emitting device 200 in accordance with the dimension design value designated by the user. FIG. 4 corresponds to steps S20 to S40). In the present embodiment, the description is omitted.
In the second mode (FIG. 6: Step S50), the dimension design value applied to the simulated image 10 in which the luminance unevenness is determined to be the predetermined visibility based on the visibility data VD of the displayed simulated image 10 is displayed. It is a method to output to. The second mode will be described.

Condition acquisition step S51, model acquisition step S52, and display step S53 correspond to steps S20 to S40 in FIG. 4, respectively.
Specifically, the condition acquisition unit 20 acquires an input value indicating the dimension design value specified by the user (FIG. 6: step S51). The model acquisition unit 30 acquires the reference image by generating or referring to the simulated image 10 indicating the light emission state of the light emitting device 200 corresponding to the dimension design value (FIG. 6: step S52). The display control unit 42 receives the acquired plurality of simulated images 10 from the model acquisition unit 30, switches them at a predetermined timing, and causes the display unit 40 to display and output them (FIG. 6: step S53).

  The user views the simulated image 10 displayed on the display unit 40, and inputs a sensory evaluation value regarding the visibility of the periodic unevenness (luminance unevenness) to the answer input unit 50 as the visibility data VD (FIG. 6: FIG. 6). Step S54).

  The visibility data VD is an evaluation result in which the user has evaluated the degree of visibility of luminance unevenness in the simulated image 10 displayed on the display unit 40 in multiple stages. The answer input unit 50 may selectively accept visibility from two choices, or may selectively accept the conspicuous degree of luminance unevenness in three or more stages. Further, the answer input unit 50 may receive a score value indicating the conspicuous degree of luminance unevenness from the user. The score value may be a perfect score, for example.

  The visibility data VD of the present embodiment is set to give a high score when the degree of unevenness in luminance is low. That is, when the luminance unevenness of the simulated image 10 is evaluated in two stages, the visibility data VD = 0 when the user feels that the brightness unevenness is visible, and the visibility data VD = 1 when the user feels that the luminance unevenness is not visible. Shall be given.

  The answer storage unit 60 stores the visibility data VD and the simulated image 10 or the dimension design value related thereto in association with each other (FIG. 6: step S55).

Next, when there is a further change in the dimension design value (parameter) (FIG. 6: Step S56: YES), the process returns to Step S52 to generate a new simulated image 10.
Here, the case where the parameter is further changed includes various cases. As an example, in addition to the case where a plurality of dimension design values have been input in advance in step S51, a user who has visually input the visibility data VD by viewing the simulated image 10 and inputs the answer (FIG. 6: step S55) This may be the case when further changes in design values or other dimensional design values are entered.

  When the parameter change is completed (FIG. 6: step S56: NO), the determination unit 70 performs the determination process for the visibility of the simulated image 10 based on the visibility data VD stored in the answer storage unit 60 (FIG. 6). 6: Step S57). Such a determination indicates a result of parameter study in the light emitting device 200.

  Prior to the determination by the determination unit 70, it is preferable that the visual determination and answer input (FIG. 6: step S55) of the simulated image 10 be performed for a large number of users. Thereby, objective evaluation regarding the visibility of the simulation image 10 can be obtained.

  There are various methods of determination processing by the determination unit 70. As an example, a method of averaging the visibility data VD for each dimension design value and determining the size as a predetermined reference value is given. As a more specific example, when the average score (maximum 1, minimum 0) of the visibility data VD answered by a plurality of users is 0.8 or more, that is, the brightness unevenness is 4 or more of 5 people. When it is answered that it cannot be visually checked, it is determined that the dimension design value is not visible. Then, when the average score of the visibility data VD is less than 0.8, that is, when it is answered that the luminance unevenness can be seen by exceeding 1 out of 5 people, the dimension design value is determined to be visible.

After making this determination by the number of dimension design values according to the parameter study, the result is output by the output unit 72 (FIG. 6: step S58).
The mode of output by the output unit 72 is not particularly limited. For example, the determination result (two steps or three steps or more) regarding the visibility of the luminance unevenness of the simulated image 10 and the dimension design value for the simulated image 10 are output together. Thereby, the user can know the dimension design value by which the brightness nonuniformity of the light-emitting device 200 is suppressed below predetermined. By adopting such a dimensional design value, the optical quality when the light emitting device 200 is produced can be realized as desired, and useful information is provided in processes such as design and quality control of the light emitting device 200. .

  In addition, the output unit 72 of the present embodiment outputs threshold information indicating the dimension design value for the simulated image 10 that is determined that the degree of unevenness visibility is greater than or equal to a predetermined value.

  Here, the threshold information refers to the case where the visibility of the periodic unevenness of the corresponding simulated image 10 is reversed to be visually recognizable or not visually recognizable in two consecutive dimensional design values whose numerical values are changed in a plurality of stages. It means one of the two dimension design values.

  When the output unit 72 outputs such threshold information, the user can know a critical dimension design value that just satisfies the requirement for visibility of luminance unevenness, and is useful information in designing the light emitting device 200. Can be obtained.

  It should be noted that various modifications are allowed for this embodiment.

For example, the manufacturing condition of the optical element 210 may be used as an input value related to the design dimension value.
That is, the condition storage unit 22 of this modification may store the manufacturing conditions of the optical element 210 and the dimension design values generated in the manufactured optical element 210 in association with each other.
Then, the condition acquisition unit 20 may receive an input related to the manufacturing condition, refer to the condition storage unit 22, and call the dimension design value corresponding to the received manufacturing condition to acquire the input value.

  Here, examples of the manufacturing conditions of the optical element 210 include material characteristics and molding conditions of the optical element 210. Various parameters relating to material characteristics such as the type, concentration or composition ratio of various materials for manufacturing the optical element 210, or molding conditions such as molding temperature and molding speed, and dimensional design values of the optical element 210 to be molded The correspondence relationship is acquired in advance and stored in the condition storage unit 22.

  In the condition acquisition step S51, parameters relating to the manufacturing conditions are input to the condition acquisition unit 20. The condition acquisition unit 20 refers to the condition storage unit 22, acquires a dimensional design value based on the received parameter, and transmits it to the model acquisition unit 30. The model acquisition unit 30 may perform the model acquisition step S52 according to the method described above.

  That is, the image display method of the present modified example stores a manufacturing condition of the optical element 210 and a dimension design value generated in the manufactured optical element 210 in association with each other, a step of receiving an input related to the manufacturing condition, Calling the dimension design value corresponding to the accepted manufacturing condition with reference to the condition storage unit 22 and acquiring the input value.

  As another modification, the visibility data VD may be data obtained by individually evaluating the luminance unevenness of the simulated image 10 from a plurality of viewpoints. For example, the user may individually determine the overall luminance unevenness and the local luminance unevenness of the light emitting device 200, and the determination result may be received by the answer input unit 50 as the visibility data VD. That is, as shown in FIG. 3, the simulated image 10 has a nonuniform region that exists locally at the periphery of the image, such as a dark color portion DK, and a nonuniformity that changes in overall shade at the center of the image, such as a bright color portion BR. May be included. In such a case, the visibility of the local unevenness and the visibility of the overall unevenness are individually received by the visibility data VD, and the light emitting state of the light emitting device 200 is evaluated in a multifaceted manner by the determination unit 70. It becomes possible.

  In this method, the model is obtained after the generation of the simulated image 10 by the model acquisition unit 30, the display of the simulated image 10 by the display unit 40, and the acquisition of the visibility data VD by the answer input unit 50 are sequentially performed. Although the case of regenerating has been described as an example, the present invention is not limited to this. After the simulated images 10 corresponding to a plurality of dimensional design values are created in advance, they may be individually displayed on the display unit 40 and the user's visual results may be received by the answer input unit 50.

<Example>
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to the examples.

Example 1
An example in which the backlight having the structure shown in FIG. 2A is set as the light emitting device 200 and the CCFL is set as the optical element 210 is shown below. In this type of light emitting device 200, it is known that uneven brightness occurs on the diffusion plate 220 in the direction in which the optical elements 210 (CCFL) are arranged (the horizontal direction in the figure). Therefore, an attempt was made to make the luminance of the diffusion plate 220 as uniform as possible by changing the center-to-center distance L1, the end portion distance L2, and the number N of the optical elements 210.

  Therefore, the simulation was performed by simulating the actual luminance distribution of the backlight with the left-right direction of FIG. Here, the calculation is made assuming that the light emitting area is 300 × 400 mm and the X direction is 300 mm, and the influence of the reflector 230 is ignored for simplicity.

FIG. 2B shows the result (calculation result 1) described in the first embodiment, where the number N = 8 (equal spacing), the end distance L2 = the center distance L1 / 2. is there.
From this result, it can be seen that the brightness unevenness slightly occurs in the central portion of the light emitting device 200 (backlight) at the interval (L1) of the optical element 210, and the brightness decreases at the end portion.

FIG. 7 is a graph showing a result (calculation result 2) when the number N = 8 (equal intervals) and the end distance L2 = 0.
From this result, it can be seen that the luminance unevenness of the period (L1) of the optical element 210 at the center is worse than that in FIG.

FIG. 8 is a graph showing the result (calculation result 3) when the number N = 9 (equal intervals) and the end distance L2 = 0.
From this result, it can be seen that the luminance unevenness of the period (L1) of the optical element 210 at the center is suppressed as compared with FIG.

FIG. 9 is a graph showing a result (calculation result 4) when the number N = 10 (equal intervals) and the end distance L2 = 0.
From this result, it can be seen that the luminance unevenness of the period (L1) of the optical element 210 at the center is almost eliminated.

Based on the calculation results of FIG. 2 (b) and FIGS. 7 to 9, a grayscale image is displayed on a high-precision display device (10-bit display) so as to have the same luminance fluctuation rate, and from a viewing distance of 1 m, Five subjects were visually inspected, and it was confirmed whether luminance unevenness was visible.
FIGS. 3 and 10 to 12 show model images (simulated images 10) with uneven brightness displayed on the display.

Here, it is generally known that the visibility sensitivity of the luminance unevenness of a person hardly changes when the average luminance of the image is 10 [cd / m ² ] to 1000 [cd / m ² ]. (See FIG. 13 and Non-Patent Document 1).

FIG. 13 is a graph of visibility sensitivity in which the vertical axis represents the contrast threshold value representing the visibility sensitivity, and the horizontal axis represents the average luminance of the image. As shown in the figure, when the average luminance is 10 [cd / m ² ] or less, the contrast threshold increases as the average luminance decreases and the visual sensitivity becomes worse. However, at higher luminance, the sensitivity changes. Almost not seen.

Therefore, in FIGS. 3 and 10 to 12, the luminance of the light emitting device 200 (backlight) is converted into average luminance = 100 [cd / m ² ], and images having the same luminance variation rate are displayed.

The visibility judgment results by five subjects were as follows.
(1) Display result of FIG. 3 (1-1) The luminance unevenness of the dark color part DK at the end part was visually recognized by all five people.
(1-2) About the luminance unevenness of the bright color portion BR at the center, four out of five people could visually recognize.
(2) Display result of FIG. 10 (2-1) The luminance unevenness of the dark color portion DK at the end portion could not be visually recognized by all five people.
(2-2) All five persons were able to visually recognize the luminance unevenness of the bright color part BR at the center.
(3) Display result of FIG. 11 (3-1) The luminance unevenness of the dark color portion DK at the end portion could not be visually recognized by all five people.
(3-2) Three out of five people could visually recognize the luminance unevenness of the bright color portion BR at the center.
(4) Display result of FIG. 12 (4-1) The luminance unevenness of the dark color portion DK at the end portion could not be visually recognized by all five people.
(4-2) All five persons could not visually recognize the luminance unevenness of the bright color portion BR at the center.

  From the display result and the visibility determination result of this embodiment, in the backlight having the same luminance distribution as the CCFL used in the current calculation, nine or more, preferably ten CCFLs are arranged from the viewpoint of luminance uniformity. It was suggested that there is a need. It was also found that dark color portions at both ends of the backlight can be eliminated by making the end portion distance L2 close to zero.

(Example 2)
An example in which a backlight for a liquid crystal television is set as the light emitting device 200 and a tandem light guide is set as the optical element 210 is shown below. A tandem type light guide is formed by stacking tile-shaped light guides bent in a key shape in a direction perpendicular to each other. Then, by arranging the light guide part or LED, which is the main cause of luminance unevenness, in the bent part and concealing it in the planar light emitting part of another adjacent light guide, only the planar light emitting part is planarized in a two-dimensional lattice shape. Can be arranged. However, this tandem type also has a big problem of unevenness of the light guide plate.
Hereinafter, a direction from the planar light emitting unit toward the light guide unit or the LED is defined as a Y direction, and an arrangement direction of the planar light emitting units is defined as an X direction.

  FIG. 14 is a graph showing the result of calculating the luminance variation in the X direction (calculation result 1) when the number of light guides is 1200 and the size of the light guide is 25 mm square. The decrease in luminance due to the seam was set to 25 mm pitch, and the luminance variation of the seam was set to 2%.

FIG. 15 is a graph showing the result of calculating the luminance variation in the X direction (calculation result 2) when the number of light guides is 2400 and the size of the light guide is 17.5 mm square. The brightness decrease due to the joint was 17.5 mm pitch, and the brightness variation of the joint was set to 2%.
When this result was compared with FIG. 14, the improvement of average luminance was seen by having increased the number of the light guides.

Based on the calculation results of FIGS. 14 and 15, a grayscale image was displayed on a high-precision display device (10-bit display) so as to have the same luminance difference. From a viewing distance of 1.5 m, 5 subjects were able to visually recognize this, and it was confirmed whether luminance unevenness could be visually recognized.
FIG. 16 and FIG. 17 show a model image (simulated image 10) with uneven brightness displayed on the display.

As described above, when the average luminance of the display image is 10 [cd / m ² ] to 1000 [cd / m ² ], the human visual sensitivity is substantially the same. For this reason, in this example, an image (simulated image 10) having an average luminance of 1/30 with respect to the luminance levels of FIGS.
Specifically, the average luminance in FIG. 16 is 70 [cd / m ² ], and the average luminance in FIG. 17 is 130 [cd / m ² ].

The visibility judgment results by five subjects were as follows.
(1) Display result of FIG. 16 The brightness unevenness of the seam was not visually recognized for all five people.
(2) Display result of FIG. 17 The brightness unevenness of the joint was visually recognized by all five people.

  From the display result and the visibility determination result of the present embodiment, in the case of the backlight having the luminance used in this calculation, the case where 1200 light guides having a size of 25 mm square are used and the size is 17.5 mm square. It was confirmed that the seam unevenness was less visible than when 2400 light guides were used.

(Example 3)
An example in which a liquid crystal display device is set as the light emitting device 200 and a film having a periodic structure is set as the optical element 210 will be described below. A prism film is given as an example of a film having a periodic structure.
Here, moire fringes may occur due to the interaction between the film having a periodic structure such as a prism film and the pixel structure of the LCD panel. In many cases, the structure of the element is too small to be seen with the naked eye, but the interference pattern between the elements can be easily seen as moire fringes. Moire fringes are generated in any film as long as it has a periodic structure, not limited to a prism film.

  In addition, when there are two prism films crossed in the display, two moire patterns orthogonal to each other may occur. The prism film having the RGB sub-pixel arrangement direction as a periodic direction generates gray stripes due to the interaction with the vertical pitch direction of the LCD panel. On the other hand, the prism film parallel to the vertical axis perpendicular thereto generates colored stripes due to the interaction with the horizontal pitch direction of the LCD panel.

Here, the moiré frequency F _m and the moiré period P _m due to the interaction between the prism films and the pixels stacked on each other can be expressed by the following equations. Here, P _p is the pixel pitch of the LCD panel, P _f is the pitch of the prism film, and m is a natural number.

_Fm = m / _Pp- 1 / _Pf Formula (2)
P _m = | 1 / F _m | Formula (3)

FIG. 18 shows the moire period when the pixel pitch P _p = 150 μm and the prism pitch P _f = 20 to 60 μm.

From equations (2) and (3), it can be seen that the moire cycle approaches infinity when P _p = m · P _f . That is, when the pixel pitch is close to a multiple of the prism pitch, the moire period becomes significantly large, and moire becomes conspicuous.

  In this embodiment, the moiré contrast is obtained in advance by measurement or calculation, and the simulated image 10 having the non-uniformity of the moiré period obtained by the expression (3) is generated in the contrast, and this is displayed on the high-precision display device (10-bit display). ). Thereby, the visibility of unevenness caused by moire can be determined without actually overlapping the patterns, so that the visibility of the assumed moire fringes can be confirmed.

In this embodiment, the pixel pitch P _p of the LCD panel is 150 μm, and the prism pitch P _f of the prism film is (a) 25.5 μm, (b) 26.5 μm, (c) 27.5 μm, (d) 28 0.5 μm and (e) 29.5 μm. The luminance difference caused by moire was set to ΔT = 5% based on the measured value.
In this case, the calculated value of the moire period _{P m,} respectively (a) 1.28mm, (b) 0.42mm, (c) 0.33mm, (d) 0.57mm, became (e) 1.77 mm .

  The unevenness corresponding to this was displayed on the high-precision display device (10-bit display) as the luminance unevenness of the sine waveform, and from the viewing distance of 0.5 m, it was confirmed whether or not the viewing was approved by five subjects.

The visibility judgment results by five subjects were as follows.
(A) All 5 people could see brightness unevenness (b) All 5 people could not see brightness unevenness (c) All 5 people could not see brightness unevenness (d) 2 out of 5 people could see brightness unevenness Visible (e) All 5 people saw uneven brightness

Therefore, in the case of this embodiment, the prism patterns of the prism film moire fringes can not be visually recognized, such as the value of the moiré period P _m is equal to or less than about 0.4 mm, prisms (b) or (c) it can be determined that it is preferable to the pitch P _f.

From the above embodiments, the usefulness and feasibility of the uneven visibility determination technique according to the present invention can be understood.
Hereinafter, examples of the reference form will be added.
1. An image display device for displaying an image showing a light emission state of a light emitting device including optical elements arranged periodically,
A condition acquisition unit that acquires a plurality of input values related to at least one of the dimension design values of the optical element;
A model acquisition unit that acquires an image showing a visual periodic variation related to a light emission state of the light emitting device when the dimension design value of the optical element is the input value;
A display unit for displaying the plurality of generated images;
An image display device.
2. An answer input unit that accepts input of visibility data representing visibility of the unevenness of the period of the displayed image;
An answer storage unit for storing the received visibility data;
A determination unit that refers to the answer storage unit and determines a degree of visibility of the unevenness; and
The image display apparatus according to 1, further comprising:
3. 3. The image display device according to 2, further comprising an output unit that outputs threshold information indicating the dimension design value related to the image for which the degree of visibility is determined to be greater than or less than a predetermined value.
4). The image display device according to any one of 1 to 3, wherein the model acquisition unit stores the dimension design value of the optical element and the luminance of the light emitting device in association with each other.
5). The image display device according to any one of 1 to 4, wherein the display unit alternately displays the plurality of images showing the unevenness of the cycle and a clear image without the unevenness of the cycle.
6). The optical element is any one of 1 to 5 which is a light source of the light emitting device, an optical film that diffuses or collects transmitted light that passes through the optical element, or a phase difference control member that imparts a phase difference to the transmitted light. The image display device described in 1.
7). A condition storage unit for storing the manufacturing condition of the optical element and the dimension design value generated in the manufactured optical element in association with each other;
The condition acquisition unit receives an input related to the manufacturing condition, refers to the condition storage unit, calls the dimension design value corresponding to the received manufacturing condition, and acquires the input value. The image display device described.
8). A computer program for an image display device for displaying an image showing a light emission state of a light emitting device including optical elements arranged periodically,
Condition acquisition processing for acquiring a plurality of input values related to at least one of the dimension design values of the optical element;
A model acquisition process for generating an image showing a visual periodic variation in the light emitting state of the light emitting device when the dimension design value of the optical element is the input value;
Display processing for displaying the plurality of generated images;
Is executed by the image display device.
9. An image display method for displaying an image showing a light emission state of a light emitting device including optical elements arranged periodically,
A condition acquisition step of acquiring a plurality of input values related to at least one of the dimension design values of the optical element;
A model acquisition step of generating an image showing a visual period variation related to a light emitting state of the light emitting device when the dimension design value of the optical element is the input value;
A display step for displaying the plurality of generated images;
An image display method including:

DESCRIPTION OF SYMBOLS 10 Simulated image 20 Condition acquisition part 22 Condition storage part 30 Model acquisition part 32 Calculation part 34 Storage part 40 Display part 42 Display control part 50 Answer input part 60 Answer storage part 70 Determination part 72 Output part 90 Bus 100 Image display apparatus 110 Image Display device 200 Light emitting device 210 Optical element 220 Diffuser plate 230 Reflector plate 240 Case

Claims (9)

An image display device that displays an image indicating a light emitting state of a light emitting device, including a plurality of optical elements arranged periodically, a housing containing the optical elements, and a diffusion plate facing the optical elements. And
The center-to-center distance between the adjacent optical elements, the distance from the center of the optical element at both ends to the housing, the distance between the optical element and the diffusion plate, the number of the optical elements, the width dimension of the housing, and A condition acquisition unit for acquiring an input value related to at least one dimension design value among the optical characteristic values of each of the plurality of optical elements ;
A model acquisition unit that acquires an image showing a visual periodic variation of the light emitting state of the light emitting device when designed according to the input value ;
A display unit for displaying the plurality of acquired images;
An image display device. An answer input unit that accepts input of visibility data representing visibility of the unevenness of the period of the displayed image;
An answer storage unit for storing the received visibility data;
A determination unit that refers to the answer storage unit and determines a degree of visibility of the unevenness of the period ;
The image display device according to claim 1, further comprising:   The image display apparatus according to claim 2, further comprising: an output unit that outputs threshold information indicating the dimension design value related to the image for which the degree of visibility is determined to be greater than or less than a predetermined value.   The image display device according to any one of claims 1 to 3, wherein the model acquisition unit stores the dimension design value of the optical element and the luminance of the light emitting device in association with each other. 5. The image display device according to claim 1, wherein the display unit alternately displays the plurality of images showing the non-uniformity of the cycle and a clear image without the non-uniformity of the cycle .   6. The optical element according to claim 1, wherein the optical element is a light source of the light emitting device, an optical film that diffuses or collects transmitted light that passes through the optical element, or a phase difference control member that imparts a phase difference to the transmitted light. The image display apparatus as described in any one. A condition storage unit for storing the manufacturing condition of the optical element and the dimension design value generated in the manufactured optical element in association with each other;
The said condition acquisition part receives the input regarding the said manufacturing conditions, refers to the said condition memory | storage part, calls the said dimension design value corresponding to the received said manufacturing conditions, and acquires the said input value. The image display device according to claim 1. An image display device that displays an image indicating a light emission state of a light emitting device, including a plurality of optical elements arranged periodically, a housing containing the optical elements, and a diffusion plate facing the optical elements Computer program,
The distance between the centers of the adjacent optical elements, the distance from the center of the optical element at both ends to the casing, the distance between the optical elements and the diffusion plate, the number of the optical elements, the width dimension of the casing, a plurality A condition acquisition process for acquiring an input value related to at least one of the optical characteristic values of each of the optical elements ;
A model acquisition process for acquiring an image showing a visual period variation related to a light emission state of the light emitting device when designed according to the input value ;
A display process for displaying the plurality of acquired images;
Is executed by the image display device. An image display method for displaying an image indicating a light emission state of a light emitting device, comprising: a plurality of optical elements arranged periodically; a housing containing the optical elements; and a diffusion plate facing the optical elements. And
The distance between the centers of the adjacent optical elements, the distance from the center of the optical element at both ends to the casing, the distance between the optical elements and the diffusion plate, the number of the optical elements, the width dimension of the casing, a plurality A condition acquisition step of acquiring an input value relating to at least one of the optical characteristic values of each of the optical elements ;
A model acquisition step of acquiring an image showing a visual period variation related to a light emission state of the light emitting device when designed according to the input value ;
A display step of displaying the plurality of acquired images;
An image display method including: